Signal transduction events in human peripheral blood mononuclear cells stimulated by Schistosoma mansoni antigens

Activation of protein tyrosine kinases (PTKs) is a common step of T cell st imulation. However, the relationship between PTKs and activation of periphe ral blood mononuclear cells (PBMC) from intestinal chronic schistosomiasis patients has not been explored yet. In this study, we investigated the part icipation of Lck and ZAP-70 protein tyrosine kinases (PTKs), as well as PLC -yl and Shc proteins in PBMC activation by Shistosoma mansoni antigens. PBM C were stimulated with SEA (soluble egg antigen) or SWAP (soluble worm prep aration), lysed, precipitated with specific antibodies and the level of tyr osine phosphorylation evaluated. Our results show that Lck and Shc were pho sphorylated upon stimulation of the cells with SWAP, as well as with SEA. H owever, the phosphorylation level was more pronounced in SWAP than in SEA-s timulated cells. Phosphorylation of ZAP-70 was observed only in SWAP stimul ated cells. Additionally, PLC-gammal phosphorylation was not observed in PB MC stimulated with SEA:. Together, these results indicate that SEA and SWAP induce PBMC proliferation through distinct intracellular signaling pathway s. Moreover, the weaker response of PBMC to SEA compared to SWAP stimulatio n suggests down-regulation of cells from intestinal chronic schistosomiasis patients to SEA, which may occur during immunomodulation to S. mansoni res ponse. (C) American Society for Histocompatibility and Immunogenetics, 2001 . Published by Elsevier Science Inc.