title: A 35 000 dalton T-cell supernatant protein associated with suppression of mitogenic responses.
abstract: Synthesis of a CEM T-lymphoblast supernatant protein of 35 000 daltons (p35), which is scarcely expressed on CEM membranes, increased 8-fold when cells were grown in crowded cultures. Synthesis of p35 was more dependent upon crowding of cells on the flask bottom (maximum at 2.0 X 10(6) cells/cm2) than upon cell density in the culture medium (maximum at 3.0 X 10(6) cells/ml). Growth medium containing p35 inhibited the response of normal peripheral blood lymphocytes to PHA and to Con A. Supernatant media lacking p35, collected from low-density CEM cultures of from RAJI B lymphoblastoid cells which were grown under low or high-density conditions, did not suppress mitogenic responses of normal lymphocytes. These experiments support the view that the p35 T-cell supernatant protein plays a regulatory role in cell proliferation and possibly in the immune system.
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000494:pharmacology; D008934:Mitogens / Q000037:antagonists & inhibitors*; D008970:Molecular Weight; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D008934:Mitogens; D010835:Phytohemagglutinins; D003208:Concanavalin A