Since IL-4 is associated with driving the transition of macrophages to an alternative activation phenotype, we examined Ym1 expression on CD11c+CD11b− AMs and found that the number of Ym1+ cells was similar between IL-4−/− and wild type pups however the MFI peaked at day 21 post-infection in IL-4−/− pups compared to a peak at day 30 post-infection in wildtype pups (Figure 4G,H). This evidence concerns the gene ITGAM and infection.