Role of Toll-like receptors in the response of human macrophages to Leishmania panamensis infection (133.17)

Abstract

Abstract Background: The macrophage is both the host and effector phagocytic cell in the recognition and clearence of L. panamensis parasites. The contribution of Toll-like receptors (TLRs) in the outcome of infection is unknown in American cutaneous leishmaniasis. Objetive: The aim of this study is to determine whether TLRs have a role in the recognition of L. panamensis and identify which TLRs are involved in the response in human macrophages. Methods: TNFα production and cellular expression of TLRs were measured in human primary macrophages from healthy donors in response to TLRs ligands and to the infection with L. panamensis promastigotes. Production of TNFα in TLR positive and TLR knockout murine macrophages was determined in response to promastigotes and amastigotes of L. panamensis. Results and Conclusion: L. panamensis induced a variable production of TNFα by human macrophages from different donors with the same kinetics and similar level as TLR ligands. Expression of TLR1, TLR2, TLR3 and TLR4 in macrophages increased during L. panamensis infection. Activation of wild-type mouse macrophages indicated a possible role of TLRs in the innate recognition of Leishmania. Activation of TLR2 by promastigotes but not by amastigotes suggests a possible role for TLR2 in the recognition and outcome of infection.