title: Suppression of antibody response by group A streptococcal pyrogenic exotoxin and characterization of the cells involved.
abstract: The effect of purified streptococcal pyrogenic exotoxins (SPE) on the antibody response to sheep erythrocytes was studied in cultures of mouse spleen cells. Purified SPE types A, B, and C shared the ability to suppress the day 4 direct plaque-forming cell response when added to cultures. SPE A and C were most suppressive at concentrations of 0.1 to 1 ng per culture, while SPE B was active at 1 microgram per culture. Pretreatment of mice with SPE A, 3 h before removal of their spleens for culture, also produced suppression. Cell populations were separated from spleens of normal and toxin-treated mice and recombined in culture to test the cellular site of action of SPE immunosuppression. When nonadherent cells (lymphocytes) and adherent cells (macrophages) from control and SPE-treated mice were separated and recombined, the plaque-forming cell response depended on the source of lymphocytes. Macrophages from toxin-treated mice functioned normally in the presence of control lymphocytes. In a further experiment, toxin pretreatment failed to suppress the plaque-forming cell response of spleen cells that were T-cell depleted and reconstituted with control thymocytes. When the T lymphocytes were removed from toxin-treated spleen cell suspensions, the remaining cells were able to respond normally to antigen if normal helper T cells were provided. The results suggest that the suppressive activity of SPE on antibody production is mediated by altered activity of T lymphocytes.
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D001402:B-Lymphocytes / Q000276:immunology; D001427:Bacterial Toxins / Q000494:pharmacology*; D046508:Culture Techniques; D005098:Exotoxins / Q000494:pharmacology*; D007075:Immunoglobulin M / Q000096:biosynthesis; D007165:Immunosuppression Therapy; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011749:Pyrogens / Q000494:pharmacology*; D013154:Spleen; D013297:Streptococcus pyogenes; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; D007075:Immunoglobulin M; D011749:Pyrogens