IL4R and infection: Upon infection with L. major LV39, the parasite loads in the popliteal lymph nodes of global IL-4Rα−/− BALB/c mice appeared to be significantly higher than those of the littermate control IL-4Rα−/lox BALB/c mice, which has been observed previously (24), while parasite loads in the spleen were significantly lower, as anticipated (Fig. 2B).