Figure 1.

T. gondii infection in C57BL/6 mice. (A) In intact animals, IFN-γ–producing Th1 cells efficiently control the infection. Some of these Th1 cells also produce IL-10, which helps limit the Th1 response and limit inflammation. (B) Blocking IFN-γ or IL-12 allows the infection to proceed unchecked, causing the rapid death of the animals. (C) Blocking the production of IL-10 by Th1 cells triggers an overproduction of proinflammatory cytokines by T cells and innate cells, resulting in the death of the infected animals, despite parasite clearance.