Age-related impaired proliferation of peripheral blood mononuclear cells is associated with an increase in both IL-10 and IL-12.

Reflective of age-associated decline in immune function among elderly individuals is a decrease in in vitro T cell proliferative ability. Impaired T cell proliferation in the elderly may result from disruption of the well-balanced network of regulatory cytokines produced during an immune response. The purpose of this study was to identify age-related changes in the production of interleukin (IL)-10 and IL-12, and to determine whether in vitro T cell proliferation can be enhanced in the elderly by modulation of these two key cytokines. The superantigen Staphyloccocus entertoxin B (SEB) was used to stimulate proliferation and IL-10 and IL-12 production in peripheral blood mononuclear cells (PBMC) in vitro. Proliferation was determined by standard tritiated thymidine uptake. Cytokine levels in culture supernatants were measured by ELISA. We observed impaired SEB-induced proliferation of PBMC in the elderly that is comparable to that seen with the polyclonal mitogen Con A. This age-related decline in proliferation was associated with increased production of both IL-10 and IL-12. Modulation of PBMC proliferative response with either recombinant IL-12 or IL-10-neutralizing antibodies can boost proliferation of elderly PBMC to the levels seen in unmodulated young controls.