Physical association of CD4 and the T-cell receptor can be induced by anti-T-cell receptor antibodies.
CD4 can physically associate with the CD3-T-cell receptor complex as visualized in cocapping experiments. This association occurs when the T-cell receptor is cross-linked by certain anti-variable region antibodies that appear to induce a conformational change in the receptor such that it associate with CD4. Similar association has been observed in earlier studies with the same cloned helper T cell when the physiological ligand, antigen-class II major histocompatibility complex molecule, is bound by the T-cell receptor. The ability of anti-T-cell receptor antibodies to induce the T-cell receptor-CD4 association correlates with a 100-fold increase in the ability of the antibody to activate the T cell. This suggests that the complex of CD4 and the T-cell receptor act synergistically in T-cell activation, thus readily explaining the commonly observed association of CD4 expression with class II major histocompatibility complex-restricted antigen recognition. This association could also play a role in infection by human immunodeficiency virus.
Rojo
J M
JM
Department of Pathology, Yale University School of Medicine, New Haven, CT 06510.
Saizawa
K
K
Janeway
C A
CA
D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D017252:CD3 Complex; D002460:Cell Line; D006224:Cricetinae; D003432:Cross-Linking Reagents; D000939:Epitopes / Q000276:immunology; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008213:Lymphocyte Activation; D046911:Macromolecular Substances; D051379:Mice; D051381:Rats; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D013861:Thiocyanates
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D003432:Cross-Linking Reagents; D000939:Epitopes; D005452:Fluoresceins; D005456:Fluorescent Dyes; D000949:Histocompatibility Antigens Class II; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D013861:Thiocyanates; D016650:Fluorescein-5-isothiocyanate