Epitope mapping and protective immunity elicited by adenovirus expressing theLeishmaniaamastigote specific A2 antigen: Correlation with IFN-[gamma] and cytolytic activity by CD8+ T cells

A2 was identified as an amastigote virulence factor ofLeishmania(Leishmania)donovaniand as a candidate antigen for vaccine development against visceral leishmaniasis. Here, predicted hydrophilic, class I and II MHC-binding synthetic peptides were used to define epitopes recognized by A2-specific antibodies, CD8+ T and CD4+ T cells, respectively. Immunization of BALB/c mice with adenovirus expressing A2 (AdA2) resulted in low antibody response, contrasting with high levels of IFN-γ producing CD4+ T and CD8+ T cells specific for A2. Further, A2-specific CD8+ T cells from immunized mice were capable of lysing sensitized target cellsin vivo. Finally, we demonstrated an association of A2-specific T cell responses and reduced parasitism in both liver and spleen from mice immunized with AdA2 and challenged withL.(L.)chagasi.