title: Induction of tolerance in freshly isolated alloreactive CD4+ T cells by activated T cell stimulators.
abstract: Activated human T cells express major histocompatibility complex class II proteins, and their potential to present antigens to T cell clones has been documented extensively. The effect of such TT presentation on responder T cell clones has been shown to be the induction of tolerance, sometimes accompanied by activation. To investigate whether freshly isolated responder T cells are also susceptible to such induction of tolerance by activated T cells functioning as antigen-presenting cells (APC), we have used the capability of unprimed ex vivo T cells to respond in a proliferation assay in vitro to alloligands on professional APC. We show that purified human T cells ex vivo, when exposed to alloligand on activated T cells for primary allorecognition in vitro, fail to mount a proliferative response. Priming of responder CD4+ T cells with alloligand expressed on activated T cells results in the induction of nonresponsiveness to a subsequent challenge by competent allo-APC. This ability of activated, HLA-DR+ T cells to induce nonresponsiveness to subsequent challenge in bulk CD4+ T cell populations ex vivo has interesting implications for infections involving T cells such as human immunodeficiency virus.
authors.affiliation: National Institute of Immunology, New Delhi, India.
authors.forename: E
authors.initials: E
authors.lastname: Satyaraj
authors.forename: S
authors.initials: S
authors.lastname: Rath
authors.forename: V
authors.initials: V
authors.lastname: Bal
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006681:HLA-D Antigens / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D007156:Immunologic Memory; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation
chemical_list: D006681:HLA-D Antigens