Superantigen-driven peripheral deletion of T cells. Apoptosis occurs in cells that have lost the alpha/beta T cell receptor.
Injection of lymphoid cells expressing minor lymphocyte-stimulating antigen-1 (Mls-1a) induces tolerance to the superantigen, and partial deletion of Mls-1a-reactive T cells. We have identified a transient population of T cells that have lost the alpha/beta T cell receptor at the time when Mls-1a-reactive T cells start to disappear during the process of tolerance induction. Apoptosis was directly demonstrated in this TCR-alpha/beta negative T-cell population. This indicates a peripheral T-cell deletion pathway, characterized by TCR down-regulation, apoptosis, and clonal deletion. The consequence of Mls-1a-induced TCR down-regulation appears to be different in CD4+ cells and in CD8+ cells. Although most of the CD4+ cells that have lost TCR expressing alpha- and beta-chains appear to be undergoing apoptosis, many of their CD8+ counterparts may be able to re-express the Ag receptor. This argues for the involvement of coreceptors in the induction of apoptosis during peripheral deletion.
Huang
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Section of Immunobiology, Yale University Medical School, New Haven, CT 06510.
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D000818:Animals; D017209:Apoptosis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D015536:Down-Regulation; D007108:Immune Tolerance; D008212:Lymphocyte Depletion; D051379:Mice; D008815:Mice, Inbred Strains; D016747:Minor Lymphocyte Stimulatory Antigens / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*
D015704:CD4 Antigens; D016827:CD8 Antigens; D016747:Minor Lymphocyte Stimulatory Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta