Supplemental zinc restores antibody formation in cultures of aged spleen cells. III. Impairment of II-2-mediated responses.

The effects of zinc on interleukin-2(IL-2)-dependent T cell responses of lymphocytes from immunodepressed aged mice and from young adult animals were studied. Concentrations of zinc which have been shown to restore antibody formation in cells from aged mice and to increase the production of Il-1 and Il-4 inhibited the production of Il-2. Cells from both young adults and aged mice were inhibited similarly. Zinc also impaired the ability of aged T cells to proliferate in response to concanavalin A and exogenous Il-2, but enhanced the proliferation of similarly activated splenic cultures containing both T and B cells. Cultures of isolated B lymphocytes produced antibody to sheep red blood cells if the cells were provided with supplemental zinc and Il-1. In contrast, recombinant Il-2 with or without zinc did not activate antibody formation. The results support the premise that the restorative effects of zinc are independent of Il-2 and that Il-2 is not a necessary mediator for antibody production in the aged.