FOXP3 and infection: Taken together, we showed that the early secretion of IL-10 by antigen-specific FoxP3− T cells suppresses the development of an inflammatory response following infection with L. major. Thus, IL-10 secretion by T cells is not only involved in the long-term control of infection and prevention of overwhelming immune activation, but also has a crucial effect on immune activation early after infection, influencing disease outcome and vaccine efficiency.