Negative selection of precursor thymocytes before their differentiation into CD4+CD8+ cells.
Thymic selection of the developing T cell repertoire is thought to occur at the CD4+CD8+ stage of differentiation and to be determined by the specificity of the T cell receptors (TCRs) that CD4+CD8+ thymocytes express. However, TCR signals can inhibit the differentiation of precursor thymocytes into CD4+CD8+ cells, which suggests that selection might occur earlier than thought. Indeed, in a negatively selecting male thymus, CD4-CD8lo precursor thymocytes that express a transgenic TCR to male antigen are developmentally arrested as a consequence of antigen encounter and fail to become CD4+CD8+. Thus, negative selection can occur before the CD4+CD8+ stage of differentiation.
Takahama
Y
Y
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Shores
E W
EW
Singer
A
A
D000818:Animals; D015704:CD4 Antigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D016827:CD8 Antigens / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D008297:Male; D051379:Mice; D008822:Mice, Transgenic / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell