High levels of proinflammatory
cytokines such as IFN-γ and TNF are associated with tissue lesions in
cutaneous leishmaniasis (CL). We previously demonstrated that Schistosoma mansoni
antigens downmodulate the in vitro
cytokine response in CL. In the current study we evaluated whether S. mansoni
antigens alter monocyte and T-lymphocyte phenotypes in
leishmaniasis. Peripheral blood mononuclear cells of CL patients were cultured with L. braziliensis
antigen in the presence or absence of the S. mansoni
antigens rSm29, rSmTSP-2- and PIII. Cells were stained with
fluorochrome conjugated
antibodies and analyzed by flow cytometry. The addition of rSm29 to the cultures decreased the expression of
HLA-DR in nonclassical (CD14(+)CD16(++)) monocytes, while the addition of PIII diminished the expression of this molecule in classical (CD14(++)CD16(-)) and intermediate (CD14(++)CD16(+)) monocytes. The addition of PIII and rSmTSP-2 resulted in downmodulation of CD80 expression in nonclassical and CD86 expression in intermediate monocytes, respectively. These two
antigens increased the expression of CTLA-4 in CD4(+) T cells and they also expanded the frequency of CD4(+)CD25(high)Foxp3(+) T cells. Taken together, we show that S. mansoni
antigens, mainly rSmTSP-2 and PIII, are able to decrease the activation status of monocytes and also to upregulate the expression of modulatory molecules in T lymphocytes.