Human T Cell Surface Antigens Bearing a Structural Relationship to HLA Antigens

Three cell surface antigens that are structurally related to the human major histocompatibility antigens (called HLA antigens) have been characterized from the leukemic T cell line MOLT-4. One antigen is a glycoprotein of Mr49,000 recognized by two monoclonal antibodies, OKT6 and NA1/34, and is associated with a Mr12,000 subunit that crossreacts serologically with β2-microglobulin but can be distinguished from it by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. A second antigen, defined by the monoclonal antibody OKT10, is a Mr46,000 protein associated with a small subunit distinct from β2-microglobulin. The OKT10 antigen is not restricted to T cells and is found on all T and B lymphoblastoid cell lines tested. The third protein is a β2-microglobulin-associated glycoprotein of Mr43,000 that is serologically distinct from the OKT6 (NA1/34), OKT10, and HLA antigens. It is found on some, but not all, T cell lines but is absent from any other hematopoeitic cell lines tested.