title: T cell receptor-mediated recognition of self-ligand induces signaling in immature thymocytes before negative selection.
abstract: Shaping of the T cell repertoire by selection during intrathymic maturation involves T cell receptor (TCR) recognition of major histocompatibility complex/self-antigen complexes. In this communication, we studied the ability of minor lymphocyte stimulating (Mls) determinants to act as self-tolerogens in the selection of the T cell repertoire. We demonstrate that unprimed T cells from normal as well as TCR transgenic mice form Mls-specific conjugates with antigen-presenting cells, and that this TCR-ligand interaction leads to elevation of intercellular Ca2+ ([Ca2+]i). Peripheral T cells from TCR transgenic mice expressing receptors specific for self-Mls antigen show no reactivities to Mlsa. However, a proportion of immature thymocytes from these mice show specific binding and strong [Ca2+]i elevation in response to self-antigen-presenting cells, although these thymocytes do not proliferate. This self-reactivity of thymocytes is inhibited by antibodies specific for TCR, CD4, CD8, class II molecules, lymphocyte function-associated antigen 1, and intercellular adhesion molecule 1. These results demonstrate for the first time that before thymic negative selection, immature T cells can specifically interact with cells bearing self-antigen, and suggest that the resulting TCR-dependent signal transduction events provide a basis for negative selection of self-reactive T cells.
authors.affiliation: Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: R
authors.initials: R
authors.lastname: Abe
authors.forename: Y
authors.initials: Y
authors.lastname: Ishida
authors.forename: K
authors.initials: K
authors.lastname: Yui
authors.forename: M
authors.initials: M
authors.lastname: Katsumata
authors.forename: T M
authors.initials: TM
authors.lastname: Chused
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000276:immunology; D002454:Cell Differentiation; D005434:Flow Cytometry; D007108:Immune Tolerance; D008024:Ligands; D051379:Mice; D008808:Mice, Inbred CBA; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
chemical_list: D001324:Autoantigens; D008024:Ligands; D011948:Receptors, Antigen, T-Cell