IFITM proteins drive type 2 T helper cell differentiation and exacerbate allergic airway inflammation

The interferon‐inducible transmembrane ( Ifitm / Fragilis ) genes encode homologous proteins that are induced by IFNs. Here, we show that IFITM proteins regulate murine CD4 + Th cell differentiation. Ifitm2 and Ifitm3 are expressed in wild‐type (WT) CD4 + T cells. On activation, Ifitm3 was downregulated and Ifitm2 was upregulated. Resting Ifitm ‐family‐deficient CD4 + T cells had higher expression of Th1‐associated genes than WT and purified...