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Journal of Parasitology Research
Volume 2012, Article ID 930257, 12 pages
Review Article

Toll-Like Receptors in Leishmania Infections: Guardians or Promoters?

Instituto de Biofisica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Bloco G, CCS, Ilha do Fundão, Cidade Universitária, Rio de Janeiro 21941-902, RJ, Brazil

Received 31 August 2011; Revised 1 December 2011; Accepted 6 December 2011

Academic Editor: Dario Zamboni

Copyright © 2012 Marilia S. Faria et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Protozoa of the genus Leishmania cause a wide variety of pathologies ranging from self-healing skin lesions to visceral damage, depending on the parasite species. The outcome of infection depends on the quality of the adaptive immune response, which is determined by parasite factors and the host genetic background. Innate responses, resulting in the generation of mediators with anti-leishmanial activity, contribute to parasite control and help the development of efficient adaptive responses. Among those, the potential contribution of members of the Toll-like receptors (TLRs) family in the control of Leishmania infections started to be investigated about a decade ago. Although most studies appoint a protective role for TLRs, there is growing evidence that in some cases, TLRs facilitate infection. This review highlights recent advances in TLR function during Leishmania infections and discusses their potential role in restraining parasite growth versus yielding disease.