title: A basophil-activating factor from human T lymphocytes.
abstract: Human T lymphocytes stimulated with phytohaemagglutinin (PHA) or streptokinase-streptodornase (SK-SD) generate an activity which elicits non-cytotoxic histamine release from human basophils. Filtration of the T lymphocyte-derived activity on columns of Sephadex G-100 and Fractogel 55F sequentially revealed one predominant basophil-activating factor of mol. wt. 70,000-90,000, that was designated BAF-T. BAF-T was composed of two acidic proteins of approximate pI 4.4 and 5.2-5.5, as assessed by isoelectric focusing. The distinction of BAF-T from IgE was confirmed by the failure of BAF-T to bind to an anti-IgE affinity column and the capacity of BAF-T to release histamine maximally from basophils desensitized to IgE-dependent stimuli. The inability of BAF-T to release histamine from human lung mast cells and dog cutaneous mastocytoma cells suggests target cell specificity. The source and activity of BAF-T are consistent with a specific contribution of this mediator to human cellular immune and hypersensitivity responses involving T lymphocytes and basophils.
mesh_terms: D001491:Basophils / Q000276:immunology*; D002850:Chromatography, Gel; D006133:Growth Substances / Q000096:biosynthesis*; D006636:Histamine Release; D006801:Humans; D008213:Lymphocyte Activation; D008970:Molecular Weight; D010835:Phytohemagglutinins / Q000494:pharmacology; D013299:Streptodornase and Streptokinase / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006133:Growth Substances; D010835:Phytohemagglutinins; D013299:Streptodornase and Streptokinase