title: Binding of toxic-shock-syndrome toxin-1 to human peripheral blood mononuclear cells.
abstract: Toxic-shock-syndrome toxin-1 (TSST-1), produced by Staphylococcus aureus and associated with toxic shock syndrome, functions in vitro as both a lymphoproliferative and immunosuppressive protein for human peripheral blood mononuclear cells (PBMs). We analyzed TSST-1-target cell interactions by receptor-ligand binding analyses. In competitive binding experiments, 2 X 10(5) human PBMs or purified cell populations were incubated in the presence of small amounts of (5-50 ng) of 125I-labeled TSST-1 and increasing amounts of unlabeled TSST-1 (25-10,000 ng). Data were analyzed by the method of Scatchard. Toxin-specific receptors were shown to exist on T lymphocytes within the PBM population. T4+ cells had 27.5 X 10(6) receptors per cell, and T8+ cells had 9 X 10(6) receptors per cell. T4+ and T8+ receptors had dissociation constants of 2.58 X 10(-8) M and 1.8 X 10(-8) M, respectively. These studies confirm earlier work showing that TSST-1 causes the functional activation of a population of T lymphocytes involved in suppression of immunoglobulin responses.
mesh_terms: D001427:Bacterial Toxins; D001667:Binding, Competitive; D003208:Concanavalin A / Q000494:pharmacology; D004768:Enterotoxins / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D018089:Superantigens; D013696:Temperature
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D007457:Iodine Radioisotopes; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal; D003208:Concanavalin A