IL-21 enhances and sustains CD8+ T cell responses to achieve durable tumor immunity: comparative evaluation of IL-2, IL-15, and IL-21.

Cytokines that use the common receptor gamma-chain for regulating CD8(+) T cell responses to Ag include IL-2, IL-15, and the recently identified IL-21. The ability of these cytokines to regulate antitumor activity in mice has generated considerable interest in understanding their mode of action. In this study we compare the abilities of IL-2, IL-15, and IL-21 to stimulate immunity against tumors in a syngeneic thymoma model.