Leishmania infantum nucleoside triphosphate diphosphohydrolase 1 (NTPDase 1) B-domain: Antibody antiproliferative effect on the promastigotes and IgG subclass responses in canine visceral leishmaniasis.

A nucleoside triphosphate diphosphohydrolase-1 (NTPDase 1) was identified on the surface, flagellum and kinetoplast from L. infantum promastigotes by immunocytochemistry and confocal laser scanning microscopy, using immune sera that recognized specifically the B domain of NTPDase 1 and produced against synthetic peptides (LbB1LJ and LbB2LJ) derived from this domain. The polyclonal antibodies had effective antileishmanial effect, reducing significantly in vitro promastigotes growth (21-25%), an antiproliferative effect also demonstrated by immune sera produced against recombinant r-pot B domain, and two other synthetic peptides (potB1LJ and potB2LJ). In addition, using these biomolecules in ELISA technique, IgG1 and IgG2 subclasses reactivities of either healthy dogs or infected by L. infantum and classified clinically as asymptomatic, oligosymptomatic and symptomatic were tested. Analysis of distinct IgG1 and IgG2 seropositivities patterns suggested antibody subclasses binding epitopes along B domain for protection against infection, indicating this domain as a new tool for prophylactic and immunotherapeutic investigations.