Human interleukin-2 promotes proliferation of activated B cells via surface receptors similar to those of activated T cells.
Human interleukin-2 (IL-2) is a glycoprotein of relative molecular mass (Mr) 15,000, which is released by T lymphocytes on stimulation with antigen or mitogen and functions as a T-cell growth factor (TCGF) by inducing proliferation of activated T cells. It is generally accepted that resting or activated B cells do not respond directly to IL-2 but require for their proliferation other T-cell-derived lymphokines usually referred to as B-cell growth factors (BCGFs). Recently, however, a monoclonal antibody reacting with the IL-2 receptor molecules expressed by activated T cells (anti-Tac) was shown to react also with certain B tumour cells; in addition, murine B cells proliferate in response to pure human IL-2. We now show that recombinant IL-2, derived from Escherichia coli expressing the human gene, is able to promote strong proliferation of human B cells activated with protein-A-rich Staphylococcus aureus Cowans strain I. Moreover, we demonstrate that the anti-Tac antibody also reacts with S. aureus-activated normal B cells and inhibits sharply the proliferative response of such cells to IL-2. Finally, immunoprecipitation experiments reveal that anti-Tac defines similar molecules on activated T and B cells.
D000818:Animals; D000936:Antigen-Antibody Complex; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007106:Immune Sera; D007376:Interleukin-2 / Q000276:immunology* / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D011971:Receptors, Immunologic / Q000276:immunology*; D015375:Receptors, Interleukin-2; D013154:Spleen / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000936:Antigen-Antibody Complex; D007106:Immune Sera; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2