ABSTRACT
BACKGROUND: Leishmania parasites have been reported to interfere and even subvert their host immune responses to enhance their chances of survival and proliferation. Experimental Leishmania infection in mice has been widely used in the identification of specific parasite virulence factors involved in the interaction with the host immune system. Cysteine-proteinase B (CPB) is an important virulence factor in parasites from the Leishmania (Leishmania) mexicana complex: it inhibits lymphocytes Th1 and/or promotes Th2 responses either through proteolytic activity or through epitopes derived from its COOH-terminal extension. In the present study we analyzed the effects of Leishmania (Leishmania) amazonensis CPB COOH-terminal extension-derived peptides on cell cultures from murine strains with distinct levels of susceptibility to infection: BALB/c, highly susceptible, and CBA, mildly resistant. RESULTS: Predicted epitopes, obtained by in silico mapping, displayed the ability to induce cell proliferation and expression of cytokines related to Th1 and Th2 responses. Furthermore, we applied in silico simulations to investigate how the MHC/epitopes interactions could be related to the immunomodulatory effects on cytokines, finding evidence that specific interaction patterns can be related to in vitro activities. CONCLUSIONS: Based on our results, we consider that some peptides from the CPB COOH-terminal extension may influence host immune responses in the murine infection, thus helping Leishmania survival.
Subject(s)
Cysteine Proteases/immunology , Epitopes/immunology , Leishmania mexicana/immunology , Leishmania mexicana/pathogenicity , Leishmaniasis/immunology , Amino Acid Sequence , Animals , Base Sequence , Cysteine Proteases/genetics , Cytokines/biosynthesis , Epitopes/genetics , Epitopes/metabolism , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , Epitopes, T-Lymphocyte/metabolism , Female , H-2 Antigens/immunology , H-2 Antigens/metabolism , Leishmaniasis/parasitology , Lymph Nodes/immunology , Lymph Nodes/metabolism , Lymphocyte Activation/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred CBA , Molecular Sequence Data , Nitric Oxide/biosynthesis , Protein Binding/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolismABSTRACT
The antimalarial acitivity of hydroxyethylamines, synthesized from the reaction of intermediated hydroxyethypiperazines with benzenesulfonyl chlorides or benzoyl chlorides, has been evaluated in vitro against a W2 Plasmodium falciparum clone. Some of the nineteen tested derivatives showed a significant activity in vitro, thus turning into a promising new class of antimalarials. In addition, a molecular modeling study of the most active derivative (5l) was performed and its most probable binding modes within plasmepsin II enzyme were identified.
