IL4 and infection: In each of the models, CD4+ T cells are recruited to the site of inflammation, and each type of infection is dominated by the corresponding TH cell subset, in numbers and proportions; Influenza by TH1 cells (IFNγ), N. brasiliensis by TH2 cells (IL-4, IL-13), and A. fumigatus by TH17 cells (IL-17).