title: Effect of a synthetic thymic factor (facteur thymique serique) on natural killer cell activity in humans.
abstract: The effect of the serum thymic factor, FTS, on human NK cells was studied. NK cell activity was measured in a 51Chromium-release assay in which effector cells were peripheral blood lymphocytes (PBL) or bone marrow (BM) lymphocytes from healthy individuals and patients, and targets were K562 cells. When added in vitro in this assay, FTS modulated NK cell activity of normal PBL. Low concentrations of FTS (10(-2) ng/ml) increased NK activity (P less than 0.001) whereas higher concentrations decreased it (P less than 0.01) for 10 and 10(2) ng/ml. FTS exhibited no effect on NK cell activity of BM lymphocytes. When administered in vivo to 4 cancer patients (10 micrograms/kg i.v. every 3 days), FTS progressively increased peripheral NK activity in two patients with low pre-treatment NK values, whereas it decreased NK activity in two patients with previously normal or high NK values. The mechanism by which FTS modulates NK cell activity is still unknown but such modulation suggests that NK cells belong in part to the T-lineage.
mesh_terms: D001854:Bone Marrow Cells; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D006728:Hormones; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D007372:Interferons / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects*; D007962:Leukocytes / Q000276:immunology*; D013935:Thymic Factor, Circulating / Q000494:pharmacology*; D013951:Thymus Hormones / Q000494:pharmacology*
chemical_list: D006728:Hormones; D013951:Thymus Hormones; D007372:Interferons; D013935:Thymic Factor, Circulating