Leishmania donovani flagellum-specific epitopes mediating host-parasite interactions.

Monoclonal antibodies were developed against flagellar components of promastigotes of Leishmania donovani. The monoclonal antibody produced by clone A11 (mAb A11) recognised epitopes in the polypeptides with molecular weights of 86, 66 and weakly 53 kDa. These epitopes were found to be distributed along the flagellum and at the anterior end of promastigotes. The mAb A11 of IgG1 isotype strongly agglutinated the promastigotes of L. donovani. The prior treatment of promastigotes of L. donovani with mAb A11 resulted in a significant (P < 0.001) reduction in the attachment of promastigotes to cultured mouse peritoneal macrophages of line J774G8. The affinity-purified epitopes identified by mAb A11 were recognised by human sera of cases of visceral leishmaniasis. The present study suggest that flagellar-specific epitopes mediate host-parasite interactions and, therefore, the role of these epitopes in the disease process is speculated.