Nelfinavir is effective in inhibiting the multiplication and aspartic peptidase activity of Leishmania species, including strains obtained from HIV-positive patients.

Objectives: There is a general lack of effective and non-toxic chemotherapeutic agents for leishmaniasis and there is as yet no study about the effect of HIV peptidase inhibitors (HIV PIs) on Leishmania/HIV-coinfected patients. In the present work, we performed a comparative analysis of the spectrum of action of HIV PIs on different Leishmania spp., including strains obtained from HIV-positive patients receiving or not receiving antiretroviral treatment.

HIV aspartyl peptidase inhibitors interfere with cellular proliferation, ultrastructure and macrophage infection of Leishmania amazonensis.

Background: Leishmania is the etiologic agent of leishmanisais, a protozoan disease whose pathogenic events are not well understood. Current therapy is suboptimal due to toxicity of the available therapeutic agents and the emergence of drug resistance. Compounding these problems is the increase in the number of cases of Leishmania-HIV coinfection, due to the overlap between the AIDS epidemic and leishmaniasis.

Roles of the endosymbiont and leishmanolysin-like molecules expressed by Crithidia deanei in the interaction with mammalian fibroblasts.

Crithidia deanei is an insect trypanosomatid that harbors a bacterial endosymbiont in its cytoplasm. In this work, we have demonstrated the influence of the endosymbiont on the interaction of C. deanei with mammalian fibroblasts, also implicating the surface leishmanolysin-like molecules of C.

Crithidia deanei: influence of parasite gp63 homologue on the interaction of endosymbiont-harboring and aposymbiotic strains with Aedes aegypti midgut.

The present study demonstrates that the endosymbiont of Crithidia deanei influences the expression of surface gp63 molecules. Ultrastructural immunocytochemical analysis shows the presence of the gp63-like protein in the protozoan flagellum and flagellar pocket, either attached to shed membranes or in a free form. This molecule is glycosylphosphatidylinositol (GPI) anchored to the plasma membrane as demonstrated by phospholipase C (PLC) treatment and cross-reacting determinant detection by immunoblotting.

Antileishmanial activity of MDL 28170, a potent calpain inhibitor.

Several calpain inhibitors are under development and some are useful agents against important human pathogens. We therefore investigated the effect of MDL 28170, a potent calpain inhibitor, on the growth of Leishmania amazonensis. After 48 h of treatment, the inhibitor exhibited a dose-dependent antileishmanial activity, with a 50% lethal dose (LD(50)) of 23.

Gp63-like molecules in Phytomonas serpens: possible role in the insect interaction.

In this study, we demonstrated that metallopeptidase inhibitors (EDTA, EGTA, and 1,10-phenanthroline) were able to arrest Phytomonas serpens growth in distinct patterns. This parasite released exclusively metallopeptidases to the extracellular environment, whereas in cellular extracts only cysteine peptidases were detected. In addition, an extracellular polypeptide of 60 kDa reacted in Western blotting probed with polyclonal antibody raised against gp63 of Leishmania amazonensis.