IL-4–independent and contact-dependent suppression of IFNγ production by basophil coculture. (A) OT-II CD4 T cells were stimulated in the presence of different numbers of basophils (none, 800, 4000, 20 000, or 100 000) obtained from the liver of IL-3–treated IL-4–deficient G4/G4 mice. The ratios of T cells and basophils are indicated on the x-axis. Cytokine production was determined after 3 days of culture. The graph shows the average percentages ± SD of relative cytokine-producing CD4 T cells from 2 independent experiments. (B) Basophils isolated from either wild-type (left panel) or IL-4–deficient G4/G4 (right panel) mice were added either together (CC) or separated (TW) in Transwell. Shown are the average percentages ± SD of relative proportions of IFNγ–producing cells measured by intracellular staining from 3 independent experiments.