title: Quantitation of serum suppressor factor, related to the erythrocyte receptor of human peripheral blood T lymphocytes as measured by radioimmunoassay.
abstract: A solid phase radioimmunoassay for a serum suppressor factor has been developed. The factor was previously purified from malignant ascites fluids and shown to be related to the sheep erythrocyte receptor of human peripheral blood T lymphocytes. This humoral suppressor factor has been termed suppressive E-receptor factor. Using this assay, it was demonstrated that both ascites fluids and sera derived from patients with solid tumors contain elevated levels of this factor compared to similar specimens from patients with a variety of nonmalignant diseases. The concentration of this SER factor does not correlate with serum immunoglobulin G levels but it does correlate with the ability of sera from individual patients to inhibit phytohemagglutinin-induced DNA synthesis by normal human peripheral blood T lymphocytes. Kinetically, this suppressive E-receptor factor directly competes with monoclonal antibody directed to the sheep erythrocyte receptor of human peripheral T lymphocytes and exhibits noncompetitive-type inhibition of DNA synthesis induced by phytohemagglutinin.
mesh_terms: D000911:Antibodies, Monoclonal; D001201:Ascites / Q000276:immunology; D004247:DNA / Q000096:biosynthesis; D004912:Erythrocytes / Q000166:cytology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D008222:Lymphokines / Q000032:analysis*; D009369:Neoplasms / Q000276:immunology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011863:Radioimmunoassay; D013491:Suppressor Factors, Immunologic; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D008222:Lymphokines; D010835:Phytohemagglutinins; D013491:Suppressor Factors, Immunologic; D004247:DNA