The adjuvant effects of IL-12 and BCG on autoclaved Leishmania major vaccine in experimental cutaneous leishmaniasis.

Cutaneous leishmaniasis is a universal disease causing skin ulceration and deformity. A reliable vaccine remains to be a possible practical means of control. The amastigotes multiply intracellulary in macrophages provoking a cell-mediated type of immune response. IL-12 is the central cytokine of CMI. It is produced by sensitized macrophages, stimulates both Th1 and NK cells to secrete IFN-gamma which in turn activates the intracellular killing of Leishmania in macrophages via increased oxygen radicals. This work aimed mainly at studying the adjuvant effect of IL-12 on autoclaved L. major (ALM) vaccine, compared to that of BCG in L. major infection. The material included five groups of Swiss albino mice; the test group infected after receiving ALM+IL-12, a non-infected control group, and three other control groups infected after receiving ALM+BCG, IL-12 alone and BCG alone L. major was cultured to provide promastigotes for vaccine and infection. The measured parameters included the lesion size, type and progress; the parasite density and the level of IFN-gamma in serum. The results showed that the best protection against challenge infection was obtained by ALM + IL-12 followed by ALM + BCG. The former is recommended for use as a vaccine with regards to its proved efficacy and known safety.