Reconstitution of in vivo cell-mediated lympholysis responses in aged mice with interleukin 2

Advancing age is accompanied by declining immune potential. Both humoral and cellular immune responses are diminished in aged humans and experimental animals. A major lesion preventing effective T cell-mediated responses is the lack of interleukin 2 (IL 2) synthesis in aged mice. Addition of IL 2 can effectively reconstitute in vitro T cell-dependent humoral and cell-mediated immunity. These results have been extended, demonstrating that IL 2-containing lymphokine preparations when administered with antigen can restore the ability of aged mice to generate cytotoxic T lymphocytes in vivo. Furthermore, IL 2 has been identified as the active component of these lymphokine preparations through the use of purified human IL 2 prepared by recombinant DNA and gene cloning technology. The cloned IL 2 is highly effective in enhancing the immune responses of aged animals both in vitro and in vivo.