T cell response of asymptomatic Leishmania chagasi infected subjects to recombinant leishmania antigens

In areas of Leishmania chagasi transmission the ability to control leishman ia infection is associated with IFN-gamma In visceral leishmaniasis down-re gulation of T cell responses is mediated by interleukin-10 (IL-10). In this study we evaluated the lymphoproliferative response, IFN-gamma and IL-10 p roduction on lymphocyte cultures stimulated with recombinant leishmania ant igens in subjects with asymptomatic L. chagasi infection. There was a stati stically significant difference in the lymphoproliferative response of the subjects with asymptomatic infection as compared to patients with visceral leishmaniasis and healthy subjects with respect to crude antigens (p<0.01), gp-63 (p<0.05) and hsp-70 (p<0.01), as well as between asymptomatic L. cha gasi infected subjects and patients with visceral leishmaniasis with respec t to the response to all antigens tested. The IFN-gamma production observed in the group with asymptomatic infection with all the three recombinant an tigens tested was higher (p<0.01) than that observed in patients with visce ral leishmaniasis and in healthy subjects. Furthermore, in individuals with asymptomatic infection, IL-IO levels in cultures stimulated with recombina nt antigens were very low This study shows that lymphocytes from individual s with asymptomatic L. chagasi infection are able to recognize recombinant leishmania antigens with production of a cytokine that is associated with l eishmania killing.