Finally and despite the drastic suppression of intestinal IL-13 mRNA expression in IL-9R-deficient mice, the initiation of type 2 response to S. ratti infection as such was not defective as IL-4 and Arginase transcription increased during infection in WT and IL-9R−/− mice on BALB/c and C57BL/6 background. This evidence concerns the gene IL9R and infection.