Molecular identification of human T-lymphocyte antigens defined by the OKT5 and OKT8 monoclonal antibodies.
Three human lymphocyte differentiation antigens, specific of the entire T-cell population, of the helper/inducer T-cell subset, and of the cytotoxic/suppressor T-cell subset have been identified, using mouse monoclonal antibodies obtained from Dr. P. Kung. Various T-cell populations were radio-labelled, the antigens were isolated by immunoprecipitation with the monoclonal antibodies and the resulting immune complexes subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The OKT3 antigen, present on peripheral T-lymphocytes and on functionally mature thymocytes has been identified as an oligomeric protein, composed of 23,000 mol. wt subunits. The OKT4 antigen, specific for the helper/inducer subset, is a single protein of 53,000 mol. wt. The OKT8/OKT5 antigen, defining the cytotoxic/suppressor subpopulation is composed of two subunits of 31,000 and 33,000. From co-capping experiments and biochemical data, the hypothesis is established that OKT5 recognizes a dimer of 140,000 mol. wt and OKT8 recognizes a determinant present on both the monomer 70,000 and the dimer. This hypothesis could explain the OKT5- OKT8+ phenotype of some T-cells.
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000032:analysis*; D002462:Cell Membrane / Q000276:immunology; D011232:Chemical Precipitation; D002675:Child, Preschool; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007152:Immunologic Capping; D007158:Immunologic Techniques; D007223:Infant; D008970:Molecular Weight; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface