Immunological responses of Eurasian badgers (Meles meles) vaccinated with Mycobacterium bovis BCG (bacillus calmette guerin)

Wildlife species, such as the badger (Meles meles), may act as maintenance hosts for Mycobacterium bovis and contribute to the spread and persistence of tuberculosis in associated cattle populations. Targeted vaccination of b adgers against tuberculosis is an option that, if successfully employed, co uld directly facilitate the advancement of bovine tuberculosis eradication in affected areas. In this study, the immunological responses of a group of badgers vaccinated subcutaneously with low doses of Mycobacterium bovis ba cillus calmette guerin (BCG) were measured in vitro and compared with non-v accinated control animals over a period of 42 weeks. Peripheral blood monon uclear cells (PBMC) from badgers which had received repeated booster inject ions of BCG proliferated in response to culture with PPD-bovine (purified p rotein derivative of tuberculin). The proliferation was significantly great er than that seen in the non-vaccinated control group. In contrast, the pro liferative response of PBMC from vaccinated badgers to PPD-avian declined r elative to the control group. These results demonstrate that repeated vacci nation of badgers with M. bovis BCG induced a population of T-lymphocytes r esponsive to specific antigens in PPD-bovine. Throughout the course of the study, the sera from all animals were tested (BrockTest) by an enzyme-linke d immunosorbent assay (ELISA) system for the presence of antibodies to MPB8 3, a serodominant antigen whose expression is high in M. bovis, but very lo w in BCG (Pasteur). No animals at any stage showed seroconversion to the an tigen, consistent with the tuberculosis-free status of the badgers under st udy. (C) 2001 Elsevier Science B.V. All rights reserved.