title: A restricted component of T cell help in pokeweed mitogen-stimulated humans peripheral blood cell cultures.
abstract: Limiting dilution analyses using human T and B cells from the peripheral blood of individuals recently (2 to 5 weeks) boosted with tetanus toxoid or a combination of diphtheria and tetanus toxoids were performed in order to investigate the specificity of T cell help during in vitro pokeweed mitogen (PWM) stimulation. Limiting numbers of irradiated T cells were added to an excess of B cells and their ability to help 1) IgG anti-tetanus toxoid antibody or 2) IgG anti-tetanus toxoid and IgG antidiphtheria toxoid antibody production were compared. The helper activity for anti-tetanus toxoid antibody production did not dilute out at the same point as help for total IgG production. Cultures were observed at limiting dilutions of added helper T cells that produced anti-tetanus toxoid IgG or anti-diphtheria toxoid IgG but not both even though a sufficient number of potential specific IgG-producing B cells were present. A distribution analysis of the IgG anti-tetanus and IgG anti-diphtheria helper T cells indicated that the two subpopulations did not segregate together. Thus in the presence of PWM, individual helper T cells appeared capable of supplying help for a restricted number of B cells.
mesh_terms: D000907:Antibodies, Bacterial; D001402:B-Lymphocytes / Q000276:immunology; D002450:Cell Communication; D002478:Cells, Cultured; D004168:Diphtheria Toxoid / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D004168:Diphtheria Toxoid; D007074:Immunoglobulin G; D011043:Pokeweed Mitogens; D013745:Tetanus Toxoid