Interleukin-35 Limits Anti-Tumor Immunity (Immunity)

Interleukin-35 (IL-35) is a Treg-derived inhibitory cytokine that limits T cell proliferation. However, its impact on, and mechanism of action within, tumors is unknown. Vignali and colleagues show that Treg cell-derived IL-35 promotes tumorigenesis by contributing to T cell exhaustion and thereby limiting anti-tumor immunity.