CD4 and infection: Given the critical role of TRIM29 in IL-18 production in IECs both in vitro and in vivo during infection of enteric RNA viruses including EMCV and rotavirus, we next investigated whether the increased IL-18 in IECs from Trim29IEC-KO mice augments the recruitment of intraepithelial Ly6A+CCR9+CD4+ T cells in small intestines during enteric RNA virus infection in vivo.