Vordermeier HM, Cockle PJ, Whelan AO, Rhodes S, Chambers MA, Clifford D, Huygen K, Tascon R, Lowrie D, Colston MJ, Hewinson RG (2000) Effective DNA vaccination of cattle with the mycobacterial antigens MPB83 and MPB70 does not compromise the specificity of the comparative intradermal tuberculin skin test., Vaccine 19 (9-10) pp. 1246-1255
The current tuberculin test and slaughter strategy for the control of bovine tuberculosis in cattle has failed to prevent a sharp rise in cases over recent years, especially in the south-west of England. A recent scientific review has concluded that the development of a cattle vaccine holds the best prospect for tuberculosis control in British herds. In order to continue with test and slaughter-based control strategies, the development of TB vaccines that do not compromise the specificity of the tuberculin skin test are required. This report describes results of cattle vaccination experiments with TB DNA vaccines expressing the mycobacterial antigens MPB70, MPB83, and Ag85A and constitutes the first published vaccination study with DNA vaccines undertaken in a target host species. All calves vaccinated with the MPB83 expressing plasmid demonstrated potent cellular immune responses, characterised by CD4(+) T cells producing interferon-gamma as well as humoral immunity characterised by IgG1 biased specific antibodies. Vaccination with MPB70 was less effective with immune responses only observed in half of the vaccinated animals, while vaccination with Ag85A did not result in vaccine-induced immune responses. Intramuscular vaccination was found to stimulate stronger cellular responses than intradermal immunisation. Significantly, the specificity of tuberculin skin testing was not compromised by DNA vaccination since none of the vaccinated calves showed positive skin test reactivity.
Knobloch H, Schroedl W, Turner C, Chambers M, Reinhold P (2010) Electronic nose responses and acute phase proteins correlate in blood using a bovine model of respiratory infection, SENSORS AND ACTUATORS B-CHEMICAL 144 (1) pp. 81-87 ELSEVIER SCIENCE SA
Lesellier S, Palmer S, Dalley DJ, Davé D, Johnson L, Hewinson RG, Chambers MA (2006) The safety and immunogenicity of Bacillus Calmette-Guérin (BCG) vaccine in European badgers (Meles meles)., Vet Immunol Immunopathol 112 (1-2) pp. 24-37
European badgers (Meles meles) are a wildlife reservoir for Mycobacterium bovis (M. bovis) in Great Britain (GB) and the Republic of Ireland and therefore constitute a potential source of infection for cattle. Reduction of badger densities in the Republic of Ireland has resulted in an associated reduction in the risk of a herd break-down with bovine tuberculosis and a study to determine whether this is also the case in GB has been running since 1997. If badgers are a significant source of M. bovis infection for cattle, vaccinating badgers with Bacillus Calmette-Guérin (BCG) might prove to be a long term, cost-effective strategy for controlling bovine tuberculosis whilst preserving badger populations. As a first step towards BCG vaccination of wild badgers, it was necessary to demonstrate safety of the vaccine in captive badgers. Therefore, captive badgers were vaccinated with a commercial source of BCG that is already licensed for administration to humans in GB-BCG Danish SSI. Using a protocol prescribed by the Veterinary Medicines Directorate (VMD) of GB, badgers were vaccinated with two consecutive doses of BCG via either the subcutaneous (s.c.) or intra-muscular (i.m.) routes. The first dose was high, ranging from 16 to 22 x 10(7) colony-forming units (CFU), and was followed 15 weeks later by a lower dose in the range of 4-7 x 10(5)CFU. Local reaction at the site of injection and general responses (body temperature, haematology and blood serum chemistry), behaviour and excretion of BCG were monitored for 28 weeks from the time of the first vaccination. The only side-effect observed was the occurrence of localised swelling at the site of BCG injection that disappeared 48 days after i.m. vaccination but persisted longer in the group vaccinated by the s.c. route. Immunological responses were measured at regular intervals. Strong cellular responses were observed 13 days after the first vaccination, which persisted for 76 days. The lower dose induced a weaker and shorter-lived response.
Lesellier S, Corner L, Costello E, Lyashchenko K, Greenwald R, Esfandiari J, Singh M, Hewinsone RG, Chambers M, Gormley E (2009) Immunological responses and protective immunity in BCG vaccinated badgers following endobronchial infection with Mycobacterium bovis, VACCINE 27 (3) pp. 402-409 ELSEVIER SCI LTD
Delahay RJ, Walker N, Smith GS, Wilkinson D, Clifton-Hadley RS, Cheeseman CL, Tomlinson AJ, Chambers MA (2013) Long-term temporal trends and estimated transmission rates for Mycobacterium bovis infection in an undisturbed high-density badger (Meles meles) population, EPIDEMIOLOGY AND INFECTION 141 (7) pp. 1445-1456 CAMBRIDGE UNIV PRESS
Tomlinson AJ, Chambers MA, Carter SP, Wilson GJ, Smith GC, McDonald RA, Delahay RJ (2013) Heterogeneity in the risk of Mycobacterium bovis infection in European badger (Meles meles) cubs, EPIDEMIOLOGY AND INFECTION 141 (7) pp. 1458-1466 CAMBRIDGE UNIV PRESS
Buddle BM, Skinner MA, Chambers MA (2000) Immunological approaches to the control of tuberculosis in wildlife reservoirs, VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 74 (1-2) pp. 1-16 ELSEVIER SCIENCE BV
Haile M, Hamasur B, Jaxmar T, Gavier-Widen D, Chambers MA, Sanchez B, Schroder U, Kallenius G, Svenson SB, Pawlowski A (2005) Nasal boost with adjuvanted heat-killed BCG or arabinomannan-protein conjugate improves primary BCG-induced protection in C57BL/6 mice, TUBERCULOSIS 85 (1-2) pp. 107-114 CHURCHILL LIVINGSTONE
Wooff E, Michell SL, Gordon SV, Chambers MA, Bardarov S, Jacobs WR, Hewinson RG, Wheeler PR (2002) Functional genomics reveals the sole sulphate transporter of the Mycobacterium tuberculosis complex and its relevance to the acquisition of sulphur in vivo., Mol Microbiol 43 (3) pp. 653-663
Sulphur is essential for some of the most vital biological activities such as translation initiation and redox maintenance, and genes involved in sulphur metabolism have been implicated in virulence. Mycobacterium tuberculosis has three predicted genes for the prototrophic acquisition of sulphur as sulphate: cysA, part of an ABC transporter, and cysA2 and A3, SseC sulphotransferases. Screening for amino acid auxotrophs of Mycobacterium bovis BCG, obtained by transposon mutagenesis, was used to select methionine auxotrophs requiring a sulphur-containing amino acid for growth. We have characterized one of these auxotrophs as being disrupted in cysA. Both the cysA mutant and a previously identified mutant in an upstream gene, subI, were functionally characterized as being completely unable to take up sulphate. Complementation of the cysA mutant with the wild-type gene from M. tuberculosis restored prototrophy and the ability to take up sulphate with the functional characteristics of an ABC transporter. Hence, it appears that this is the sole locus encoding inorganic sulphur transport in the M. tuberculosis complex.
Kampfer S, Dalley D, Hewinson RG, Chambers MA, Singh M (2003) Multi-antigen ELISA for enhanced diagnosis of tuberculosis in badgers, VETERINARY RECORD 153 (13) pp. 403-404 BRITISH VETERINARY ASSOC
Chambers MA (2013) Review of the Diagnosis of Tuberculosis in Non-Bovid Wildlife Species Using Immunological Methods - An Update of Published Work Since 2009, TRANSBOUNDARY AND EMERGING DISEASES 60 pp. 14-27 WILEY-BLACKWELL
Knobloch H, Koehler H, Commander N, Reinhold P, Turner C, Chambers M (2009) Volatile Organic Compound (VOC) Analysis For Disease Detection: Proof Of Principle For Field Studies Detecting Paratuberculosis And Brucellosis, OLFACTION AND ELECTRONIC NOSE, PROCEEDINGS 1137 pp. 195-197 AMER INST PHYSICS
Lesellier S, Dalley D, Dave D, Palmer S, Hewinson G, Chambers M (2005) Evaluation of BCG vaccine safety and immunogenicity in badgers, IMMUNOLOGY 116 pp. 109-109 BLACKWELL PUBLISHING
Spooner AD, Bessant C, Turner C, Knobloch H, Chambers M (2009) Evaluation of a combination of SIFT-MS and multivariate data analysis for the diagnosis of Mycobacterium bovis in wild badgers, ANALYST 134 (9) pp. 1922-1927 ROYAL SOC CHEMISTRY
Jones RM, Ashford R, Cork J, Palmer S, Wood E, Spyvee P, Parks S, Bennett A, Brewer J, Delahay R, Chambers M, Sawyer J (2013) Evaluation of a method to detect Mycobacterium bovis in air samples from infected Eurasian badgers (Meles meles) and their setts, LETTERS IN APPLIED MICROBIOLOGY 56 (5) pp. 361-365 WILEY-BLACKWELL
Lyashchenko KP, Greenwald R, Esfandiari J, Chambers MA, Vicente J, Gortazar C, Santos N, Correia-Neves M, Buddle BM, Jackson R, O'Brien DJ, Schmitt S, Palmer MV, Delahay RJ, Waters WR (2008) Animal-side serologic assay for rapid detection of Mycobacterium bovis infection in multiple species of free-ranging wildlife, VETERINARY MICROBIOLOGY 132 (3-4) pp. 283-292 ELSEVIER SCIENCE BV
Marshall BG, Chambers MA (1998) Central nervous system tuberculosis - The paradox of the host immune response, JOURNAL OF INFECTION 36 (1) pp. 3-4 W B SAUNDERS CO LTD
Chambers MA, Gavier-Widén D, Hewinson RG (2004) Antibody bound to the surface antigen MPB83 of Mycobacterium bovis enhances survival against high dose and low dose challenge., FEMS Immunol Med Microbiol 41 (2) pp. 93-100
Tuberculosis caused by infection with Mycobacterium tuberculosis or Mycobacterium bovis is a significant disease of man and animals. Whilst cellular immunity is the major immunological component required for protection against these organisms, recent reports have suggested that monoclonal antibodies can modify infection with M. tuberculosis. To test whether the same was true for M. bovis infection, we determined the effect of preincubation of M. bovis with a monoclonal antibody on subsequent intravenous infection of mice. Antibodies bound to the surface of M. bovis increased the survival time of mice infected with M. bovis and changed the morphology of granulomas and the distribution of acid-fast bacilli in the lung. These studies suggest that antibodies directed to the surface of virulent mycobacteria can modulate their virulence in vivo.
Dalley D, Chambers MA, Cockle P, Pressling W, Gavier-Widén D, Hewinson RG (1999) A lymphocyte transformation assay for the detection of Mycobacterium bovis infection in the Eurasian badger (Meles meles)., Vet Immunol Immunopathol 70 (1-2) pp. 85-94
The Eurasian badger (Meles meles) is a significant wildlife reservoir of Mycobacterium bovis in Great Britain. Improved control strategies against the disease in badgers require the development of diagnostic tests and vaccines. Here, we report the development of a comparative lymphocyte transformation assay (LTA) using bovine and avian tuberculin as antigen to detect cell-mediated responses in M. bovis-infected badgers. In a pilot study, the performance of this assay was compared with the existing indirect ELISA assay for the detection of tuberculous badgers. The sensitivity of the Comparative LTA was 87.5% compared with 62.5% for the indirect ELISA whereas the ELISA test gave a greater specificity (100% compared with 84.6% for the comparative LTA). Preliminary evidence suggests that for the comparative LTA, the blood may be stored overnight prior to testing and that this procedure might improve the specificity of the assay without compromising the sensitivity.
Chambers MA, Lyashchenko KP, Greenwald R, Esfandiari J, James E, Barker L, Jones J, Watkins G, Rolfe S (2010) Evaluation of a Rapid Serological Test for the Determination of Mycobacterium bovis Infection in Badgers (Meles meles) Found Dead, CLINICAL AND VACCINE IMMUNOLOGY 17 (3) pp. 408-411 AMER SOC MICROBIOLOGY
Lesellier S, Corner L, Costello E, Sleeman P, Lyashchenko K, Greenwald R, Esfandiari J, Singh M, Hewinson RG, Chambers M, Gormley E (2008) Antigen specific immunological responses of badgers (Meles meles) experimentally infected with Mycobacterium bovis, VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 122 (1-2) pp. 35-45 ELSEVIER SCIENCE BV
Marshall BG, Chambers MA, Wangoo A, Cook HT, Young DB, Shaw RJ (1996) Understanding the different inflammatory responses to live and dead BCG: A prerequisite for improved vaccine design, Thorax 51 (SUPPL. 3)
Specific antituberculous resistance appears to be induced following inoculation of live but not dead BCG. This dependence on BCG viability may explain the diverse responses in terms of protective immunity in clinical trials of BCG conducted worldwide over the last thirty years. In order to dissect out simple parameters which may differentiate a protective from a non-protective response, we have developed a murine in vivo model of experimental BCG infection to study the immune response in draining lymph nodes following footpad inoculation with either live or killed BCG preparations. In this model, live but not heat-killed BCG efficiently migrate to the draining lymph nodes and stimulate the early accumulation of mononuclear cells. In addition, live and heat-killed BCG stimulate different responses in terms of the level of expression of interferon-gamma, inducible nitric oxide (iNOS), as well as macrophage and dendritic cell markers in the draining lymph nodes. This divergent in vivo response was reproduced in vitro when pure macrophage cultures were infected with BCG and responded differently to live and dead preparations, producing significant levels of TNF and reactive nitrogen intermediates only when infected with live BCG. Taken together, these observations suggest that the differences encountered in vivo may be related to the ability of live BCG to migrate to local lymph node, where they cause the accumulation of cells expressing protective cytokines and therefore inducing an efficient immune response. These findings may have important implications for the design of new anti-tuberculosis vaccines.
Chambers MA, Gavier-Widén D, Stanley PA, Hewinson RG (2000) Biochemical and haematological parameters associated with tuberculosis in European badgers., Vet Rec 146 (25) pp. 734-735
Hogarth PJ, Logan KE, Ferraz JC, Hewinson RG, Chambers MA (2006) Protective efficacy induced by Mycobacterium bovis bacille Calmette-Guerin can be augmented in an antigen independent manner by use of non-coding plasmid DNA, VACCINE 24 (1) pp. 95-101 ELSEVIER SCI LTD
Williams A, Davies A, Marsh PD, Chambers MA, Hewinson RG (2000) Comparison of the protective efficacy of bacille Calmette-Guerin vaccination against aerosol challenge with Mycobacterium tuberculosis and Mycobacterium bovis, CLINICAL INFECTIOUS DISEASES 30 pp. S299-S301 OXFORD UNIV PRESS INC
CHAMBERS M, WEI Z, COLEMAN N, NASH A, STANLEY M (1994) NATURAL PRESENTATION OF HUMAN PAPILLOMAVIRUS TYPE-16 E7 PROTEIN TO IMMUNOCOMPETENT MICE RESULTS IN ANTIGEN-SPECIFIC SENSITIZATION OR SUSTAINED UNRESPONSIVENESS, EUROPEAN JOURNAL OF IMMUNOLOGY 24 pp. 738-745
CHAMBERS M, MARSHALL B, BUNE A, LADVA S, COOK T, SHAW R, YOUNG D (1996) Different primary immune responses to BCG in a mouse model: Does the macrophage distinguish between viable and killed BCG?, JOURNAL OF PATHOLOGY 179 pp. A38-A38
Chambers MA, Carter SP, Wilson GJ, Jones G, Brown E, Hewinson RG, Vordermeier M (2014) Vaccination against tuberculosis in badgers and cattle: an overview of the challenges, developments and current research priorities in Great Britain., Vet Rec 175 (4) pp. 90-96
Bovine tuberculosis (TB) is a significant threat to the cattle industry in England and Wales. It is widely acknowledged that a combination of measures targeting both cattle and wildlife will be required to eradicate bovine TB or reduce its prevalence until European official freedom status is achieved. Vaccination of cattle and/or badgers could contribute to bovine TB control in Great Britain, although there are significant gaps in our knowledge regarding the impact that vaccination would actually have on bovine TB incidence. Laboratory studies have demonstrated that vaccination with BCG can reduce the progression and severity of TB in both badgers and cattle. This is encouraging in terms of the prospect of a sustained vaccination programme achieving reductions in disease prevalence; however, developing vaccines for tackling the problem of bovine TB is challenging, time-consuming and resource-intensive, as this review article sets out to explain.
Chambers MA, Stagg D, Gavier-Widén D, Lowrie D, Newell D, Hewinson RG (2001) A DNA vaccine encoding MPB83 from Mycobacterium bovis reduces M. bovis dissemination to the kidneys of mice and is expressed in primary cell cultures of the European badger (Meles meles)., Res Vet Sci 71 (2) pp. 119-126
Nucleic acid (DNA) vaccination against tuberculosis in the European badger (Meles meles) is one approach to addressing the escalating problem of bovine tuberculosis in Great Britain. The aim of vaccination is to reduce the burden of tuberculosis within the badger population and the shedding of Mycobacterium bovis to levels that would break the transmission of infection to cattle. To this end, the vaccine would be required to limit the amount of disseminated tuberculosis in the badger, especially dissemination to the kidney from where M. bovis can be shed in the urine. A promising candidate DNA vaccine encoding a 26 kDa major antigen (MPB83) of M. bovis was evaluated in a mouse model of disseminated M. bovis infection. Using the DNA vaccine, protection against infection of the kidney was found to be greater than that achieved with the current live vaccine, Bacille Calmette-Guerin (BCG). Kidney tissue and skeletal muscle from the badger was used to derive primary cell cultures in which to examine the expression of MPB83 following transfection with the DNA vaccine. Kidney cortex gave rise to a monotypic culture of epithelial cells whilst the muscle gave rise to a mixed culture of fibroblasts and myoblasts. During culture the myoblasts differentiated into multinucleated myotubes, verified by immunofluorescent detection of mammalian desmin. Successful expression of MPB83 by transfected epithelial and myotube cells was confirmed by immunofluorescence using a monoclonal antibody specific to the protein. These observations fulfil the early requirements for the development of a DNA vaccine for badger tuberculosis.
Dalley DJ, Hogarth PJ, Hughes S, Hewinson RG, Chambers MA (2004) Cloning and sequencing of badger (Meles meles) interferon gamma and its detection in badger lymphocytes., Vet Immunol Immunopathol 101 (1-2) pp. 19-30
The European badger (Meles meles) has been identified as a reservoir for Mycobacterium bovis and is implicated in the maintenance and transmission of tuberculosis in cattle. There is a need for a sensitive test of M. bovis infection in badgers and the current serodiagnostic test used for this purpose has low sensitivity. As observed for other species, assay of interferon-gamma (IFNgamma) produced in response to M. bovis antigens is a more sensitive test of tuberculosis. With this objective in sight, we report the first step in the development of an ELISA for badger IFNgamma. The badger IFNgamma gene was cloned and sequenced and used to generate a specific polyclonal antibody to the cytokine. The gene sequence demonstrated regions that were conserved within the IFNgamma genes of other mammals. The badger sequence was most similar to the canine, showing similar structural organisation of the gene and 88% amino acid identity. Rabbits were immunised with DNA encoding badger IFNgamma and the resulting polyclonal antiserum demonstrated specificity for canine IFNgamma by immunoblot of a commercial recombinant canine IFNgamma. The antiserum was used to detect intracellular badger IFNgamma by flow cytometry analysis of badger lymphocytes stimulated with mitogen.
Tree JA, Smith S, Baker N, Clark S, Aldwell FE, Chambers M, Williams A, Marsh PD (2012) Method for assessing IFN-gamma responses in guinea pigs during TB vaccine trials, LETTERS IN APPLIED MICROBIOLOGY 55 (4) pp. 295-300 WILEY-BLACKWELL
Carter SP, Chambers MA, Rushton SP, Shirley MDF, Schuchert P, Pietravalle S, Murray A, Rogers F, Gettinby G, Smith GC, Delahay RJ, Hewinson RG, McDonald RA (2012) BCG Vaccination Reduces Risk of Tuberculosis Infection in Vaccinated Badgers and Unvaccinated Badger Cubs, PLOS ONE 7 (12) ARTN e49833 PUBLIC LIBRARY SCIENCE
Chambers M, Dougan G, Newman J, Brown F, Crowther J, Mould AP, Humphries MJ, Francis MJ, Clarke B, Brown AL, Rowlands D (1996) Chimeric hepatitis B virus core particles as probes for studying peptide-integrin interactions, JOURNAL OF VIROLOGY 70 (6) pp. 4045-4052 AMER SOC MICROBIOLOGY
Kiran D, Podell BK, Chambers M, Basaraba RJ (2016) Host-directed therapy targeting the Mycobacterium tuberculosis granuloma: a review, Seminars in Immunopathology 38 (2) pp. 167-183
© 2015, The Author(s).Infection by the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb) is a major cause of morbidity and mortality worldwide. Slow progress has been made in lessening the impact of tuberculosis (TB) on human health, especially in parts of the world where Mtb is endemic. Due to the complexity of TB disease, there is still an urgent need to improve diagnosis, prevention, and treatment strategies to control global spread of disease. Active research targeting avenues to prevent infection or transmission through vaccination, to diagnose asymptomatic carriers of Mtb, and to improve antimicrobial drug treatment responses is ongoing. However, this research is hampered by a relatively poor understanding of the pathogenesis of early infection and the factors that contribute to host susceptibility, protection, and the development of active disease. There is increasing interest in the development of adjunctive therapy that will aid the host in responding to Mtb infection appropriately thereby improving the effectiveness of current and future drug treatments. In this review, we summarize what is known about the host response to Mtb infection in humans and animal models and highlight potential therapeutic targets involved in TB granuloma formation and resolution. Strategies designed to shift the balance of TB granuloma formation toward protective rather than destructive processes are discussed based on our current knowledge. These therapeutic strategies are based on the assumption that granuloma formation, although thought to prevent the spread of the tubercle bacillus within and between individuals contributes to manifestations of active TB disease in human patients when left unchecked. This effect of granuloma formation favors the spread of infection and impairs antimicrobial drug treatment. By gaining a better understanding of the mechanisms by which Mtb infection contributes to irreversible tissue damage, down regulates protective immune responses, and delays tissue healing, new treatment strategies can be rationally designed. Granuloma-targeted therapy is advantageous because it allows for the repurpose of existing drugs used to treat other communicable and non-communicable diseases as adjunctive therapies combined with existing and future anti-TB drugs. Thus, the development of adjunctive, granuloma-targeted therapy, like other host-directed therapies, may benefit from the availability of approved drugs to aid in treatment and pre
Chambers MA, Graham SP, La Ragione RM (2016) Challenges in veterinary vaccine development and immunization, In: Methods in Molecular Biology 1404 pp. 3-35
In the UK there has been a sharp rise in the incidence of bovine tuberculosis since the early 1990s and the badger has been identified as an important wildlife reservoir for this infection. Infected badgers can excrete Mycobacterium bovis, putting other badgers and cattle at risk of becoming infected. Vaccination has been proposed as an approach to reducing the excretion of M. bovis by tuberculous badgers. In order to evaluate the efficacy of a badger vaccine it will be necessary to accurately determine the number of badgers excreting M. bovis without removing them for post-mortem evaluation. The existing live tests for tuberculosis in the badger (culture, indirect ELISA, Western blot) have not been assessed for their ability to detect badgers excreting M. bovis. Over the past 18 years, badgers from 31 social groups have been trapped and sampled in a study area of the Cotswold escarpment. We have examined the serological responses of 128 badgers trapped between 1985 and 1998 from social groups where M. bovis infection was endemic. These responses were compared with culture from faeces, urine, tracheal aspirates and bite wound swabs taken from these animals while alive. ELISA was found to be more sensitive than Western blot in detecting badgers excreting M. bovis. The majority of culture-positive badgers excreted M. bovis intermittently over the period of study. As a result, there was only a 27.5% chance of sampling a badger for culture when it was excreting M. bovis. In contrast, a positive ELISA result correctly predicted 68.2% of badgers with a history of excreting M. bovis. In the absence of alternative live tests for the badger, the Brock Test indirect ELISA appears to be more valuable than culture for measuring the effect of vaccination on reducing the number of badgers at risk of transmitting tuberculosis.
Vordermeier HM, Chambers MA, Buddle BM, Pollock JM, Hewinson RG (2006) Progress in the development of vaccines and diagnostic reagents to control tuberculosis in cattle., Vet J 171 (2) pp. 229-244
The sharp rise of bovine tuberculosis (TB) in Great Britain and the continuing problem of wild life reservoirs in countries such as New Zealand and Great Britain have resulted in increased research efforts into the disease. Two of the goals of this research are to develop (1) cattle vaccines against TB and (2) associated diagnostic reagents that can differentiate between vaccinated and infected animals (differential diagnosis). This review summarises recent progress and describes efforts to increase the protective efficacy of the only potential TB vaccine currently available, Mycobacterium bovis BCG, and to develop specific reagents for differential diagnosis. Vaccination strategies based on DNA or protein subunit vaccination, vaccination with live viral vectors as well as heterologous prime-boost scenarios are discussed. In addition, we outline results from studies aimed at developing diagnostic reagents to allow the distinction of vaccinated from infected animals, for example antigens that are not expressed by vaccines like Mycobacterium bovis Bacille-Calmette-Guérin, but recognised strongly in Mycobacterium bovis infected cattle.
MARSHALL B, CHAMBERS M, WANGOO A, SHAW R, YOUNG D (1997) Production of tumor necrosis factor and nitric oxide by macrophages infected with live and dead mycobacteria and their suppression by an interleukin-10-secreting recombinant, INFECTION AND IMMUNITY 65 pp. 1931-1935
CHAMBERS M, STACEY S, ARRAND J, STANLEY M (1994) DELAYED-TYPE HYPERSENSITIVITY RESPONSE TO HUMAN PAPILLOMAVIRUS TYPE-16 E6 PROTEIN IN A MOUSE MODEL, JOURNAL OF GENERAL VIROLOGY 75 pp. 165-169
CHAMBERS M, MARSHALL B, WANGOO A, BUNE A, COOK H, SHAW R, YOUNG D (1997) Differential responses to challenge with live and dead Mycobacterium bovis Bacillus Calmette-Guerin, JOURNAL OF IMMUNOLOGY 158 pp. 1742-1748
© 2014 John Wiley & Sons Ltd.Bovine tuberculosis is one of the biggest challenges facing cattle farming in Great Britain. European badgers (Meles meles) are a reservoir host for the causal agent, Mycobacterium bovis. There have been significant recent advances in diagnostic testing for tuberculosis in humans, cattle and badgers, with the development of species-specific assays for interferon-³ (IFN-³), an important cytokine in tuberculous infections. Using data collected from longitudinal studies of naturally infected wild badgers, we report that the magnitude of the IFN-³ response to M. bovis antigens at the disclosing test event was positively correlated with subsequent progression of disease to a seropositive or excreting state. In addition, we show that the magnitude of the IFN-³ response, despite fluctuation, declined with time after the disclosing event for all badgers, but remained significantly higher in those animals with evidence of disease progression. We discuss how our findings may be related to the immunopathogenesis of natural M. bovis infection in badgers.
Gavier-Widen D, Chambers MA, Palmer N, Newell DG, Hewinson RG (2001) Pathology of natural Mycobacterium bovis infection in European badgers (Meles meles) and its relationship with bacterial excretion., Vet Rec 148 (10) pp. 299-304
Sixteen European badgers (Meles meles) from three statutory removal operations were studied. Samples of tracheal aspirate, pooled lymph nodes and urine were cultured for mycobacteria. Seven of the badgers were infected with Mycobacterium bovis and had tuberculous pulmonary lesions which varied in severity from extensive granulomatous consolidation to microgranulomas which were not detectable grossly. Tuberculous lesions were also observed in the upper respiratory airways, intestines, kidneys, spleen, liver, thymus, pleura and lymph nodes. One badger had tuberculous bite wounds. The histopathological characteristics of the tuberculous reactions and the associated tissue damage in various organs, together with the gross pathology, indicate that both mildly and severely infected badgers have the potential to excrete M. bovis by several routes.
Balseiro A, Rodríguez O, González-Quirós P, Merediz I, Sevilla IA, Davé D, Dalley DJ, Lesellier S, Chambers MA, Bezos J, Muñoz M, Delahay RJ, Gortázar C, Prieto JM (2011) Infection of Eurasian badgers (Meles meles) with Mycobacterium bovis and Mycobacterium avium complex in Spain, Vet J 190 pp. e21-e25
The prevalence, distribution and pathology related to infection with Mycobacterium bovis and other mycobacteria were determined in trapped (n=36) and road-killed (n=121) badgers in Spain from 2006 to 2010. The prevalence of M. bovis based on bacteriological culture from road-killed badgers was 8/121 (6.6%) and from trapped badgers was 0/36 (0%). Tuberculosis/M. bovis infection was evident in 15/121 (12.4%) road-killed badgers when bacteriology and histopathology were combined. Mycobacterium avium complex was isolated by culture from the tracheal aspirate of 1/36 (2.8%) trapped badgers and from tissue pools from 8/121 (6.6%) road-killed badgers.
Salguero FJ, Lesellier S, Nunez A, Corner L, Crawshaw T, Chambers M (2010) INTRAMUSCULAR BCG VACCINATION REDUCES SIGNIFICANTLY THE PATHOLOGY INDUCED BY MYCOBACTERIUM BOVIS IN BADGERS (MELES MELES), JOURNAL OF COMPARATIVE PATHOLOGY 143 (4) pp. 347-347 ELSEVIER SCI LTD
Vordermeier HM, Chambers MA, Cockle PJ, Whelan AO, Simmons J, Hewinson RG (2002) Correlation of ESAT-6-specific gamma interferon production with pathology in cattle following Mycobacterium bovis BCG vaccination against experimental bovine tuberculosis., Infect Immun 70 (6) pp. 3026-3032
Vaccine development and the understanding of the pathology of bovine tuberculosis in cattle would be greatly facilitated by the definition of immunological correlates of protection and/or pathology. To address these questions, cattle were vaccinated with Mycobacterium bovis bacillus Calmette-Guérin (BCG) and were then challenged with virulent M. bovis. Applying a semiquantitative pathology-scoring system, we were able to demonstrate that BCG vaccination imparted significant protection by reducing the disease severity on average by 75%. Analysis of cellular immune responses following M. bovis challenge demonstrated that proliferative T-cell and gamma interferon (IFN-gamma) responses towards the M. bovis-specific antigen ESAT-6, whose gene is absent from BCG, were generally low in vaccinated animals but were high in all nonvaccinated calves. Importantly, the amount of ESAT-6-specific IFN-gamma measured by enzyme-linked immunosorbent assay after M. bovis challenge, but not the frequency of responding cells, correlated positively with the degree of pathology found 18 weeks after infection. Diagnostic reagents based on antigens not present in BCG, like ESAT-6 and CFP-10, were still able to distinguish BCG-vaccinated, diseased animals from BCG-vaccinated animals without signs of disease. In summary, our results suggest that the determination of ESAT-6-specific IFN-gamma, while not a direct correlate of protection, constitutes nevertheless a useful prognostic immunological marker predicting both vaccine efficacy and disease severity.
Chambers MA, Gavier-Widen D, Hewinson RG (2006) Histopathogenesis of experimental Mycobacterium bovis infection in mice., Res Vet Sci 80 (1) pp. 62-70
In-bred strains of mice are commonly used to model pathogenic infections due to their cost and utility. In order to understand better the nature of experimental tuberculosis in mice, we infected BALB/c mice with a virulent field isolate of Mycobacterium bovis. Mice were sacrificed at intervals in order to visualise the pathological lesions in major internal organs. Pathological lesions in tissues increased in number and severity over time and replicated many of the salient features observed in badgers and cattle infected with M. bovis. These similarities are discussed. Examination of pathological lesions at terminal stages of infection enabled us to suggest the lethal effects of M. bovis mediated through the host response. We conclude that the mouse is a relevant surrogate species in which to study the virulence of M. bovis, as well as the influence of vaccination on its pathogenicity.
Chambers MA (2009) Review of the Diagnosis and Study of Tuberculosis in Non-Bovine Wildlife Species Using Immunological Methods, TRANSBOUNDARY AND EMERGING DISEASES 56 (6-7) pp. 215-227 WILEY-BLACKWELL PUBLISHING, INC
Hogarth PJ, Logan KE, Vordermeier HM, Singh M, Hewinson RG, Chambers MA (2005) Protective immunity against Mycobacterium bovis induced by vaccination with Rv3109c--a member of the esat-6 gene family., Vaccine 23 (20) pp. 2557-2564
In a number of clinical studies the current TB vaccine, Mycobacterium bovis bacille Calmette-Guerin (BCG), has provided little or no protection against pulmonary tuberculosis in cattle and man. A new generation of vaccines is therefore required to replace or supplement BCG. Safety concerns surrounding a number of strategies make protein subunits an attractive approach. Moreover, novel prime-boost strategies based on primary immunisations with BCG are not only showing promise but also present a clear strategy for testing new TB vaccines in clinical studies. We report the evaluation of six protein vaccine candidates for their ability to induce protective immunity in a murine virulent M. bovis challenge model. One protein (Rv3019c) induced reproducibly significant protection in the spleen and lungs approaching that induced by BCG. Detailed analysis of antigen-specific T cell responses revealed that despite robust responses in the spleen and lungs of vaccinated mice, there was no correlation between these responses and the protective efficacy of the vaccine. Significantly, Rv3019c also stimulated IFN-gamma responses in PBMC from BCG vaccinated cattle, indicating its potential for use in a heterologous prime-boost strategy in conjunction with BCG in the target species.
Fend R, Geddes R, Lesellier S, Vordermeier HM, Corner LAL, Gormley E, Costello E, Hewinson RG, Marlin DJ, Woodman AC, Chambers MA (2005) Use of an electronic nose to diagnose Mycobacterium bovis infection in badgers and cattle, JOURNAL OF CLINICAL MICROBIOLOGY 43 (4) pp. 1745-1751 AMER SOC MICROBIOLOGY
Logan KE, Chambers MA, Hewinson RG, Hogarth PJ (2005) Frequency of IFN-gamma producing cells correlates with adjuvant enhancement of bacille Calmette-Guèrin induced protection against Mycobacterium bovis., Vaccine 23 (48-49) pp. 5526-5532
Tuberculosis caused by infection with Mycobacterium tuberculosis or Mycobacterium bovis remains one of the most important infectious diseases of man and animals. The current vaccine M. bovis Calmette-Guérin (BCG) demonstrates variable efficacy and so a more robust strategy to either replace, or more likely supplement it, is required. Prime-boost strategies where immunity induced by BCG is boosted by a second heterologous vaccine represent a promising avenue of research. We have evaluated the ability of a protein subunit vaccine using the antigen Rv3019c to either prime or boost immunity induced by BCG in a murine M. bovis challenge model. Despite the induction of anamnestic T cell responses, we report that antigen-independent immune stimulation with adjuvant in conjunction with BCG could enhance the level of protection induced by BCG alone. Importantly this improved protection correlated with pre-infection frequencies of ex vivo IFN-gamma producing cells in the spleen, providing a possible surrogate correlate of protection for future vaccination studies.
Chambers M, Graham SP, La Ragione RM (2016) Challenges in Veterinary Vaccine Development and Immunization, In: Thomas S (eds.), Vaccine Design 2 Vaccines for Veterinary Diseases 1 pp. 3-35 Springer
Gavier-Widén D, Chambers M, Gortázar C, Delahay R, Cromie R, Lindén A (2012) Mycobacteria Infections, In: Infectious Diseases of Wild Mammals and Birds in Europe pp. 265-292
Stanley M, Coleman N, Chambers M (1994) The host response to lesions induced by human papillomavirus., Ciba Foundation symposium 187 pp. 21-32
Human papillomaviruses (HPVs) are strictly intraepithelial pathogens: in the natural productive infection they induce benign epithelial proliferations of mucocutaneous surfaces, some of which may progress to malignancy. Benign HPV-induced lesions are chronic persistent growths; high levels of viral antigen are expressed in the apparent absence of a host immune response suggesting that these viruses have evolved efficient mechanisms of immune evasion. Cell-mediated responses are central in the pathogenesis of HPV and regression of both cutaneous and genital warts histologically resembles a delayed-type hypersensitivity response (DTH). The antigen(s) in the wart against which this response is initiated are not known but in an experimental murine model DTH responses to the E6 and E7 proteins of HPV-16 can be elicited when viral antigen is presented via the epithelial route. Priming with low levels of viral antigen in this model induces non-responsiveness and the loss of DTH. In HPV-associated cancers the E6/E7 genes are expressed and an antibody response to the proteins is found in at least 50% of cases indicating that these oncoproteins are potential targets for immunotherapy.
Southey A, Sleeman DPS, Lloyd K, Dalley D, Chambers MA, Hewinson RG, Gormley E (2001) Immunological responses of Eurasian badgers (Meles meles) vaccinated with Mycobacterium bovis BCG (bacillus calmette guerin), VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 79 (3-4) pp. 197-207 ELSEVIER SCIENCE BV
King DR, Mutukwa N, Lesellier S, Cheeseman C, Chambers MA, Banks M (2004) Detection of mustelid herpesvirus-1 infected European badgers (Meles meles) in the British Isles., J Wildl Dis 40 (1) pp. 99-102
The aim of this study was to assess the frequency of mustelid herpesvirus-1 (MusHV-1) infection in free-ranging badgers (Meles meles) in the British Isles. A polymerase chain reaction assay was developed that detected MusHV-1 DNA in 95% (18/19) and 100% (10/10) of anticoagulant-treated blood samples collected from free-ranging badgers sampled in the southwest of England and the Republic of Ireland, respectively. An indirect immunoassay was also developed to detect MusHV-1-specific immunoglobulin-G in serum samples. Using an arbitrary cutoff of twice the optical density obtained with a virus-negative preparation, 32.7% (36/110) of sera sampled from badgers were positive. The conclusion drawn from these data is that infection with MusHV-1 is common among free-ranging badgers in the British Isles.
Canfield PJ, Day MJ, Gavier-Widen D, Hewinson RG, Chambers MA (2002) Immunohistochemical characterization of tuberculous and non-tuberculous lesions in naturally infected European badgers (Meles meles), JOURNAL OF COMPARATIVE PATHOLOGY 126 (4) pp. 254-264 ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD
Greenwald R, Esfandiari J, Lesellier S, Houghton R, Pollock J, Aagaard C, Andersen P, Hewinson RG, Chambers M, Lyashchenko K (2003) Improved serodetection of Mycobacterium bovis infection in badgers (Meles meles) using multiantigen test formats, DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE 46 (3) pp. 197-203 ELSEVIER SCIENCE INC
Chambers MA, Waterhouse S, Lyashchenko K, Delahay R, Sayers R, Hewinson RG (2009) Performance of TB immunodiagnostic tests in Eurasian badgers (Meles meles) of different ages and the influence of duration of infection on serological sensitivity, Bmc Veterinary Research 5
Background: In parts of Great Britain and Ireland, Eurasian badgers (Meles meles) constitute a reservoir of Mycobacterium bovis infection and a potential source of infection for cattle. In vitro diagnostic tests for live badgers are an important component of strategies to control TB in this species. Immunological tests have been developed for badgers, although little is known about the influence of the age of the animal on test performance. To address this, we evaluated the performance of three immunological tests for badgers with respect to the age of the animal: the Brock Test and BrockTB STAT-PAK (R) serological tests and the recently developed interferon-gamma enzyme immunoassay (IFN gamma EIA). Data published elsewhere suggested that seropositivity was associated with more progressive forms of TB in the badger. To gain further evidence for this, we used longitudinal data from a well-studied population of badgers to test for an association between the sensitivity of the Brock Test and the duration of TB infection. Results: Sensitivity of the two serological tests was approximately 54% for both cubs and adults. Sensitivity of the IFN gamma EIA was lower in cubs (57%) compared with adults (85%) when a common cut-off value was used to define test positivity. Taking data from the cubs alone, the IFN gamma EIA cut-off value could be adjusted to increase the sensitivity to 71% with no loss in specificity. As a general observation, specificity of all tests was higher in cubs, although only significantly so in the case of the Brock Test. Using logistic regression analysis to adjust for age, sensitivity of the Brock Test was significantly lower at first culture positive event (58%), but increased to >80% as infection progressed. Conclusion: These data suggest that serodiagnosis could be a valuable tool for detecting a higher proportion of badgers with the greatest probability of transmitting infection. The age category of the badger appeared to exert little influence on the performance of the serological tests. Although data were only available for the IFN gamma EIA in a small number of cubs, reduced sensitivity of the test in these individuals suggests a lower cut-off may be needed when testing younger animals.
Chambers MA, Williams A, Hatch G, Gavier-Widén D, Hall G, Huygen K, Lowrie D, Marsh PD, Hewinson RG (2002) Vaccination of guinea pigs with DNA encoding the mycobacterial antigen MPB83 influences pulmonary pathology but not hematogenous spread following aerogenic infection with Mycobacterium bovis., Infect Immun 70 (4) pp. 2159-2165
Protection of cattle against bovine tuberculosis by vaccination could be an important control strategy in countries where there is persistent Mycobacterium bovis infection in wildlife and in developing countries where it is not economical to implement a tuberculin test and slaughter control program. The main aim of such a vaccination strategy would be to reduce transmission of infection by reducing the lung pathology caused by infection and preventing seeding of the organism to organs from which M. bovis could be excreted. Recent reports of successful DNA vaccination against Mycobacterium tuberculosis in small-animal models have suggested that DNA vaccines act by reducing lung pathology without sensitizing animals to tuberculin testing. We therefore evaluated the ability of vaccines consisting of DNA encoding the mycobacterial antigens MPB83 and 85A to reduce lung pathology and prevent hematogenous spread in guinea pigs challenged with a low dose of aerosolized M. bovis. Vaccination with MPB83 DNA reduced the severity of pulmonary lesions, as assessed by histopathology, and resembled M. bovis BCG vaccination in this respect. However, unlike BCG vaccination, MPB83 DNA vaccination did not protect challenged guinea pigs from hematogenous spread of organisms to the spleen. In contrast, vaccination with antigen 85A DNA, a promising DNA vaccine for human tuberculosis, had no measurable protective effect against infection with M. bovis.
Tomlinson AJ, Chambers MA, Wilson GJ, McDonald RA, Delahay RJ (2013) Sex-Related Heterogeneity in the Life-History Correlates of Mycobacterium bovis Infection in European Badgers (Meles meles), Transbound Emerg Dis 60 Suppl 1 pp. 37-45
Heterogeneity in the progression of disease amongst individual wild animals may impact on both pathogen and host dynamics at the population level, through differential effects on transmission, mortality and reproductive output. The role of the European badger (Meles meles) as a reservoir host for Mycobacterium bovis infection in the UK and Ireland has been the focus of intense research for many years. Here, we investigate life-history correlates of infection in a high-density undisturbed badger population naturally infected with M. bovis. We found no evidence of a significant impact of M. bovis infection on female reproductive activity or success, with evidence of reproduction continuing successfully for several years in the face of M. bovis excretion. We also found evidence to support the hypothesis that female badgers are more resilient to established M. bovis infection than male badgers, with longer survival times following the detection of bacterial excretion. We discuss the importance of infectious breeding females in the persistence of M. bovis in badger populations, and how our findings in male badgers are consistent with testosterone-induced immunosuppression. In addition, we found significant weight loss in badgers with evidence of disseminated infection, based on the culture of M. bovis from body systems other than the respiratory tract. For females, there was a gradual loss of weight as infection progressed, whereas males only experienced substantial weight loss when infection had progressed to the point of dissemination. We discuss how these differences may be explained in terms of resource allocation and physiological trade-offs.
Knobloch H, Turner C, Spooner A, Chambers M (2009) Methodological Variability Using Electronic Nose Technology For Headspace Analysis, OLFACTION AND ELECTRONIC NOSE, PROCEEDINGS 1137 pp. 327-330 AMER INST PHYSICS
Chambers MA, Whelan AO, Spallek R, Singh M, Coddeville B, Guerardel Y, Elass E (2010) Non-acylated Mycobacterium bovis glycoprotein MPB83 binds to TLR1/2 and stimulates production of matrix metalloproteinase 9, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 400 (3) pp. 403-408 ACADEMIC PRESS INC ELSEVIER SCIENCE
Knobloch H, Turner C, Spooner A, Chambers M (2009) Methodological variation in headspace analysis of liquid samples using electronic nose, SENSORS AND ACTUATORS B-CHEMICAL 139 (2) pp. 353-360 ELSEVIER SCIENCE SA
Blancou J, Artois M, Gilot-Fromont E, Kaden V, Rossi S, Smith GC, Hutchings MR, Chambers MA, Houghton S, Delahay RJ (2009) Options for the control of disease 1: Targeting the infectious or parasitic agent, In: Management of Disease in Wild Mammals pp. 97-120
There are three basic approaches to managing diseases: directly reduce the reproductive rate of the pathogen, reduce host (or infected host) density, or manipulate the environment to reduce contact between diseased and susceptible animals. In this chapter we will look at the first of these approaches. Since disease transmission results from direct or indirect contact between infectious and susceptible individuals, there are two ways to target an infectious agent: either limit the number of susceptible individuals by vaccinating them, or treat infected individuals in order to reduce the duration or intensity of the infectious period and the number of infectious individuals present at any given time. The overall aim of this chapter is to consider the conditions under which vaccination and treatment may make a valuable contribution to the control of infectious diseases in wild mammal populations. Both field research and mathematical modelling approaches have been used to address this question. For vaccination, early mathematical models of infectious disease dynamics suggested a simple answer: vaccination is useful as soon as the rate of control ensures that a sufficient proportion of the population is immune for a sufficient period of time (Bailey 1957). At the individual level, this herd immunity means that any given infectious individual has a low probability of encountering a susceptible animal. If the disease is introduced into a vaccinated population, the mean number of secondary infections caused by each infected case will be lower than unity, thus preventing further outbreaks from occurring (R <: see Chapter 3). However, this generalised scenario may be considered overly simplistic, as the practicalities of vaccination campaigns often complicate matters. For example, modelling studies often include assumptions about perfect vaccine efficacy, and the efficiency of delivering the vaccine to a population that may or may not reflect the situation in the field. © Springer 2009.
Lesellier S, Corner L, Costello E, Sleeman P, Lyashchenko KP, Greenwald R, Esfandiari J, Hewinson RG, Chambers M, Gormley E (2009) Immunological responses following experimental endobronchial infection of badgers (Metes meles) with different doses of Mycobacterium bovis, VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 127 (1-2) pp. 174-180 ELSEVIER SCIENCE BV
Delahay RJ, Walker N, Smith GS, Wilkinson D, Clifton-Hadley RS, Cheeseman CL, Tomlinson AJ, Chambers MA (2013) Erratum: Long-term temporal trends and estimated transmission rates for Mycobacterium bovis infection in an undisturbed high-density badger (Meles meles) population (Epidemiology and Infection (2013) DOI: 10.1017/ S0950268813000721), Epidemiology and Infection 141 (7)
Corner LAL, Costello E, O'Meara D, Lesellier S, Aldwell FE, Singh M, Hewinson RG, Chambers MA, Gormley E (2010) Oral vaccination of badgers (Meles meles) with BCG and protective immunity against endobronchial challenge with Mycobacterium bovis, VACCINE 28 (38) pp. 6265-6272 ELSEVIER SCI LTD
Sawyer J, Mealing D, Dalley D, Dave D, Lesellier S, Palmer S, Bowen-Davies J, Crawshaw TR, Chambers MA (2007) Development and evaluation of a test for tuberculosis in live European badgers (Meles meles) based on measurement of gamma interferon mRNA by real-time PCR, JOURNAL OF CLINICAL MICROBIOLOGY 45 (8) pp. 2398-2403 AMER SOC MICROBIOLOGY
Chambers MA (2010) Transcutaneous immunization with lipid offers a new route of vaccination against Helicobacter pylori and a new candidate delivery vehicle, EXPERT REVIEW OF VACCINES 9 (3) pp. 249-253 EXPERT REVIEWS
Dalley D, Davé D, Lesellier S, Palmer S, Crawshaw T, Hewinson RG, Chambers M (2008) Development and evaluation of a gamma-interferon assay for tuberculosis in badgers (Meles meles)., Tuberculosis (Edinb) 88 (3) pp. 235-243
In this paper we report the development of a sensitive and specific assay for the detection of tuberculosis (TB) in European badgers (Meles meles), based on the stimulation of lymphocytes in whole-blood culture and the subsequent detection of gamma-interferon (IFNgamma) by sandwich ELISA. The comparative levels of IFNgamma produced to bovine and avian tuberculin (B-A) was used as the basis of determining the TB status of badgers, resulting in a more sensitive test than that based on the defined Mycobacterium bovis antigens ESAT6 and CFP10. The assay was evaluated using 235 badgers. The IFNgamma EIA (enzyme immunoassay) based on a monoclonal pair (mEIA) was more sensitive than one using a rabbit polyclonal antiserum (pEIA). At a specificity of 93.6%, the mEIA was 80.9% sensitive, compared to a sensitivity of 74.5% for the pEIA. At the same specificity as the EIA, the current serological ELISA test for TB in badgers (Brock test) had a sensitivity of 48.9%. Only one of the culture positive badgers missed by the mEIA was correctly diagnosed by the Brock test, suggesting that the combination of both a T-cell and serological test has little diagnostic advantage.
Chambers M, Dougan G, Newman J, Brown F, Crowther J, Mould AP, Humphries MJ, Francis MJ, Clarke B, Brown AL, Rowlands D (1996) Erratum: Chimeric hepatitis B virus core particles as probes for studying peptide-integrin interactions (Journal of Virology (1994) 70:6 (4045-4052)), Journal of Virology 70 (8)
Whelan AO, Wright DC, Chambers MA, Singh M, Hewinson RG, Vordermeier HM (2008) Evidence for enhanced central memory priming by live Mycobacterium bovis BCG vaccine in comparison with killed BCG formulations., Vaccine 26 (2) pp. 166-173
Development of cattle vaccines against bovine tuberculosis is a GB research priority. Recently, it has been shown that formalin-killed Bacille Calmette-Guérin (BCG) delivered with the liposomal adjuvant NAX687 imparted significant protection against Mycobacterium bovis infection in the guinea pig aerosol infection model. Extending these studies, we inoculated calves with live BCG, formalin-killed BCG and formalin-killed BCG formulated in NAX687. Live and killed BCG vaccine formulations induced primary effector T-cell populations comparably, both killed BCG formulations also induced potent humoral immune responses. In contrast, live BCG generated enhanced central memory responses against the protective antigen Ag85A whilst killed BCG-induced such responses only poorly. However, the poor capacity of killed BCG to generate central memory could be partially overcome by formulation with NAX687. Measurement of central memory responses induced by TB vaccine candidates in cattle may provide a useful correlate of protection and warrants further investigation in challenge experiments.
Chambers MA, Crawshaw T, Waterhouse S, Delahay R, Hewinson RG, Lyashchenko KP (2008) Validation of the BrockTB stat-pak assay for detection of tuberculosis in Eurasian badgers (Meles meles) and influence of disease severity on diagnostic accuracy, JOURNAL OF CLINICAL MICROBIOLOGY 46 (4) pp. 1498-1500 AMER SOC MICROBIOLOGY
Chambers MA, Jahans K, Whelan A, Hughes C, Sayers R, Perkins A, Glyn Hewinson R (2002) Simple objective measurement of the cutaneous delayed-type hypersensitivity reaction to tuberculin using spectrophotometry., Skin Res Technol 8 (2) pp. 89-93
BACKGROUND/AIMS: A number of subjective methods have been used to quantify the extent of the cutaneous delayed-type hypersensitivity (DTH) reaction. However, because of their subjective nature, significant differences in measurements may be seen between individual observers or laboratories unless thorough training is given to each observer. METHODS: Objective measurement of the DTH reaction using a hand-held spectrophotometer is described. Guinea pigs were primed using inoculation with Mycobacterium bovis Bacille Calmette-Guerin and challenged five weeks later in the shaved flank with three doses of bovine purified protein derivative. The extent of the ensuing DTH reaction was measured 24 and 48 h later. Spectrophotometric measurement of the reaction site was compared with a control region of skin on each animal and expressed as the change within a standard colour space. Data obtained with the spectrophotometer was compared with the subjective measurement of the area of the DTH reaction by an experienced operator. RESULTS: The measurements obtained with the spectrophotometer correlated very closely with conventional measurement of the reaction area by a trained operator. The reaction size in square mm and changes along the red/green colour axis was correlated most strongly. CONCLUSION: Spectrophotometric measurement of the DTH reaction had advantages over conventional measuring techniques in terms of speed, reproducibility and reduced operator to operator variation. We conclude that the cutaneous DTH reaction may be simply and objectively quantified with the use of a hand-held spectrophotometer.
Salguero FJ, Richard A, Gough J, Long A, Weyer U, Cooley WA, Chambers MA, Lesellier S (2010) Pelioid Hepatocellular Carcinoma in an Adult Eurasian Badger (Meles meles), JOURNAL OF COMPARATIVE PATHOLOGY 142 (2-3) pp. 208-212 ELSEVIER SCI LTD
Chambers MA, Williams A, Gavier-Widén D, Whelan A, Hughes C, Hall G, Lever MS, Marsh PD, Hewinson RG (2001) A guinea pig model of low-dose Mycobacterium bovis aerogenic infection., Vet Microbiol 80 (3) pp. 213-226
In order to develop a model of Mycobacterium bovis infection with pathogenetical relevance, a modified version of the Henderson apparatus was used to deliver infectious aerosols directly to the snouts of guinea pigs. Aerosols generated from 10(6), 10(7), 10(8)CFU/ml M. bovis suspensions established disease in every animal, with estimated retained doses of 10, 100, 1000 CFU, respectively. For comparison, other guinea pigs were inoculated with 100 CFU M. bovis intramuscularly (i.m.). Pathology and bacterial colonisation of lungs and spleen varied according to the dose and route of inoculation. Animals inoculated i.m. gave a significant cutaneous tuberculin hypersensitivity reaction earlier after testing than those infected aerogenically. A serological response to M. bovis antigens was detected in all infected animals. Intensity of antigen recognition was dose-dependent and although the range of antigens recognised varied between animals, a 25 kDa antigen present in the cell fraction was serodominant. Thus, a reproducible guinea pig model has been defined that may be suitable for virulence, vaccination, and immunological studies.
Tomlinson A, Chambers M, Delahay R (2012) Mycobacterium bovis infection in badger cubs: Re-assessing the evidence for maternally derived immunological protection from advanced disease, VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY 148 (3-4) pp. 326-330 ELSEVIER SCIENCE BV
Xue T, Stavropoulos E, Yang M, Ragno S, Vordermeier M, Chambers M, Hewinson G, Lowrie DB, Colston MJ, Tascon RE (2004) RNA encoding the MPT83 antigen induces protective immune responses against Mycobacterium tuberculosis infection, INFECTION AND IMMUNITY 72 (11) pp. 6324-6329 AMER SOC MICROBIOLOGY
Accurate detection of infection with Mycobacterium bovis in live badgers would enable targeted tuberculosis control. Practical challenges in sampling wild badger populations mean that diagnosis of infection at the group (rather than the individual) level is attractive. We modelled data spanning 7 years containing over 2000 sampling events from a population of wild badgers in southwest England to quantify the ability to correctly identify the infection status of badgers at the group level. We explored the effects of variations in: (1) trapping efficiency; (2) prevalence of M. bovis; (3) using three diagnostic tests singly and in combination with one another; and (4) the number of badgers required to test positive in order to classify groups as infected. No single test was able to reliably identify infected badger groups if 80% sensitive, at least 94% specific, and able to be performed rapidly in the field.
Clark S, Cross ML, Nadian A, Vipond J, Court P, Williams A, Hewinson RG, Aldwell FE, Chambers MA (2008) Oral vaccination of guinea pigs with a mycobacterium bovis bacillus Calmette-Guerin vaccine in a lipid matrix protects against aerosol infection with virulent M. bovis, INFECTION AND IMMUNITY 76 (8) pp. 3771-3776 AMER SOC MICROBIOLOGY
Chambers MA, Wright DC, Brisker J, Williams A, Hatch G, Gavier-Widén D, Hall G, Marsh PD, Glyn Hewinson R (2004) A single dose of killed Mycobacterium bovis BCG in a novel class of adjuvant (Novasome) protects guinea pigs from lethal tuberculosis., Vaccine 22 (8) pp. 1063-1071
The only vaccine currently available for the prevention of tuberculosis in man is a live attenuated vaccine, bacille Calmette-Guerin (BCG), derived from Mycobacterium bovis. Concerns over the lack of the universal efficacy and safety of BCG have resulted in efforts to develop a new generation of TB vaccines. Historically, killed whole-cell preparations of mycobacteria have been ineffective vaccines. We revisited the potential of killed whole-cell vaccines by comparing their efficacy with live BCG Pasteur in a guinea pig challenge model. BCG Pasteur was inactivated with a low concentration of formalin and showed to be non-viable in culture or severe combined immunodeficient mice. Formalin-inactivated BCG was mixed with non-phospholipid liposome adjuvants (Novasomes) and administered to guinea pigs as a single subcutaneous inoculation. All formulations were well tolerated and one conferred a significant survival advantage against lethal aerogenic challenge with M. bovis.
Clark S, Cross ML, Smith A, Court P, Vipond J, Nadian A, Hewinson RG, Batchelor HK, Perrie Y, Williams A, Aldwell FE, Chambers MA (2008) Assessment of different formulations of oral Mycobacterium bovis Bacille Calmette-Guerin (BCG) vaccine in rodent models for immunogenicity and protection against aerosol challenge with M-bovis, VACCINE 26 (46) pp. 5791-5797 ELSEVIER SCI LTD
Cui H, Li S, Yuan Q, Wadhwa A, Eda S, Chambers M, Ashford R, Jiang H, Wu J (2013) An AC electrokinetic impedance immunosensor for rapid detection of tuberculosis, ANALYST 138 (23) pp. 7188-7196 ROYAL SOC CHEMISTRY
Gowtage-Sequeira S, Paterson A, Lyashchenko KP, Lesellier S, Chambers MA (2009) Evaluation of the CervidTB STAT-PAK for the Detection of Mycobacterium bovis Infection in Wild Deer in Great Britain, CLINICAL AND VACCINE IMMUNOLOGY 16 (10) pp. 1449-1452 AMER SOC MICROBIOLOGY
Gavier-Widen D, Cooke MM, Gallagher J, Chambers MA, Gortazar C (2009) A review of infection of wildlife hosts with Mycobacterium bovis and the diagnostic difficulties of the 'no visible lesion' presentation, NEW ZEALAND VETERINARY JOURNAL 57 (3) pp. 122-131 TAYLOR & FRANCIS LTD
Lesellier S, Palmer S, Gowtage-Sequiera S, Ashford R, Dalley D, Dave D, Weyer U, Salguero FJ, Nunez A, Crawshaw T, Corner LAL, Hewinson RG, Chambers MA (2011) Protection of Eurasian badgers (Meles meles) from tuberculosis after intra-muscular vaccination with different doses of BCG, VACCINE 29 (21) pp. 3782-3790 ELSEVIER SCI LTD
Chambers MA, Williams A, Gavier-Widén D, Whelan A, Hall G, Marsh PD, Bloom BR, Jacobs WR, Hewinson RG (2000) Identification of a Mycobacterium bovis BCG auxotrophic mutant that protects guinea pigs against M. bovis and hematogenous spread of Mycobacterium tuberculosis without sensitization to tuberculin., Infect Immun 68 (12) pp. 7094-7099
Tuberculosis remains one of the most significant diseases of humans and animals. The only currently available vaccine against this disease is a live, attenuated vaccine, bacillus Calmette-Guérin (BCG), which was originally derived from Mycobacterium bovis and despite its variable efficacy is the most widely administered vaccine in the world. With the advent of the human immunodeficiency virus-AIDS pandemic concern has been raised over the safety of BCG. Moreover, since BCG sensitizes vaccinated individuals to the tuberculin test, vaccination with BCG prevents diagnosis of infection in vaccinated individuals. Recently, auxotrophic strains of BCG have been generated by insertional mutagenesis which have been shown to be safer than the parent BCG strain following administration to mice with severe combined immunodeficiency disease. These strains have also been shown to give comparable protection against intravenous and intratracheal challenge of BALB/c mice with M. tuberculosis relative to conventional BCG. Here we report that one of these mutants, a leucine auxotroph of BCG, conferred significant protection of the lungs and spleens of guinea pigs infected with M. bovis and protection of the spleens of guinea pigs infected with M. tuberculosis in the absence of a cutaneous hypersensitivity reaction to tuberculin. Therefore, protective immunity to tuberculosis may, at least in part, be achieved without sensitization to the tuberculin skin test. These results indicate that it may be possible to develop a new generation of vaccines based on BCG that are protective, are safe for use in the immunocompromised, and do not preclude the use of the tuberculin skin test in both humans and animals.
Hogarth PJ, Jahans KJ, Hecker R, Hewinson RG, Chambers MA (2003) Evaluation of adjuvants for protein vaccines against tuberculosis in guinea pigs., Vaccine 21 (9-10) pp. 977-982
Subunit vaccines against tuberculosis show promise but require administration with adjuvants to stimulate relevant immune responses for protection. Guinea pigs are the model of choice for evaluating protective immunity to aerogenic challenge with virulent mycobacteria, but few studies have been undertaken to identify suitable adjuvants for vaccine screening in this species. Here, we compare the efficacy of several adjuvants to induce T cell responses to culture filtrate protein in guinea pigs. We report that of several adjuvants tested, the most promising was CpG ODN formulated in an aqueous emulsion. This adjuvant induced type 1 T cell responses equivalent to that of FIA, as measured by delayed-type hypersensitivity reactions (DTH), antigen-specific T cell proliferation and antigen-specific IgG1 and IgG2 responses. These data demonstrate the potential for CpG motif based adjuvants for use in TB vaccine screening in guinea pigs, and other diseases where a type 1 T cell response is required.
Murphy D, Costello E, Aldwell FE, Lesellier S, Chambers MA, Fitzsimons T, Corner LAL, Gormley E (2014) Oral vaccination of badgers (Meles meles) against tuberculosis: Comparison of the protection generated by BCG vaccine strains Pasteur and Danish, Veterinary Journal 200 (3) pp. 362-367
Vaccination of badgers by the subcutaneous, mucosal and oral routes with the Pasteur strain of Mycobacterium bovis bacille Calmette-Guérin (BCG) has resulted in significant protection against experimental infection with virulent M.bovis. However, as the BCG Danish strain is the only commercially licensed BCG vaccine for use in humans in the European Union it is the vaccine of choice for delivery to badger populations. As all oral vaccination studies in badgers were previously conducted using the BCG Pasteur strain, this study compared protection in badgers following oral vaccination with the Pasteur and the Danish strains.Groups of badgers were vaccinated orally with 108 colony forming units (CFU) BCG Danish 1331 (n = 7 badgers) or 108 CFU BCG Pasteur 1173P2 (n = 6). Another group (n = 8) served as non-vaccinated controls. At 12 weeks post-vaccination, the animals were challenged by the endobronchial route with 6 × 103 CFU M.bovis, and at 15 weeks post-infection, all of the badgers were euthanased. Vaccination with either BCG strain provided protection against challenge compared with controls. The vaccinated badgers had significantly fewer sites with gross pathology and significantly lower gross pathological severity scores, fewer sites with histological lesions and fewer sites of infection, significantly lower bacterial counts in the thoracic lymph node, and lower bacterial counts in the lungs than the control group. No differences were observed between either of the vaccine groups by any of the pathology and bacteriology measures. The ELISPOT analysis, measuring production of badger interferon - gamma (IFN-³), was also similar across the vaccinated groups. © 2014 Elsevier Ltd.
Balseiro A, González-Quirós P, Rodríguez O, Francisca Copano M, Merediz I, de Juan L, Chambers MA, Delahay RJ, Marreros N, Royo LJ, Bezos J, Prieto JM, Gortázar C (2013) Spatial relationships between Eurasian badgers (Meles meles) and cattle infected with Mycobacterium bovis in Northern Spain, Vet J
Recent studies suggest that badgers may be a potential reservoir of Mycobacterium bovis infection for cattle in Northern Spain. The objective of this study was to investigate potential epidemiological links between cattle and badgers. Culture and molecular typing data were available for cattle culled during the national tuberculosis (TB) eradication campaigns between 2008 and 2012, as well as from 171 necropsied badgers and 60 live animals trapped and examined over the same time period. Mycobacterium tuberculosis complex strains were isolated from pooled tissues of 14 (8.2%) necropsied badgers, of which 11 were identified as M. bovis: six different spoligotypes of M. bovis were subsequently identified. In two geographical locations where these isolates were shared between cattle and badgers, infected cattle herds and badgers lived in close contact. Although it remains unclear if badgers are a maintenance or spill-over host of M. bovis in this setting, it would appear prudent to have precautionary measures in place to reduce contact between cattle and badgers.
Turner C, Knobloch H, Richards J, Richards P, Mottram TTF, Marlin D, Chambers MA (2012) Development of a device for sampling cattle breath, BIOSYSTEMS ENGINEERING 112 (2) pp. 75-81 ACADEMIC PRESS INC ELSEVIER SCIENCE
Saleem IY, Vordermeier M, Chambers MA, Coombes AGA (2000) Improving the sensitivity of polypeptide-based diagnostic assays, Journal of Pharmacy and Pharmacology 52 (9 SUPPL.)
Chambers MA, Vordermeier H, Whelan A, Commander N, Tascon R, Lowrie D, Hewinson RG (2000) Vaccination of mice and cattle with plasmid DNA encoding the Mycobacterium bovis antigen MPB83., Clin Infect Dis 30 Suppl 3 pp. S283-S287
A scientific review of bovine tuberculosis in Great Britain has concluded that the development of a cattle vaccine holds the best prospect for long-term disease control. Recent reports of successful DNA vaccination against Mycobacterium tuberculosis in small animal models have raised the possibility of using a similar strategy to produce vaccines against Mycobacterium bovis infection in cattle. To test this possibility, BALB/c mice were immunized with DNA encoding the M. bovis antigen MPB83. The mice responded to vaccination with a mixed IgG1/IgG2a response to the antigen and were protected from intravenous challenge with virulent M. bovis to a similar extent as those vaccinated with bacille Calmette-Guérin. The immunogenicity of the DNA vaccine in cattle was tested, after having established that DNA encoding MPB83 was immunogenic and elicited protective immunity in mice. In these studies, vaccinated animals had strong proliferative responses to MPB83.
Hill SC, Murphy AA, Cotten M, Palser AL, Benson P, Lesellier S, Gormley E, Richomme C, Grierson S, Bhuachalla DN, Chambers M, Kellam P, Boschiroli ML, Ehlers B, Jarvis MA, Pybus OG (2015) Discovery of a polyomavirus in European badgers (Meles meles) and the evolution of host range in the family Polyomaviridae., J Gen Virol 96 (Pt 6) pp. 1411-1422
Polyomaviruses infect a diverse range of mammalian and avian hosts, and are associated with a variety of symptoms. However, it is unknown whether the viruses are found in all mammalian families and the evolutionary history of the polyomaviruses is still unclear. Here, we report the discovery of a novel polyomavirus in the European badger (Meles meles), which to our knowledge represents the first polyomavirus to be characterized in the family Mustelidae, and within a European carnivoran. Although the virus was discovered serendipitously in the supernatant of a cell culture inoculated with badger material, we subsequently confirmed its presence in wild badgers. The European badger polyomavirus was tentatively named Meles meles polyomavirus 1 (MmelPyV1). The genome is 5187 bp long and encodes proteins typical of polyomaviruses. Phylogenetic analyses including all known polyomavirus genomes consistently group MmelPyV1 with California sea lion polyomavirus 1 across all regions of the genome. Further evolutionary analyses revealed phylogenetic discordance amongst polyomavirus genome regions, possibly arising from evolutionary rate heterogeneity, and a complex association between polyomavirus phylogeny and host taxonomic groups.
Knobloch H, Turner C, Chambers M, Reinhold P (2009) Serum Headspace Analysis With An Electronic Nose And Comparison With Clinical Signs Following Experimental Infection Of Cattle With Mannheimia Haemolytica, OLFACTION AND ELECTRONIC NOSE, PROCEEDINGS 1137 pp. 439-442 AMER INST PHYSICS
Murphy D, Costello E, Aldwell FE, Lesellier S, Chambers MA, Fitzsimons T, Corner LA, Gormley E (2014) Oral vaccination of badgers (Meles meles) against tuberculosis: comparison of the protection generated by BCG vaccine strains Pasteur and Danish., Vet J 200 (3) pp. 362-367
Vaccination of badgers by the subcutaneous, mucosal and oral routes with the Pasteur strain of Mycobacterium bovis bacille Calmette-Guérin (BCG) has resulted in significant protection against experimental infection with virulent M. bovis. However, as the BCG Danish strain is the only commercially licensed BCG vaccine for use in humans in the European Union it is the vaccine of choice for delivery to badger populations. As all oral vaccination studies in badgers were previously conducted using the BCG Pasteur strain, this study compared protection in badgers following oral vaccination with the Pasteur and the Danish strains. Groups of badgers were vaccinated orally with 10(8) colony forming units (CFU) BCG Danish 1331 (n = 7 badgers) or 10(8) CFU BCG Pasteur 1173P2 (n = 6). Another group (n = 8) served as non-vaccinated controls. At 12 weeks post-vaccination, the animals were challenged by the endobronchial route with 6 × 10(3) CFU M. bovis, and at 15 weeks post-infection, all of the badgers were euthanased. Vaccination with either BCG strain provided protection against challenge compared with controls. The vaccinated badgers had significantly fewer sites with gross pathology and significantly lower gross pathological severity scores, fewer sites with histological lesions and fewer sites of infection, significantly lower bacterial counts in the thoracic lymph node, and lower bacterial counts in the lungs than the control group. No differences were observed between either of the vaccine groups by any of the pathology and bacteriology measures. The ELISPOT analysis, measuring production of badger interferon - gamma (IFN-³), was also similar across the vaccinated groups.
STANLEY M, CHAMBERS M (1993) A DELAYED-TYPE HYPERSENSITIVITY RESPONSE TO HUMAN PAPILLOMAVIRUS TYPE-16 (HPV16) PROTEINS, JOURNAL OF CELLULAR BIOCHEMISTRY pp. 112-112
Robertson A, Chambers MA, Delahay RJ, McDonald RA, Palphramand KL, Rogers F, Carter SP (2015) Exposure of nontarget wildlife to candidate TB vaccine baits deployed for European badgers, European Journal of Wildlife Research 61 (2) pp. 263-269
© 2015, Springer-Verlag Berlin Heidelberg.In the UK and Republic of Ireland, the European badger Meles meles is considered a maintenance host for bTB and is involved in transmission of infection to cattle. A badger vaccine delivered in an oral bait is currently under development as part of an ongoing effort to reduce levels of disease in the badger population. An oral vaccine would likely be deployed in close vicinity to badger burrows (setts), such that bait will most likely be taken by the target species. However, a range of nontarget species may also occur close to badger setts, and some may potentially interfere with or consume baits. In this study, we used surveillance cameras to record the presence of nontarget species at 16 badger setts involved in a bait deployment study in southwest England. We recorded significant levels of nontarget species activity close to badger setts. The most commonly observed species were small rodents, which were observed at all setts, and in some cases accounted for >90 % of nontarget species observations. A total of 11 other nontarget species were also observed, indicating that a broad range of species may potentially come into contact with vaccine baits deployed at badger setts. Although the majority of these species were not observed interacting directly with baits, small rodents and squirrels were observed eating baits in a number of instances. In addition, monitoring of bait disappearance at 24 setts indicated that small rodents may take >30 % of bait deployed at some setts. The implications for the deployment of an oral vaccine for badgers are discussed.
ZHU M, GOUGH M, PATEL P, BANKS R, CHAMBERS M, SELBY P, JACKSON A (1996) Engineering mycobacteria to express IL-15, IMMUNOLOGY 89 pp. B15-B15
Chambers MA, Rogers F, Delahay RJ, Lesellier S, Ashford R, Dalley D, Gowtage S, Dave D, Palmer S, Brewer J, Crawshaw T, Clifton-Hadley R, Carter S, Cheeseman C, Hanks C, Murray A, Palphramand K, Pietravalle S, Smith GC, Tomlinson A, Walker NJ, Wilson GJ, Corner LAL, Rushton SP, Shirley MDF, Gettinby G, McDonald RA, Hewinson RG (2011) Bacillus Calmette-Guerin vaccination reduces the severity and progression of tuberculosis in badgers, PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 278 (1713) pp. 1913-1920 ROYAL SOC
In the UK and the Republic of Ireland, the European badger (Meles meles) is a maintenance host for Mycobacterium bovis, and may transmit the infection to cattle causing bovine tuberculosis (TB). Vaccination of badgers using an injectable Bacillus Calmette-Guerin (BCG) vaccine is undertaken in some areas of the UK with the intention of interrupting this transmission, and vaccination research is underway in Ireland. An oral badger TB vaccine is also under development. We investigated the behaviour of badgers and non-target wildlife species towards three candidate baits being considered for delivering BCG to badgers orally. Bait preference was investigated by recording removal rates of baits and through the use of video surveillance at 16 badger setts. We found high variation in rates of bait removal by badgers among setts but no significant differences in removal rates among bait types or in preference behaviour from video footage. Variation in bait removal among setts correlated with the number of nights on which badgers were seen at the sett, with most baits being removed where badgers were seen on >50% of nights during the ten-day study period. Relatively few baits were removed at setts with low levels of recorded badger activity. Monitoring badger activity prior to bait deployment may therefore be useful in increasing bait uptake and vaccine coverage. Bait removal by badgers increased over the ten-day study period, suggesting initial neophobic behaviour at some setts and that a period of ?pre-feeding? may be required prior to vaccine deployment. Our results indicate that all three candidate baits are attractive to badgers. Removal of baits by non-target wildlife species was generally low, but varied among bait types, with smaller baits in packaging less likely to be removed. Enclosing baits in packaging is likely to deter non-target species, although in some cases non-target species did remove up to 13% of packaged baits.
Gowtage S, Williams G, Henderson R, Aylett P, MacMorran D, Palmer S, Robertson A, Lesellier S, Carter S, Chambers M (2017) Testing of a palatable bait and compatible vaccine carrier for the oral vaccination of European badgers (Meles meles) against tuberculosis,Vaccine 35 (6) pp. 987-992
The oral vaccination of wild badgers (Meles meles) with live Bacillus Calmette?Guérin (BCG) is one of the tools being considered for the control of bovine tuberculosis (caused by Mycobacterium bovis) in the UK. The design of a product for oral vaccination requires that numerous, and often competing, conditions are met. These include the need for a highly palatable, but physically stable bait that will meet regulatory requirements, and one which is also compatible with the vaccine formulation; in this case live BCG. In collaboration with two commercial bait companies we have developed a highly attractive and palatable bait recipe designed specifically for European badgers (Meles meles) that meets these requirements. The palatability of different batches of bait was evaluated against a standardised palatable control bait using captive badgers. The physical properties of the bait are described e.g. firmness and colour. The microbial load in the bait was assessed against European and US Pharmacopoeias. The bait was combined with an edible vaccine carrier made of hydrogenated peanut oil in which BCG vaccine was stable during bait manufacture and cold storage, demonstrating <0.5 log10 reduction in titre after 117 weeks? storage at ?20 °C. BCG stability in bait was also evaluated at +4 °C and under simulated environmental conditions (20 °C, 98% Relative Humidity; RH). Finally, iophenoxic acid biomarkers were utilised as a surrogate for the BCG vaccine, to test variants of the vaccine-bait design for their ability to deliver biomarker to the gastrointestinal tract of individual animals. These data provide the first detailed description of a bait-vaccine delivery system developed specifically for the oral vaccination of badgers against Mycobacterium bovis using live BCG.
One of the major transmission routes for the foodborne bacterial pathogen Campylobacter is undercooked poultry meat, contaminated from intestinal contents during processing. In broilers, Campylobacter can grow to very high densities in the caeca, and is often considered to be a commensal or an opportunistic pathogen in poultry. Reduction of caecal loads of Campylobacter may assist in lowering incidence rates of Campylobacter food poisoning. To achieve this, there needs to be a better understanding of the dynamics of Campylobacter colonisation in its natural niche, and the effect of the local microbiome on colonisation. Previous studies have shown that the microbiome differed between Campylobacter colonised and non?colonised chicken intestinal samples. To characterise the microbiome of Campylobacter-colonised broilers, caecal samples of 100 randomly selected birds from four farms were analysed using amplified 16S rRNA gene sequences. Bacterial taxonomic analysis indicated that inter-farm variation was greater than intra-farm variation. The two most common bacterial groups were Bacteroidetes and Firmicutes which were present in all samples and constituted 29.7 ? 63.5% and 30.2 ? 59.8% of the bacteria present, respectively. Campylobacter was cultured from all samples, ranging from 2 to 9 log10 CFU g-1. There was no clear link between Campylobacter counts and Firmicutes, Bacteroidetes or Tenericutes levels in the 16S rRNA Operational Taxonomic Unit (OTU)-based analysis of the caecal microbiome, but samples with high Campylobacter counts (> 9 log CFU g-1) contained increased levels of Enterobacteriaceae. A decrease in Lactobacillus abundance in chicken caeca was also associated with high Campylobacter loads. The reported associations with Lactobacillus and Enterobacteriaceae match changes in the intestinal microbiome of chickens and mice previously reported for Campylobacter infection, and raises the question about temporality and causation; as to whether increases in Campylobacter loads create conditions adverse to Lactobacilli and/or beneficial to Enterobacteriaceae, or that changes in Lactobacilli and Enterobacteriaceae levels created conditions beneficial for Campylobacter colonisation. If these changes can be controlled, this may open opportunities for modulation of chicken microbiota to reduce Campylobacter levels for improved food safety.
Bovine tuberculosis (bTB) caused by Mycobacterium bovis is the most serious endemic disease affecting livestock in the UK. The European badger (Meles meles) is the most important wildlife reservoir of bTB transmission to cattle, making eradication particularly difficult. In this respect, oral vaccination with the attenuated M. bovis vaccine Bacillus Calmette-Guerin (BCG) has been suggested as a wide-scale intervention to reduce bTB infection in badgers. However, experimental studies show variable protection. Among the possibilities for this variation is that the resident gut bacteria may influence the success of oral vaccination in badgers; either through competitive exclusion and/or inhibition, or via effects on the host immune system. In order to explore this possibility, we have tested whether typical gut commensals such as Lactic Acid Bacteria (LAB) have the capacity to impact on the viability and survival rate of BCG and to modulate the immune response to BCG using an in vitromodel.
Twelve LAB isolated from badger faeces displayed inhibitory activity to BCG that was species-dependent. Weissella had a bacteriostatic effect, whereas isolates of enterococci, lactobacilli and pediococci had a more bactericidal activity. Furthermore, BCG-induced activation of the pro-inflammatory transcription factor NF-ºB in human THP-1 macrophages was modulated by LAB in a strain-dependent manner. Most pediococci enhanced NF-ºB activation but one strain had the opposite effect. Interestingly, isolates of enterococci, lactobacilli and weissella had different effects as immunomodulators of BCG-induced macrophage responses as some had no significant influence on NF-ºB activation, but others increased it significantly.
Our in vitro results show that LAB isolated from badgers exhibit significant inhibitory activity against BCG and influence the immune activation mediated by BCG in a human macrophage assay. These findings suggest that gut commensal bacteria could play a role in influencing the outcome of oral BCG vaccination. Inactivated cells of LAB, or LAB that are bacteriostatic but have a synergistic immunostimulatory effect with BCG, could be potential adjuvants to be used for oral vaccination in badgers. Further work is needed to take into account the complex nature of the gut microbiome, specific immunity of the badger and the in vivo context.
Background: Many investigations into the determinants of hand hygiene (HH) behaviour have explored only individual predictors or were designed according to arguably overly simplistic models of behaviour. Consequently, important influences on HH behaviour, including habit and emotion, are sometimes neglected. This study is the first to employ the Theory of Interpersonal Behaviour as a comprehensive model for understanding the determinants of HH behaviour. Method: A self-report questionnaire was conducted with staff from two large UK veterinary referral practices. Participants (n = 75) reported their HH behaviour and responded to statements rating the importance of social norms, self-protection, patient protection, time pressures, access to equipment, habit and disgust, to their HH behaviour. Results: Regression analysis showed that, overall, determinants explained 46% of variance (p < .001) in self-reported HH behaviour, with time constraints being the strongest predictor (² = ?.47, p < .001) followed by difficulty finding equipment (² = ?.21, p = .05). Discussion: Time constraints may be the most important influence on HH adherence among the determinants investigated. Future researchers should consider employing theoretical models to aid a more comprehensive understanding of the psychology underlying HH adherence and HH interventions.
The aim of this study was to determine the reliability of lactic acid bacteria (LAB) as heterologous hosts for the expression of MPB70 and MPB83, two Mycobacterium bovis antigens that possess diagnostics and immunogenic properties, respectively. We therefore generated recombinant cells of Lactococcus lactis and Lactobacillus plantarum that carried hybrid genes encoding MPB70 and MPB83 fused to signal peptides that are specifically recognized by LAB. Only L. lactis was able to secrete MPB70 using the L. lactis signal peptide Usp45, and to produce MPB83 as an immunogenic membrane protein following its expression with the signal peptide of the L. plantarum lipoprotein prsA. Inactivated cells of MPB83-expressing L. lactis cultures enhanced NF-ºB activation in macrophages. Our results show that L. lactis is a reliable host for the secretion and functional expression of antigens that are naturally produced by M. bovis, the causative agent of bovine tuberculosis (bTB). This represents the first step on a long process to establishing whether recombinant LAB could serve as a food-grade platform for potential diagnostic tools and/or vaccine interventions for use against bTB, a chronic disease that primarily affects cattle but also humans and a wide range of domestic and wild animals.
Sexually transmitted diseases (STDs) can be important drivers of population dynamics because of their negative effects on reproduction. However, screening for STDs, especially in wildlife populations, is widely neglected. Using the promiscuous, polygynandrous European badger (Meles meles) as a model, we investigated the presence and prevalence of herpesviruses (HVs) in a wild, high-density population and assessed potential differences in somatic fitness and female reproductive condition between infected and uninfected individuals. We collected n=98 genital swabs from 71 females (51 adults and 20 cubs) and 27 males (26 adults and 1 cub) during spring and summer 2015. Using a PCR specific for a mustelid ±-HV, all genital-swab samples tested negative. In a panherpes PCR, a ³-HV was found in 55% (54/98; 39 adults and 15 cubs), identified as mustelid gammaherpesvirus 1 (MusGHV-1) using DNA sequencing. This contrasts with the results of a previous study, which reported MusGHV-1 in 98% (354/361) of blood samples taken from 218 badgers in the same population using PCR. The detection of MusHV-1 in the female reproductive tract strongly indicates the potential for a horizontal and, likely also a vertical, route of transmission. Our results suggest a potential linkage of genital HVs and impaired future reproductive success in females, but because reproductive failure can have many reasons in badgers, the causative link of this negative relationship remains to be investigated.
The deployment of baits containing vaccines or toxins has been used successfully in the management of wildlife populations, including for disease control. Optimisation of deployment strategies seeks to maximise uptake by the targeted population whilst ensuring cost effectiveness. Tuberculosis (TB) caused by infection with Mycobacterium bovis affects a broad range of mammalian hosts across the globe, including cattle, wildlife and humans. The control of TB in cattle in the UK and Republic of Ireland is hampered by persistent infection in European badgers (Meles meles). The present study aimed to determine the best strategy for maximising uptake of an oral vaccine by wild badgers, using a surrogate novel bait deployed at 40 badger social groups. Baits contained a blood-borne biomarker (Iophenoxic Acid, IPA) in order to measure consumption in badgers subsequently cage trapped at targeted setts. Evidence for the consumption of bait was found in 83% (199/240) of captured badgers. The probability that badgers had consumed at least one bait (IPA >10 ¼g ml-1) was significantly higher following deployment in spring than in summer. Lower uptake amongst social groups where more badgers were captured, suggested competition for baits. The probability of bait consumption was significantly higher at groups where main and outlier setts were provided with baits than at those where outliers were present but not baited. Badgers captured 10?14 days post bait feeding had significantly higher levels of bait uptake compared to those caught 24?28 days later. Uptake rates did not vary significantly in relation to badger age and whether bait was placed above ground or down setts. This study suggests that high levels of bait uptake can be achieved in wild badger populations and identifies factors influencing the potential success of different deployment strategies. The implications for the development of an oral badger vaccine are discussed.
The control of tuberculosis (TB) in cattle in the UK and Ireland is compromised by transmission of Mycobacterium bovis to cattle from the European badger (Meles meles), which acts as a wildlife reservoir. Vaccination of badgers could potentially contribute to TB control but the only licensed vaccine is injectable BadgerBCG which requires the live-capture of badgers. Current research is aimed at developing an oral TB vaccine (where vaccine is contained within bait) that is intended to be more cost-effective to deploy over large areas. In order to identify a lead product, candidate baits identified from captive badger studies were evaluated in three successive bait screening studies with wild badgers. A fourth field study, using the lead candidate bait and biomarkers, investigated the effectiveness of different carriers for their potential to deliver liquid payloads (vaccine surrogate). In each field study, bait disappearance was monitored daily for ten days and remote video surveillance was used to determine preference (i.e. the order in which baits were taken). In the carrier study, biomarkers were used to determine what proportion of subsequently trapped badgers had ingested the bait and the vaccine-carrier biomarker payload. Across all four studies, 79% (3397/4330) of baits were taken by badgers although the number varied significantly by badger social group and bait type. In all studies, bait disappearance increased over time, with 75?100% of baits being taken by day ten. In the carrier study, 75% (9/12) of trapped badgers tested positive for at least one of the biomarkers and the type of carrier did not influence bait attractiveness. Together with data from complementary laboratory and captive animal studies, this study identified a highly attractive and palatable bait (peanut-based paste bait; PT) and vaccine-carrier (hydrogenated peanut oil; HPO) combination with the potential to deliver a liquid vaccine to wild badgers.
In developing an oral bait BCG vaccine against tuberculosis in badgers we wanted to understand the conditions of the gastrointestinal tract and their impact on vaccine viability. Conditions mimicking stomach and small-intestine caused substantial reduction in BCG viability. We performed in vivo experiments using a telemetric pH monitoring system and used the data to parameterise a dynamic in vitro system (TIM-1) of the stomach and small intestine. Some BCG died in the stomach compartment and through the duodenum and jejunum compartments. BCG survival in the stomach was greatest when bait was absent but by the time BCG reached the jejunum, BCG viability was not significantly affected by the presence of bait. Our data suggest that from a starting quantity of 2.85 ± 0.45 x 108 colony-forming units of BCG around 2 log10 may be killed before delivery to the intestinal lymphoid tissue. There are economic arguments for reducing the dose of BCG to vaccinate badgers orally. Our findings imply this could be achieved if we can protect BCG from the harsh environment of the stomach and duodenum. TIM-1 is a valuable, non-animal model with which to evaluate and optimise formulations to maximise BCG survival in the gastrointestinal tract.
Alveolar type II (ATII) cells play a key role as part of the distal lung epithelium, including roles in the innate immune response and as self-renewing progenitors to replace alveolar type I (ATI) cells during regeneration of the alveolar epithelium. Their secretion of surfactant protein helps to maintain homeostasis in the distal lung and exert protective, antimicrobial properties. Despite the cell?s crucial roles, they remain difficult to study, in part due to inefficient and expensive isolation methods, a propensity to differentiate into alveolar type I cells in culture and susceptibility to fibroblast overgrowth from primary isolations. Published methods of isolation often require specialist technology, negatively impacting the development of in vitro models of disease, including bovine tuberculosis (BTB), a serious re-emerging disease in both animals and humans worldwide. We present here a simple and cost effective method that may be utilised in the generation of bovine primary ATII cells. These exhibit an ATII phenotype in 2D and 3D culture in our studies and are conducive to further study of the role of ATII cells in bovine respiratory diseases.
Alveolar type II (ATII) cells play a key role as part of the distal lung epithelium, including in the innate immune response and as self?renewing progenitors to replace alveolar type I (ATI) cells during epithelial regeneration. Their secretion of surfactant protein helps maintain homeostasis and exerts protective, antimicrobial properties. ATII cells remain difficult to study, partly due to inefficient and expensive isolation methods, a propensity to differentiate into ATI cells, and susceptibility to fibroblast contamination. Published methods of isolation often require specialized technology, negatively impacting the development of in vitro models of disease, including bovine tuberculosis. Presented here is a simple and cost?effective method for generation of bovine primary ATII cells. These cells exhibit an ATII phenotype in 2D and 3D culture and are conducive to further study of the role of ATII cells in bovine respiratory diseases.
Bacillus Calmette?Guérin (BCG) vaccine is the only licensed vaccine against tuberculosis (TB) in humans and animals. It is most commonly administered parenterally, but oral delivery is highly advantageous for the immunisation of cattle and wildlife hosts of TB in particular. Since BCG is susceptible to inactivation in the gut, vaccine formulations were prepared from suspensions of Eudragit L100 copolymer powder and BCG in phosphate-buffered saline (PBS), containing Tween® 80, with and without the addition of mannitol or trehalose. Samples were frozen at -20 °C, freeze-dried and the lyophilised powders were compressed to produce BCG?Eudragit matrices. Production of the dried powders resulted in a reduction in BCG viability. Substantial losses in viability occurred at the initial formulation stage and at the stage of powder compaction. Data indicated that the Eudragit matrix protected BCG against simulated gastric fluid (SGF). The matrices remained intact in SGF and dissolved completely in simulated intestinal fluid (SIF) within three hours. The inclusion of mannitol or trehalose in the matrix provided additional protection to BCG during freeze-drying. Control needs to be exercised over BCG aggregation, freeze-drying and powder compaction conditions to minimise physical damage of the bacterial cell wall and maximise the viability of oral BCG vaccines prepared by dry powder compaction.
Bovine tuberculosis (TB) continues to be an intractable problem in many countries, particularly where ?test and slaughter? policies cannot be implemented or where wildlife reservoirs of Mycobacterium bovis infection serve as a recurrent source of infection for domestic livestock. Alternative control measures are urgently required and vaccination is a promising option. Although the M. bovis bacille Calmette-Guérin (BCG) vaccine has been used in humans for nearly a century, its use in animals has been limited, principally as protection against TB has been incomplete and vaccination may result in animals reacting in the tuberculin skin test. Valuable insights have been gained over the past 25 years to optimise protection induced by BCG vaccine in animals and in the development of tests to differentiate infected from vaccinated animals (DIVA). This review examines factors affecting the efficacy of BCG vaccine in cattle, recent field trials, use of DIVA tests and the effectiveness of BCG vaccine in other domestic livestock as well as in wildlife. Oral delivery of BCG vaccine to wildlife reservoirs of infection such as European badgers, brushtail possums, wild boar, and deer has been shown to induce protection against TB and could prove to be a practical means to vaccinate these species at scale. Testing of BCG vaccine in a wide range of animal species has indicated that it is safe and vaccination has the potential to be a valuable tool to assist in the control of TB in both domestic livestock and wildlife.
European badgers are a wildlife reservoir of bovine tuberculosis in parts of Great Britain. Accurate diagnosis of tuberculosis in badgers is important for the development of strategies for the control of the disease. Sensitive serological tests for badger TB are needed for reasons such as cost and simplicity. Assay of mucosal IgA could be useful for diagnosing respiratory pathogens such as Mycobacterium bovis and for monitoring the response to mucosal vaccination. To develop an IgA assay, we purified secretory IgA from badger bile, identifying secretory component (SC), heavy chain (HC) and light chain (LC), at 66, 46 and 27 Kda, respectively, on the basis of size comparison with other species. Monoclonal antibodies (mAbs) were generated to purified IgA.We selected two for ELISA development. The detection limit of the IgA-specific mAbs was found to be approximately 20 ng/mL when titrated against purified badger bile. One monoclonal antibody specific for badger IgA was used to detect IgA in serum and tracheal aspirate with specificity to an immunodominant antigen of M. bovis. An M. bovis infection dose-dependent IgA response was observed in experimentally infected badgers. IgA was also detected by immunohistochemistry in the lungs of bTB-infected badgers. With further characterisation, these represent new reagents for the study of the IgA response in badgers.
Mycobacterium bovis is the causative agent of bovine tuberculosis and the predominant cause of zoonotic tuberculosis in people. Bovine tuberculosis occurs in farmed cattle but also in a variety of wild animals, which form a reservoir of infection. Although direct transmission of tuberculosis occurs between mammals, the low frequency of contact between different host species and abundant shedding of bacilli by infected animals suggests an infectious route via environmental contamination. Other intracellular pathogens that transmit via the environment deploy strategies to survive or exploit predation by environmental amoebae. To explore if M. bovis has this capability, we investigated its interactions with the soil and dung-dwelling amoeba, Dictyostelium discoideum. We demonstrated that M. bovis evades phagocytosis and destruction by D. discoideum and actively transits through the amoeba using the ESX-1 Type VII Secretion System as part of a programme of mechanisms, many of which have been co-opted as virulence factors in the mammalian host. This capacity of M. bovis to utilise an environmental stage between mammalian hosts may enhance its transmissibility. In addition, our data provide molecular evidence to support an evolutionary role for amoebae as training grounds for the pathogenic M. tuberculosis complex.
Probiotics represent a non-invasive, environmentally-friendly alternative to reduce infectious diseases in wildlife species. Our aim was to evaluate the potential of typical gut commensals, such as lactic acid bacteria (LAB), as wildlife probiotics. The selected LAB were isolated from European badgers (Meles meles); a wildlife reservoir of bovine tuberculosis, and comprised four different genera: Enterococcus; Weissella; Pediococcus; and Lactobacillus. The enterococci displayed a phenotype and genotype that correlate with the production of antibacterial peptides and stimulation of antiviral responses. However, these isolates carry virulence and antibiotic resistance genes. Weissella showed some anti-mycobacterial activity due to their ability to produce lactate and ethanol. Interestingly, lactobacilli and pediococci modulated pro-inflammatory phagocytic responses that associate with protection against pathogens; and these responses agreed with the presence of immunomodulatory markers in their genomes. Although both lactobacilli and pediococci showed tolerance to antibiotics, this resistance was naturally acquired and almost all isolates possessed a strong phylogenetic relationship with isolates from food and healthy animals. Our results show that LAB display probiotic benefits that depend on the genera. Lactobacilli and pediococci are probably the most interesting candidates as probiotics against infectious diseases in wildlife because of their food-grade status and ability to modulate protective innate immune responses.
Macdonald Alistair, Chambers Mark, La Ragione Roberto, Wyles Kayleigh, Poyade Matthieu, Wales Andrew, Klepacz Naomi, Kupfer Tom, Watson Fraje, Noble Shona Using novel visualisation methods to combat infection risk during clinical practices.,Proceedings of the 6th International Conference on Design4Health
Lesellier Sandrine, Birch Colin P. D., Davé Dipesh, Dalley Deanna, Gowtage Sonya, Palmer Simonette, McKenna Claire, Williams Gareth A., Ashford Roland, Weyer Ute, Beatham Sarah, Coats Julia, Nunez Alex, Sanchez-Cordon Pedro, Spiropoulos John, Powell Stephen, Sawyer Jason, Pascoe Jordan, Hendon-Dunn Charlotte, Bacon Joanna, Chambers Mark A. (2020) Bioreactor-Grown Bacillus of Calmette and Guérin (BCG) Vaccine Protects Badgers against Virulent Mycobacterium bovis When Administered Orally: Identifying Limitations in Baited Vaccine Delivery,Pharmaceutics 12 (8)
Bovine tuberculosis (TB) in Great Britain adversely affects animal health and welfare and is a cause of considerable economic loss. The situation is exacerbated by European badgers (Meles meles) acting as a wildlife source of recurrent Mycobacterium bovis infection to cattle. Vaccination of badgers against TB is a possible means to reduce and control bovine TB. The delivery of vaccine in oral bait holds the best prospect for vaccinating badgers over a wide geographical area. There are practical limitations over the volume and concentration of Bacillus of Calmette and Guérin (BCG) that can be prepared for inclusion in bait. The production of BCG in a bioreactor may overcome these issues. We evaluated the efficacy of oral, bioreactor-grown BCG against experimental TB in badgers. We demonstrated repeatable protection through the direct administration of at least 2.0 × 108 colony forming units of BCG to the oral cavity, whereas vaccination via voluntary consumption of bait containing the same preparation of BCG did not result in demonstrable protection at the group-level, although a minority of badgers consuming bait showed immunological responses and protection after challenge equivalent to badgers receiving oral vaccine by direct administration. The need to deliver oral BCG in the context of a palatable and environmentally robust bait appears to introduce such variation in BCG delivery to sites of immune induction in the badger as to render experimental studies variable and inconsistent.
An oral vaccine is a potential tool to tackle the reservoir of Mycobacterium bovis in European badgers (Meles meles), which contributes to tuberculosis of cattle in the British Isles. Inferences about vaccine protection against experimental challenge with M. bovis depend on the measurement of tuberculosis. Assessment of tuberculosis in larger species, such as badgers, is typically based on the tuberculous lesions visible at post-mortem examination and histopathology. We have developed a robust scoring system for tuberculous lesions by combining several parallel measures, which we call the ?disease burden score? (DBS).
Alternative scoring systems were compared within a regression analysis applied to observations from a total of 168 badgers from eight studies, including 107 badgers subjected to vaccination treatment and 61 non-vaccinated controls. The analysis included incidental observations that were recorded from each badger as potential covariate factors explaining some of the variation among animals sourced from the wild.
DBS was found to be the most accurate and reliable of the scoring systems compared. By taking account of significant covariates affecting disease, application of the DBS reduced residual variance by 22.9%. A previously used measure, based on assessment of visible lesions, was suboptimal due to non-uniform variance that increased with expected value, although square root transformation addressed this issue. The covariate model fitted to DBS included sex (males had higher DBS), weight (negatively associated with DBS) and immunological evidence of prior exposure to Mycobacterium avium (positively associated with DBS).
We identified improved measures of tuberculous disease derived from data already collected. We also demonstrated that the proper scaling of measurements of disease in such models is necessary and can be determined empirically. The covariates which were most strongly associated with the severity of disease are important in experimental studies involving outbred animals with variable background.
Ashford Roland T., Anderson Paul, Waring Laura, Dave Dipesh, Smith Freya, Delahay Richard J., Gormley Eamonn, Chambers Mark A., Sawyer Jason, Lesellier Sandrine (2020) Evaluation of the Dual Path Platform (DPP) VetTB assay for the detection of Mycobacterium bovis infection in badgers,PREVENTIVE VETERINARY MEDICINE 180 105005
ELSEVIER SCIENCE BV
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, represents a major animal health issue. In the United Kingdom and the Republic of Ireland, European badgers (Meles meles) have been shown to act as a reservoir of M. bovis infection, hindering the eradication of bTB in livestock. The availability of suitable diagnostic assays, particularly those that may be applied in a ?trap-side? setting, would facilitate the implementation of a wider range of disease control strategies. Here we evaluate the Dual Path Platform (DPP) VetTB assay, a lateral-flow type test for detecting antibodies to M. bovis antigens (MPB83 and ESAT-6/CFP-10). Both serum and whole blood were evaluated as diagnostic samples. Additionally, two methods were evaluated for interpretation of test results (qualitative interpretation by eye and quantitative measurement using an optical reader). The antibody response to MPB83 detected by the DPP VetTB assay increased significantly following experimental M. bovis infection of badgers, whilst the response to ESAT-6/CFP-10 showed no significant change. In sera from TB-free captive and naturally M. bovis infected wild badgers the MPB83 response exhibited a sensitivity of 55 % by eye and quantitative reader (95 % CI: 40?71 and 38?71, respectively), with slightly lower specificity when read by eye (93 % compared to 98 %; 95 % CI: 85?100 and 90?100, respectively). In whole blood, the DPP VetTB assay MPB83 response exhibited a sensitivity of 65 % (95 % CI: 50?80) when interpreted by eye and 53 % (95 % CI: 36?69) using quantitative values, whilst the specificity was 94 % and 98 % respectively (95 % CI: 88?100 and 90?100). Comparison with contemporaneous diagnostic test results from putatively naturally infected and TB-free badgers demonstrated varying levels of agreement. Using sera from naturally M. bovis infected and TB-free badgers, with post mortem confirmation of disease status, the DPP VetTB assay exhibited a sensitivity of 60 % (95 % CI: 41?77) when interpreted using quantitative values (specificity 95 %; 95 % CI: 76?100), and 67 % (95 % CI: 50?84) when read by eye (specificity 95 %; 95 % CI: 86?100). Further work is required to robustly characterize the DPP VetTB assay?s performance in a wider selection of samples, and in the practical and epidemiological contexts in which it may be applied.
Mycobacterium bovis Bacillus Calmette?Guérin (M. bovis BCG) was generated over a century ago for protection against Mycobacterium tuberculosis (Mtb) and is one the oldest vaccines still in use. The BCG vaccine is currently produced using a pellicle growth method, which is a complex and lengthy process that has been challenging to standardise. Fermentation for BCG vaccine production would reduce the complexity associated with pellicle growth and increase batch to batch reproducibility. This more standardised growth lends itself to quantification of the total number of bacilli in the BCG vaccine by alternative approaches, such as flow cytometry, which can also provide information about the metabolic status of the bacterial population. The aim of the work reported here was to determine which batch fermentation conditions and storage conditions give the most favourable outcomes in terms of the yield and stability of live M. bovis BCG Danish bacilli. We compared different media and assessed growth over time in culture, using total viable counts, total bacterial counts, and turbidity throughout culture. We applied fluorescent viability dyes and flow cytometry to measure real-time within-culture viability. Culture samples were stored in different cryoprotectants at different temperatures to assess the effect of these combined conditions on bacterial titres. Roisin?s minimal medium and Middlebrook 7H9 medium gave comparable, high titres in fermenters. Flow cytometry proved to be a useful tool for enumeration of total bacterial counts and in the assessment of within-culture cell viability and cell death. Of the cryoprotectants evaluated, 5% (v/v) DMSO showed the most significant positive effect on survival and reduced the negative effects of low temperature storage on M. bovis BCG Danish viability. In conclusion, we have shown a reproducible, more standardised approach for the production, evaluation, and storage of high titre, viable, BCG vaccine.