title: Modulation of human lymphocyte functions by group A streptococci.
abstract: Intact (heat-inactivated) bacteria and isolated cellular components of pathogenic group A (M type 5 or 12). B. C. and G streptococci were used to evaluate the in vitro reactivity of mononuclear cells (MNC) from peripheral blood of healthy donors and from human tonsils. High doses of A-streptococcal cells, cell walls, and cell membranes stimulated DNA synthesis, production of leukocyte migration inhibitory factor (LIF), and immunoglobulin (Ig) secretion in MNC from all donors. A streptrococci stimulated higher proliferation rates and larger numbers of plaque-forming cells (PFC) in tonsil cell cultures than in blood MNC cultures. Polyclonal activation of both tonsil and blood B lymphocytes by A-streptococcal cell components was T cell and monocyte dependent, thus showing a similarity between these structures and pokeweed mitogen (PWM), which is a polyclonal T-cell activator (PTA). Cocultivation studies demonstrated that, in the presence of A streptococci, precultured MNC and T cells can suppress the blastogenic and PFC responses of autologous fresh MNC stimulated by phytomitogen or antigen, which is very similar to the concanavalin A (Con A)-induced activation of suppressor cells. In contrast, similar group B-, C-, and G-streptococcal cell envelope biostructures failed to activate blood or tonsil lymphocytes to proliferate, differentiate, or produce LIF.
mesh_terms: D000328:Adult; D001770:Blood Bactericidal Activity; D006801:Humans; D007108:Immune Tolerance; D007231:Infant, Newborn; D007961:Leukocyte Migration-Inhibitory Factors / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D014066:Palatine Tonsil / Q000166:cytology; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000502:physiology
chemical_list: D007961:Leukocyte Migration-Inhibitory Factors