CD8 cytotoxic T cells in cutaneous leishmaniasis.

CD8 T cells are essential in the defence against viruses, yet little is known of their participation in the host defence against parasites, such as Leishmania, which can cause a variety of clinical diseases, such as localized cutaneous, diffuse cutaneous, mucocutaneous and visceral leishmaniasis. Murine models of leishmaniasis suggest that CD8 T cells participate through IFN-gamma production, yet their cytotoxic capacity also plays an important role, as has been found in patients infected with various Leishmania strains, where CD8 T cell cytotoxicity and apoptosis of autologous Leishmania-infected macrophages correlate with cure. Yet the mechanisms underlying the CD8 T activation in patients with leishmaniasis remain an enigma. It is possible that dendritic cells activate CD8 T cells through mechanisms that include antigen cross-presentation. Here we summarize the recent findings of CD8 T cells in cutaneous leishmaniasis and discuss their significance in the control of the disease. Further knowledge in this field will undoubtedly improve the design of therapeutic and vaccine strategies.