Immuno stimulating glycophosphosphingolipid antigen from Leishmania donovani is recognized by visceral leishmaniasis patient sera

Surface antigens on Leishmania promastigotes and infected macrophages are obvious targets in immunoprophylaxis for leishmanial infection. The glycophosphosphingolipid (GSPL) antigen isolated from Leishmania donovani surface membrane was recognized by sera from patients with visceral leishmaniasis. GSPL was also expressed on the membrane of parasite-infected macrophages. The effect of GSPL on the production of reactive oxygen species (ROS) and reactive nitrogen intermediates (RNI) was studied using the macrophage cell line J774.1. In addition, induction of IFNγ, IL4, IL10, IL12 secretion in presence of GSPL was investigated in PBMC from normal individuals. ROS and RNI in addition to IFNγ and IL12 were induced by GSPL. Though there was a moderate induction of IL10, there was very little induction of the Th2 cytokine IL4. GSPL also induced blood cells to proliferate. The data suggests that this functionally important antigen of L. donovani may be used as a candidate vaccine.