title: The effects of antithymocyte globulin on natural killer cells.
abstract: We studied the effects of antithymocyte globulin (ATG) on natural killer (NK) cell activity to evaluate whether ATG may be useful in preventing NK-mediated disorders such as rejection of mismatched bone marrow (BM). We found that four of four lots of ATG eliminated greater than 95% of NK activity against K562. The effect of ATG on NK-mediated suppression of granulocyte-macrophage colony-forming units (CFU-GM) was also studied. ATG at a concentration of 1.0 mg/ml completely abrogated NK-mediated suppression of CFU-GM, as did monoclonal antibody Leu 11b/anti-CD 16 and complement (BRC). In contrast, OKT3/anti-CD3 had no effect on NK-mediated suppression of CFU-GM, suggesting that the effector cells were most likely NK cells rather than T cells. We also studied the effect of gamma interferon (INF) on NK-mediated suppression of CFU-GM and showed that eliminating NK cells with Leu 11b and BRC or ATG did not reduce gamma INF suppression of CFU-GM, suggesting that gamma INF directly suppressed CFU-GM rather than augmenting NK activity. Based on these results we postulate that ATG may have a role in the prevention or treatment of suppression of hematopoiesis thought to be caused by NK cells.
mesh_terms: D003114:Colony-Forming Units Assay; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007518:Isoantibodies / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects*
chemical_list: D007518:Isoantibodies; C035678:anti-Thy antibody; D007371:Interferon-gamma