Role of NK cells and TGF-beta in the regulation of T-cell-dependent antibody production in health and autoimmune disease

Natural killer (NK) cells are a third lymphocyte population especially impo rtant in innate immunity. NK cells may also have an important role in the r egulation of acquired immunity. These lymphocytes spontaneously produce lar ge amounts of both active and latent transforming growth factor-beta (TGF-b eta). NK-cell-derived TGF-beta 1 enabled activated CD8(+) T cells to inhibi t antibody production by blocking the induction of this response. Productio n of lymphocyte-derived TGF-beta is decreased in systemic lupus erythematos us. Insufficient levels of this cytokine in SLE and other autoimmune diseas es may contribute to defective T regulatory cell function characteristic of this and other autoimmune diseases. NK cells are found in mucosal tissues and the TGF-beta spontaneously released by these cells could contribute to the usual tolerogenic response of T cells to antigens presented at these si tes. Thus, in addition to its well known immunosuppressive effects, TGF-bet a could have an equally important role in the generation of regulatory T ce lls. (C) 1999 Editions scientifiques et medicales Elsevier.