Immunostimulant activity of a novel lipopeptide and its protective action against Leishmania donovani.

Novel lipopeptides 84/201 and 86/450 synthesized in this laboratory stimulated antibody and delayed type hypersensitivity (DTH) response to ovalbumin in guinea pigs. Lipopeptide 86/450 also stimulated antibody and DTH responses in albino mice and enhanced nonspecifically macrophage migration index (MMI), phagocytic activity and incorporation of [14C] glucosamine in peritoneal macrophages of the treated animals. Proliferative response of splenocytes from lipopeptide 86/450 treated animals was significantly higher than that from untreated controls. Peritoneal macrophages from lipopeptide 86/450 treated mice were less susceptible to Leishmania donovani promastigote invasion when co-cultured in vitro. The treated animals on challenge with L. donovani promastigote/amastigote showed 80 to 90% lower intake of infection than the control animals.