Immunoglobulin production in cultures of pokeweed mitogen stimulated human peripheral blood mononuclear cells requires interaction of interleukin 2 with the B cells.
Immunoglobulin (Ig) production in cultures of pokeweed mitogen (PWM)-stimulated human peripheral blood mononuclear cells (PBMC) is dependent on the presence of T cells. The latter can be replaced by a crude supernatant of PWM-stimulated PBMC, a conditioned medium containing interleukin 2 (IL-2) and presumably other helper factors for B cells. The present study examines the role of IL-2 among these helper factors. Anti-Tac, a monoclonal antibody that blocks the human IL-2 receptor, was found to suppress PWM-induced Ig production in cultures of human PBMC. The inhibition by anti-Tac was at least partly exerted at the level of B cells. Indeed, Ig production in cultures of T-cell-depleted PBMC or highly enriched B-cell preparations supplemented with PWM-induced conditioned medium was also inhibited by anti-Tac (82 +/- 13% inhibition of IgG and 83 +/- 12% inhibition of IgM production). When IL-2 was removed from the PWM-induced conditioned medium by absorption with an IL-2-dependent murine cytotoxic T-cell line, CTLL, the conditioned medium was unable to support PWM-induced Ig production by T-cell-depleted PBMC. On the other hand, recombinant IL-2 alone at a concentration similar to that of IL-2 in the PWM-induced conditioned medium was not able to support Ig production by PWM-stimulated B cells. We conclude that IL-2 acts on PWM-activated B cells in conjunction with other helper factors to induce Ig production and that anti-Tac inhibits PWM-induced Ig production by blocking IL-2 receptors on activated B cells.
D000328:Adult; D000911:Antibodies, Monoclonal / Q000502:physiology; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D001667:Binding, Competitive; D002469:Cell Separation; D003470:Culture Media; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D007376:Interleukin-2 / Q000502:physiology*; D015847:Interleukin-4; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000502:physiology; D008875:Middle Aged; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D003470:Culture Media; D006133:Growth Substances; D007136:Immunoglobulins; D007376:Interleukin-2; D008222:Lymphokines; D011043:Pokeweed Mitogens; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D015847:Interleukin-4