Cutting edge: IL-10-producing CD4(+) T cells mediate tumor rejection

IL-10 has potent immunosuppressive properties, and IL-10-producing CD4(+) Tr1 cells have been characterized as regulators of Th1-mediated immunity. In this study, using a s.c. model of glioma cell growth in mice, we demonstrate that CD4(+), but not CD8(+), T cells play a critical role in tumor rejection following vaccination with irradiated glioma cells. Surprisingly, glioma-specific CD4(+) T cells produce IL-10 but neither IL-4 nor IFN-gamma, and glioma rejection is compromised in IL-10(-/-) hosts. Hence, our findings demonstrate that IL-10-producing CD4(+) T cells can manifest antitumor functions and suggest that IL-10 may have proinflammatory effects in disease states.