BCG vaccination to Mycobacterium leprae infection in mice

BCG vaccine (Tokyo strain) was given in BALB/cA mice intradermally 1 or 3 months before Mycobacterium leprae (M. leprae) challenge as modified Shepard's method. The vaccine dosage was 10^7-8 or 10⁶. The BCG gave good protection in both dosages and both challenges against M. leprae infection. Lymphocytes proliferations of BCG-vaccinated splenocyte cultures in response to M. leprae lysate or BCG components (hsp65, 38kD, 30kD or 12kD protein) were tested, and potent proliferative responses were seen in the cultures with M. leprae lysate and hsp65. Furthermore, γ-IFN productions were positive in the cultures with M. leprae lysate or hsp65, but negative with other antigens. The production of γ-IFN with hsp65 was never inhibited with polymyxin B, but inhibited with IL 10. These results show that BCG (Tokyo strain) is a useful vaccine for M. leprae infection in mice, and one of the compounds of BCG, hsp65, may be a effective antigen component for protection of M. leprae infection inducing Th1 type cytokine.