Induction of delayed-type hypersensitivity by ICRC anti-leprosy vaccine and the adoptive transfer of cell-mediated immunity in mice.

The immunogenic potency of anti-leprosy ICRC vaccine preparations was determined by foot pad enlargement in mice. Female Balb/c mice were sensitized by I.D. route with irradiated, heat-killed or live antigens of 2 strains (C-44 and C-75) of ICRC bacilli and tested against lepromin and ICRC-antigens. ICRC antigens sensitized mice against lepromin; similarly, BCG and M. leprae sensitized mice, which showed good cross reactivity with ICRC antigens. A mixture of irradiated ICRC bacilli and live BCG was not more immunogenic to mice than its single constituents. The immunity induced by ICRC antigens could be adoptively transferred to syngeneic recipients by sensitized spleen cells.