title: Polyclonal activation of human lymphocytes in vitro-II. Reappraisal of T and B cell-specific mitogens.
abstract: The capacity of the T cell mitogens phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and Staphylococcus protein A (SpA) to induce B cell proliferation and differentiation was compared with the B cell mitogen, formalinized Staphylococcus aureus (STA). Lymphocyte subpopulations from normal donors and patients with various immunodeficiency diseases were studied. In the presence of the T cell mitogens, irradiated T cells were capable of providing a helper cell activity that enabled co-cultured B lymphocytes to proliferate in response to these mitogens and to differentiate into IgM-secreting (direct) hemolytic plaque-forming cells (PFC). In the PFC response, radioresistant T-helper and radiosensitive T-suppressor cell activities could be demonstrated. T-suppressor cell activity outweighed helper activity only in nonirradiated co-cultures stimulated with Con A. Patients with severe combined immunodeficiency lacked mitogen-induced helper T cells, whereas patients with various forms of humoral immune deficiency were normal in this respect. These findings and the tissue distribution of the helper activity is aquired early in post-thymic T cell differentiation. The data suggest that experiments with cell lineage-specific lymphocyte mitogens should be considered in the context of more complex cell-cell interactions.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D006462:Hemolytic Plaque Technique; D006801:Humans; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008433:Mathematics; D008934:Mitogens / Q000494:pharmacology*; D014066:Palatine Tonsil / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013897:Thoracic Duct / Q000276:immunology
chemical_list: D008934:Mitogens