Abstract

LISCANO, Maria Gabriela; LONGA, Zahira; INFANTE, Mariangela  and  TELLES, Senobia. Evaluation of a Method for the Leishmania spp Natural Peptide Isolation. Salus [online]. 2011, vol.15, n.1, pp.23-28. ISSN 1316-7138.

The ability of macrophages to process and present Leishmania antigens is thought to be needed for their efficient interaction with effector T cells and locally-delivered cytokines which induce a leishmanicidal activity. T cell receptors (TCR) recognize antigenic peptides associated with the major histocompatibility complex (MHC) molecules, and this trimolecular interaction initiates antigen-specific signaling pathways in the responding T cells. In the development of vaccines for intracellular parasitic diseases, it is of pivotal importance the elucidation of the immunological mechanisms associated with them, particularly, the identification of peptides (T cell epitopes) that can stimulate a given TCR. Thus, we considered the possibility of identifying natural Leishmania spp peptides able to stimulate T cell subpopulations that produce a pattern of cytokines associated with disease protection. As a first step in the study, we used a method described by Malik and Strominger (2000), with significant modifications to isolate CMH/II-peptide complexes. For this purpose, a cell line of human monocytes were infected with promastigotes Leishmaniabraziliensis, and the expressed complexes were purified by immunoaffinity chromatography, and fractionated by RT-HPLC. The HPLC fractions obtained were tested for their capacity to stimulate a T cell proliferative response and cytokine secretion. Results obtained from peripheral blood mononuclear cells (PBMC) from Leishmania-infected patients showed an important reactivity with two of the fractions tested, while the rest of the fractions were unable to induce cell stimulation with the strategy used.

Keywords : Leishmaniasis; peptides; MHC.

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