Background and Aim: The heterogenous population of memory T lymphocytes is distinguished based on surface markers and effector functions such as cytokine secretion. Recently, two subsets of memory T cells are defined by expression of chemokine receptor CCR7 and CD45RA designating as "central memory" T cells (T_CM) and "effector memory" T cells (T_EM). The objective of this staudy was to evaluate the phenotype and function of these lymphocytes in healed cases of cutaneous leishmaniasis.
Methods: The phenotype of lymphocytes were determined in blood samples of 13 volunteers with history of self healing cutaneous leishmaniasis (HCL) and in 6 healthy controls.
Results: No significant difference was found in memory T cell subsets between HCL volunteers and healthy controls using flow cytometry. However, following sorting of different memory subsets, a significantly higher proliferation was seen in cells of HCL volunteers comparing to the control group. A significantly higher IFN-γ response in T_EM and a significantly higher IL-2 response in T_CM were observed in cell culture of HCL volunteers comparing controls.
Conclusion: The responses were elicited when the cells were stimulate with SLA in vitro, it is concluded Leishmania-specific T_EM and Leishmania-specific T_CM subsets exist in HCL volunteers and since the volunteers with history of CL presumed to be protected against reinfection, it seems that both T_CM and T_EM play role in the protection against Leishmania infection in these individuals.