An in vitro study on suppressive effects of Leishmania major on IL-2Rα expression on peripheral human T lymphocyte

Leishmania sp. is an intracellular protozoan parasite that causes significant morbidity and mortality in many parts of the world. The parasite can escape from host immune system by several mechanisms. Understanding biological behavior of the parasite can help us to control and treatment leishmaniasis. Therefore current study was conducted to determine suppresive effect of Leishmania major on IL-2Rα expression in the human peripheral T Lymphocytes. Human peripheral T Lymphocyte were co-cultured with standard strain of Leishmania major (MRHO/IR/75/EK) in RPMI1640 medium. Infected cells were stained with FITC-labelled anti-CD25 (IL-2Rα chain MAb) and Picoerithrin-labelled anti-CD4 (CD4 MAb) and analyzed by flow cytometry. The results showed that L. major suppressed IL- 2Rα expression in activated T cells as well as inhibited lymphocyte proliferation 6h after infection and was increased up to 36 hour later. This finding also indicated that suppressed IL- 2R expression was increased when the number of promastigote was added up to 7.5×10(6) cells/ml. Inhibition of IL-2R expression by the parasite might play a critical role for escaping from host immune system. Understanding biological characterization of the Leishmania can be useful for vaccine development and also cytokine therapy.