IL4 and infection: There was a more striking reduction in P. murina infection in IL4Rα−/− pups at 5 and 6 weeks post-infection than in the IL-4−/− pups which corresponded to significantly increased P. murina-specfic serum IgG confirming that both IL-4 and IL-13 dampen the immune response to P. murina resulting in a prolonged clearance kinetics.