Heterogeneity of antigen-specific CD4+ T cell clones from a patient with Schistosomiasis mansoni

Phenotype and cytokine profile of Schistosoma mansoni specific T cell lines and clones derived from schistosomiasis patients with distinct clinical forms

It is essential to distinguish the role of T lymphocytes on the physiopathology associated to more severe forms of schistosomiasis and on the immunomodulation that evolves in the majority of infected people. In this study, we generated Schistosoma mansoni-specific T cell lines and clones from patients with the acute and chronic (intestinal and hepatosplenic forms) phases of disease, from former ones, and from uninfected individuals sensitized to parasite soluble antigens. T cell lines derived from nontreated acute infected donors were capable of producing IL-4 and IL-5, while cells from treated patients secreted IFN-gamma. Lines from intestinal chronic and antigen-sensitized donors preferentially produced IFN-gamma, while those from hepatosplenic patients secreted all three cytokines. The cytokine analysis of CD4+ T cell clones revealed a Th2/Th0 pattern (clones producing IL-4 and IL-5 and clones producing all three cytokines) for those derived from infected patients, while cells from antigen-sensitized donors exhibited an opposite Th1/Th0 pattern (clones producing IFN-gamma and clones producing all three cytokines). The possible role of these T cell populations on human schistosomiasis mansoni is discussed.

Characterization of Schistosoma mansoni specific human T-T hybrids

In this study, we generated antigen-specific T-T hybrids by the fusion of an established T lymphoma, CEM, with T-cell lines derived from Schistosoma mansoni antigen-stimulated peripheral blood mononuclear cells (PBMC) of schistosomiasis patients. These PBMC were capable of in vitro proliferation and granuloma formation upon proper stimulation with antigens derived from different phases of S. mansoni development. Culture supernatants collected from T-T hybrids were responsible for the stimulation or inhibition of antigen-specific responses of other PBMC, on in vitro proliferation and granuloma reaction assays. Clones derived from a T-T hybrid were characterized as CD4+ CD8- HLA-DR- and expressed the cellular markers CD3 and CD25, especially after antigenic stimulation. Their supernatants, as that from the T-T hybrid line, were capable of modulation of in vitro cellular responses, and IL-2, IL-10, and TNF-alpha were detected upon cellular stimulation with antigen or phytohemagglutinin-A (PHA).

Cytokine profile associated to effector functions of human T cell clones specific for Schistosoma mansoni antigens

T cell lines and clones specific for Schistosoma mansoni antigens were established to study cellular immunity in human schistosomiasis. Flow cytometric analysis of the clones demonstrated that all of them were of the helper inducer T cell subset (CD3+, CD4+, CD8-), and expressed the alphabeta T cell receptor, besides the IL-2 low affinity receptor CD25. Lymphokine analysis revealed that clones presented Th1, Th2, or either Th0 patterns of secretion. More interestingly, the capability of clones to induce in vitro granuloma reactions seems to be related to the presence of TNF-alpha and the absence of IL-10. In counterpart, IL-10 producer clones did not help in vitro granuloma formation, even in the presence of TNF-alpha.