TYK2 and infection: Since Tyk2-deficient mice produced high level of IFN (Fig. 2), we studied the IFN responses by IFN-inducible poly I:C treatment, coxsackie B4 virus, which belongs to a picorna virus group as well as EMC-D virus, infection, and herpes simplex virus (HSV), as a representative enveloped DNA virus, infection in various genotypes of mice, such as B6, SJL and Tyk2-mutated/B6.