Browsing by Author "Juliano Neto, Luiz"

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    An antigenic domain within a catalytically active leishmania infantum nucleoside triphosphate diphosphohydrolase (NTPDase 1) is a target of inhibitory antibodies.
    (2013) Maia, Ana Carolina Ribeiro Gomes; Porcino, Gabriane Nascimento; Detoni, Michelle de Lima; Emídio, Nayara Braga; Marconato, Danielle Gomes; Pinto, Priscila de Faria; Fessel, Melissa Regina; Reis, Alexandre Barbosa; Juliano Neto, Luiz; Juliano, Maria Aparecida; Marques, Marcos José; Vasconcelos, Eveline Gomes
    Weidentified a shared B domainwithin nucleoside triphosphate diphosphohydrolases (NTPDases) of plants and parasites. Now, an NTPDase activity not affected by inhibitors of adenylate kinase and ATPases was detected in Leishmania infantum promastigotes. By non-denaturing gel electrophoresis of detergent-homogenized promastigote preparation, an active band hydrolyzing nucleosides di- and triphosphate was visualized and, following SDS-PAGE and silver staining was identified as a single polypeptide of 50 kDa. By Western blots, it was recognized by immune sera raised against potato apyrase (SA), r-pot B domain (SB), a recombinant polypeptide derived fromthe potato apyrase, and LbB1LJ (SC) or LbB2LJ (SD), synthetic peptides derived fromthe Leishmania NTPDase 1, and by serum samples from dogs with visceral leishmaniasis, identifying the antigenic L. infantum NTPDase 1 and, also, its conserved B domain (r83–122). By immunoprecipitation assays andWestern blots, immune sera SA and SB identified the catalytically active NTPDase 1 in promastigote preparation. In addition, the immune sera SB (44%) and SC or SD (87–99%) inhibited its activity, suggesting a direct effect on the B domain. By ELISA, 37%, 45% or 50% of 38 infected dogs were seropositive for r-pot B domain, LbB1LJ and LbB2LJ, respectively, confirming the B domain antigenicity.
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    Leishmania infantum nucleoside triphosphate diphosphohydrolase 1 (NTPDase 1) B-domain : antibody antiproliferative effect on the promastigotes and IgG subclass responses in canine visceral leishmaniasis.
    (2019) Maia, Ana Carolina Ribeiro Gomes; Porcino, Gabriane Nascimento; Pinto, Priscila de Faria; Mendes, Túlio Vieira; Antinarelli, Luciana Maria Ribeiro; Coimbra, Elaine Soares; Reis, Alexandre Barbosa; Juliano Neto, Luiz; Juliano, Maria Aparecida; Marques, Marcos José; Vasconcelos, Eveline Gomes
    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.