In vitro treatment with interleukin-2 normalizes type-1 cytokine production by lymphocytes from elderly.

The term immunosenescence is taken to mean the deterioration of immune function seen in elderly, which is manifested in increased susceptibility to infectious diseases, neoplasias, and autoimmune diseases. It is only recently that we have begun to understand the cellular and molecular changes involved. Of special interest in this regard are observations of a decline in synthesis of Type-1 cytokines which predisposes to diminished cell mediated immunity. We have evaluated the production of type 1 cytokines in old and young donors either in presence or in absence of recombinant interleukin-2 (rIL-2). Lymphocytes were stimulated with plastic bound anti-CD3 and after 48 h the supernatants were harvested and stored at -70 degrees C until assay. Type 1 cytokine, i.e. IL-12 and interferon-gamma (IFN-gamma) production by anti-CD3 stimulated lymphocytes from old subjects was significantly reduced when compared to that from young ones. This impaired production was reversed by adding rIL-2 in the culture medium. In previous studies on aged subjects, we have been able to demonstrate that in vitro treatment with rIL-2 completely restores proliferative responses and partially rescues the increased apoptosis of T cell cultures. Present and previous results suggest that rIL-2 completely restores Type 1 responses by overcoming the well known costimulation deficit of aged lymphocytes.