The human T-cell receptor.
Recent studies using cloned antigen-specific T lymphocytes and monoclonal antibodies directed at their various surface glycoprotein components have led to the identification of the human T-cell antigen receptor as a surface complex comprised of a clonotypic 90-kD Ti heterodimer and the invariant 20- and 25-kD T3 molecules. Approximately 30,000-40,000 Ti and T3 molecules exist on the surface of human T lymphocytes. These glycoproteins are acquired and expressed during late thymic ontogeny, thus providing the structural basis for immunologic competence. The alpha and beta subunits of Ti bear no precursor-product relationship to one another and are encoded by separate genes. Moreover, the presence of unique peptides following proteolysis of different Ti molecules isolated by non-cross-reactive anticlonotypic monoclonal antibodies supports the notion that variable regions exist within both the alpha and the beta subunits. N-Terminal amino acid sequencing and molecular cloning of the Ti beta subunit further show that it bears an homology to the first V-region framework of immunoglobulin light chains and represents the product of a gene that rearranges specifically in T lymphocytes. Triggering of the T3-Ti receptor complex gives rise to specific antigen-induced proliferation through an autocrine pathway involving endogenous IL-2 production, release, and subsequent binding to IL-2 receptors. The implications of these findings for understanding human T-cell growth and its regulation in disease states are discussed.
O
O
Acuto
M
M
Fabbi
A
A
Bensussan
C
C
Milanese
T J
TJ
Campen
H D
HD
Royer
E L
EL
Reinherz
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000954:Antigens, Surface / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D002999:Clone Cells; D000939:Epitopes / Q000032:analysis; D005796:Genes; D006801:Humans; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000954:Antigens, Surface; D000939:Epitopes; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell