Recognition of different Schistosoma mansoni antigens by specific human T cell clones

Human T lymphocyte clones (TLC) sensitized to Schistosoma mansoni soluble egg antigens (SEA) were developed from chronic schistosomiasis mansoni patients in order to investigate the regulatory mechanisms involved with in vitro granulomatous hypersensitivity to this parasite. All clones studied displayed CD4+ phenotype and required antigen-presenting cells in antigen-driven proliferation and granuloma formation. Each T lymphocyte clone has been shown to proliferate and generate in vitro granulomas in response to SEA, adult worm antigens (SWAP), or cercaria antigens (CAP). In contrast, no proliferation was observed in any of these T cell clones when unrelated S. mansoni antigens were used. Some SEA-generated TLC were not able to proliferate in the presence of SEA; however, S. mansoni SEA-reactive ones were able to recognize epitopes in Schistosoma japonicum SEA, indicating cross-reactivity between these two species. Using IFN-gamma ELISA, it was shown that TLC cells stimulated with SEA can secrete appreciable amount of this lymphokine. Further in vitro studies with these SEA-TLC will help us to understand in more depth the role of regulatory T cells in the human granulomatous hypersensitivity to S. mansoni eggs.