Vaccine potential of HLA A2 epitopes from Leishmania Cysteine Protease Type III (CPC)

Although the precise host-defence mechanisms are not completely understood, T-cell-mediated immune responses are believed to play a pivotal role in controlling parasite infection. In this study, the potential HLA*A2 restricted peptides were predicted and the ability of peptides to bind HLA-A*02 was confirmed by a MHC stabilization assay. Two of the peptides tested stabilized HLA-A*02: (a)LLATTVSGL(P1) and(b)LMTNGPLEV(P3). The potential of the peptides to generate protective immune response was evaluated in treated visceral leishmaniasis patients as well as in healthy control subjects. Our data suggest that CD8+ T cell proliferation against the selected peptide was significantly higher compared to unstimulated culture conditions. The stimulation of peripheral blood mononuclear cells with epitopes individually or as a cocktail upregulated IFN-γ production, which indicates its pivotal role in protective immune response. The IFN-γ production was mainly in a CD8+ T cells dependent manner, which suggested that these epitopes had an immunoprophylactic potential in a MHC class I dependent manner. Moreover, no role of the CD3+T cell was observed in the IL-10 production against the selected peptides, and no role was found in disease pathogenesis. Further studies on the role of these synthetic peptides may contribute significantly to developing a polytope vaccine idea towards leishmaniasis. This article is protected by copyright. All rights reserved.