Safety and skin delayed-type hypersensitivity response in vervet monkeys immunized with Leishmania donovani sonicate antigen delivered with adjuvants

in this study, we report on the safety and skin delayed-type hypersensitivity (dth), responses of the leishmania donovani whole cell sonicate antigen delivered in conjunction with alum-bcg (albcg), montanide isa 720 (misa) or monophosphoryl lipid a (mpla) in groups of vervet monkeys. following three intradermal injections of the inoculums on days 0, 28 and 42, safety and dth responses were assessed. preliminary tumor necrosis factor alpha (tnf-α) and interferon gamma (ifn-γ) levels were also measured and these were compared with dth. only those animals immunized with alum-bcg reacted adversely to the inoculum by producing ulcerative erythematous skin indurations. non-parametric analysis of variance followed by a post-test showed significantly higher dth responses in the misa+ag group compared with other immunized groups (p < 0.001). the mpla+ag group indicated significantly lower dth responses to the sonicate antigen compared with the albcg+ag group. there was a significant correlation between the dth and cytokine responses (p < 0.0001). based on this study we conclude that leishmania donovani sonicate antigen containing misa 720 is safe and is associated with a strong dth reaction following immunization.