Surface enolase is a virulence factor of Leishmania amazonensis metacyclic promastigotes involved in adhesion to macrophages.

We find that enolase, an evolutionarily conserved and multifunctional protein, is displayed on the cell surface of Leishmania amazonensis parasites in a developmentally regulated manner, associated with infectivity. Leishmania surface enolase acts as a parasite virulence factor. Specifically, surface exposure of enolase is limited to the infective metacyclic promastigote form in viable parasites. Correspondingly, L. amazonensis surface enolase plays a role specifically in the adhesion of parasites to host macrophages, the target cell type for productive infection. Surface enolase also may be involved in triggering the immunologically quiescent host response associated with early L. amazonensis infection. The display of enolase on the L. amazonensis promastigote parallels its exposure on the surface of apoptotic cells of metazoans as well as on the surface of bacteria and other pathogens that appear to mimic apoptotic cells. As in the case of enolase displayed on the apoptotic cell surface, externalized Leishmania enolase lacks glycolytic enzymatic activity. Our data reinforce the view that surface enolase functions significantly in the interaction of viable host cells with apoptotic corpses and with pathogens that exploit apoptotic mimicry.