Characterization of () oligopeptidase B and its role in macrophage infection.

spp. are parasitic protozoa that cause leishmaniasis, a disease endemic in 98 countries. promastigotes are transmitted by the vector and differentiate into amastigotes within phagocytic cells of the vertebrate host. To survive in multiple and hostile environments, the parasite has several virulence factors. Oligopeptidase B (OPB) is a serine peptidase present in prokaryotes, some eukaryotes and some higher plants. It has been considered a virulence factor in trypanosomatids, but only a few studies, performed with Old World species, analysed its role in virulence or infectivity. () is an important agent of cutaneous leishmaniasis in Brazil. The () OPB encoding gene has been sequenced and analysed but has never been expressed. In this work, we produced recombinant () OPB and showed that its pH preferences, and inhibition patterns are similar to those reported for () and () OPBs. Since is known to secrete OPB, we performed infection assays using the recombinant enzyme. Our results showed that active OPB increased infection by () when present before and throughout infection. Our findings suggest that OPB is relevant to () infection, and that potential drugs acting through OPB will probably be effective for Old and New World species. OPB inhibitors may eventually be explored for leishmaniasis chemotherapy.