Studies in TLR9-knockout (KO) or IFN-α R-KO mice have demonstrated the critical role of these molecules for the induction of CXCL9 and CXCL10, the downstream recruitment of T cells and neutrophils in the cornea, and the control of viral shedding, highlighting the importance of IFN production in HSV keratitis (Conrady et al., 2011). This evidence concerns the gene IFNA1 and herpes simplex virus keratitis.