Reduced eosinophilia and impaired worm expulsion in basophil-depleted mice. (A) 4get/rag^−/− mice were infected with N brasiliensis after they had been reconstituted with leukocytes from IL-4/IL-13^−/− mice, sensitized with serum from N brasiliensis–infected wild-type mice, and either depleted of basophils (▩) or not (□). The number of basophils and eosinophils was determined in the lung and spleen on day 10 after infection. Plots show combined results from 2 independent experiments with 6 mice per group total. *P < .01 by Mann-Whitney U test. (B) IL-3–induced basophilia does not cause eosinophilia. The graphs show the frequency of basophils (left) and eosinophils (right) among total peripheral blood leukocytes (PBLs) of normal 4get mice at indicated days after transfer of polyclonal T cells that had been transfected with IL-3 cDNA-encoding retroviruses. (C) Number of adult worms in the small intestine of 4get/rag^−/− mice that had been reconstituted with leukocytes from IL-4/IL-13^−/− mice, sensitized with serum from N brasiliensis–infected wild-type mice, and either depleted of basophils (▩) or not (□). The graph shows pooled results from 3 independent experiments with 8 to 9 mice per group total. **P = .021 by Mann-Whitney U test. For panels A and C, each dot presents 1 mouse. The horizontal bars show the statistical comparison.