An In Vitro Study on Suppressive Effects of Leishmania major on IL-2Ra Expression in Activated Peripheral Human T Lymphocyte

Leishmaniasis is a parasitic disease which caused by a protozoan belong to the genus، Leishmania. IL-2 is an important cytokine that progresses lymph-ocytes from G1 to S phase، leading to T cells growth and proliferation. IL-2 is produced by activated CD4+ T cells and stimulates T and B lymphocytes، monocy-tes and natural killer cells. The present study was designed to determine and define the leishmania major-induced suppression of IL-2Rα expression in the peripheral human T-lymphocytes in vitro condition. Leishmania major standard strain (MRHO/IR/75/EK) was cul-tured in the NNN medium and proliferated in RPMI medium. Human peripheral T lymphocytes were also cultured in RPMI medium. Phytohemaglutinin-stimulated lymphocytes، in the present and/or absent of leishmania major promastigotes، were sam-pled at the incubation times، 12، 24، 36، 48h، stained with FITC-labelled anti-CD25 (IL-2Rα chain MAb) and PE-labelled anti-CD4 (CD4 MAb) and then، analyzed by flowcytometry. Data were analyzed by us-ing the WIN MDI software and statistical tests. Results of this study showed that leishmania major suppressed the expression of IL-2R in the activated T cells and inhib-ited the proliferation of lymphocytes. We found the expression of IL-2R by human peripheral T Lymphocytes. These T cells that co-cultured with leishmania major and stimulated with Phytohemagglutinin، were significantly suppressed 6h after culture initiation. However، the suppressed effect was seen to be moderate. The magnitude of this effect further increased when greater numbers of promastigotes were added. Discussion & Inhibition of IL-2R expression by the leishmania parasite may play a role in the suppressive effects associated with leishmaniasis disease. Molecular and biochemical characterization of the leishmania immuno suppressive fac-tors can be useful for vaccine development and also for drug related studies.