title: CD4 and the immunoglobulin superfamily.
abstract: The CD4 membrane glycoprotein was one of the first cell surface antigens to be identified using monoclonal antibodies. It was shown to have a central role in the control of the recognition of foreign proteins by T lymphocytes and later as a receptor for the human immunodeficiency virus (HIV). The analysis of the amino acid sequence of CD4 showed that the extracellular region comprised four regions with sequence similarities to immunoglobulin domains. The structure of domains 3 and 4 of CD4 has been determined by X-ray crystallography and, like domains 1 and 2 previously determined, these have typical immunoglobulin-like folds. The results are discussed with respect to the identification of other domains with immunoglobulin-like folds from amino acid sequence data, and the evolution of CD4.
authors.affiliation: MRC Cellular Immunology Unit, Sir William Dunn School of Pathology, University of Oxford, U.K.
authors.forename: A N
authors.initials: AN
authors.lastname: Barclay
authors.forename: R L
authors.initials: RL
authors.lastname: Brady
authors.forename: S J
authors.initials: SJ
authors.lastname: Davis
authors.forename: G
authors.initials: G
authors.lastname: Lange
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry*; D005075:Biological Evolution; D015704:CD4 Antigens / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry; D007145:Immunoglobulin kappa-Chains / Q000737:chemistry; D007146:Immunoglobulin lambda-Chains / Q000737:chemistry; D007136:Immunoglobulins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D051381:Rats; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
chemical_list: D015703:Antigens, CD; D015704:CD4 Antigens; D007143:Immunoglobulin Heavy Chains; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D007136:Immunoglobulins; D016693:Receptors, Antigen, T-Cell, alpha-beta