Leishmania donovani whole cell antigen delivered with adjuvants protects against visceral leishmaniasis in vervet monkeys(Chlorocebus aethiops)

In a previous immunogenicity and efficacy study in mice,montanide ISA 720(MISA)was indicated to be a better adjuvant than bacillus calmette guerin vaccine(BCG)for a Leishmania vaccine.In the present study,we report the safety,immunogenicity and efficacy of Leishmania donovani(L.donovani)sonicated antigen delivered with alum-BCG(AlBCG),MISA or monophosphoryl lipid A(MPLA)in vervet monkeys following intradermal inoculums.Vaccinated and control animals were challenged with virulent L.donovani parasites and the parasitic burden was determined.Only animals vaccinated with alum-BCG adversely reacted to the inoculum by producing ulcerative erythematous skin indurations.Non-parametric ANOVA followed by a post test showed significantly higher IgG antibodies,and revealed the presence of lymphoproliferative and interferon gamma responses in both AlBCG+Ag and MISA+Ag as compared to the MPLA+Ag or other groups(P < 0.001).We conclude that L.donovani sonicated antigen containing MISA is safe and is associated with protective immune response against Leishmania donovani infection in the vervet monkey model.