Gpr44−/− mice had slightly lower though not statistically significant infection-induced Il13 expression (Fig. 1 f) and IL-13 protein levels (Fig. S1 h) in the small intestine compared with WT mice at day 7 p.i. Thus, the immune response in Gpr44−/− mice was largely intact, yet they unexpectedly demonstrated enhanced clearance of N. brasiliensis. This evidence concerns the gene PTGDR2 and infection.