Anti-leishmanial Vaccination with Parasite Antigens in Liposomes Relies on the Effective Induction of T cell Responses and Inhibits Parasite Metastasis in Mice

Lezama Dávila CM and Isaac-Márquez AP

In this work we vaccinated CBA/ca and C57BL/10 mice presenting different clinical forms of Leishmaniasis after infection with L. mexicana parasites. CBA/ca mice develop localized cutaneous Leishmaniasis while C57BL/10 mice develop disseminated cutaneous Leishmaniasis 14 weeks postinfection. We used an electrophoretic procedure to record parasite molecules present in our vaccine preparation. Vaccination was effective to prevent disease development in CBA/ca but not C57BL/10 animals. There were not differences in the number of T cell subsets among normal and vaccinated animals of either strain as determined by flow cytometry. DTH response and serum INF-gamma [IFN] levels were induced in vaccinated CBA/ca but C57BL/10 animals. Vaccine induced protection was adoptively transferred by CD4+ and CD8+ T cells into CBA/ca [not in C57BL/10 mice] naïve syngeneic recipient mice challenged with virulent parasites. We concluded that effective protection through vaccination of CBA/ca but not C57BL/10 mice correlates with the induction of protective CD4+ and CD8+ T cells, specific DTH response and production of IFN while the synthesis of specific IgG anti-Leishmania is induced in both strains of vaccinated animals and vaccination prevents parasite metastasis to different skin locations in C57BL/10 mice.