title: Biologic characteristics of an immunosuppressive factor derived from a human lung cancer cell line.
abstract: A 549, a human lung cancer cell line, spontaneously produces a tumor-derived immunosuppressive factor (TDSF) which inhibited PHA-stimulated T lymphocyte proliferation via a noncytotoxic mechanism. The inhibition increased in a dose-dependent pattern. The factor also markedly suppressed production of interleukin (IL-2) by PHA-stimulated lymphocytes and IL 2-dependent proliferation of activated lymphocytes. The fact that TDSF possessed very potent inhibitive action on IL-2 is especially noteworthy if we consider the use of IL-2 as immunotherapeutic agent. The synthesis of the factor was inhibited by mitomycin C, actinomycin D and cycloheximide, indicating that the factor is a genic product of A 549 cells. The factor is chemically a protein with a molecular weight greater than 150 KD and sensitive to extremes of pH, heating to 60 degrees C and trypsin treatment.
authors.forename: R D
authors.initials: RD
authors.lastname: Wang
authors.forename: Z C
authors.initials: ZC
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Luo
authors.forename: Z H
authors.initials: ZH
authors.lastname: Feng
mesh_terms: D006023:Glycoproteins / Q000302:isolation & purification*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D008175:Lung Neoplasms / Q000032:analysis / Q000276:immunology* / Q000473:pathology; D009363:Neoplasm Proteins / Q000302:isolation & purification*; D013601:T-Lymphocytes / Q000276:immunology*; D014407:Tumor Cells, Cultured / Q000032:analysis
chemical_list: D006023:Glycoproteins; D007376:Interleukin-2; D009363:Neoplasm Proteins; C038588:serum immunosuppressive factor, human