title: Homeostatic competition among T cells revealed by conditional inactivation of the mouse Cd4 gene.
abstract: Absence of CD4 impairs the efficiency of T cell receptor (TCR) signaling in response to major histocompatibility complex (MHC) class II-presented peptides. Here we use mice carrying a conditional Cd4 allele to study the consequences of impaired TCR signaling after the completion of thymocyte development. We show that loss of CD4 decreases the steady-state proliferation of T cells as monitored by in vivo labeling with bromo-deoxyuridine. Moreover, T cells lacking CD4 compete poorly with CD4-expressing T cells during proliferative expansion after transfer into lymphopenic recipients. The data suggest that T cells compete with one another during homeostatic proliferation, and indicate that the basis of this competition is TCR signaling.
authors.affiliation: Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA 94143-0414, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Strong
authors.forename: N
authors.initials: N
authors.lastname: Killeen
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D008285:Major Histocompatibility Complex / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology
chemical_list: D015704:CD4 Antigens; D011948:Receptors, Antigen, T-Cell