IRF1 and infection: To investigate the potentially differential host responses to infection from our UL88-deficient viruses, we infected MRC-5 fibroblasts with WT TB40/E or UL88-STOP virus at an MOI of 0.05, then examined the protein levels of an array of innate immune signaling molecules including MyD88, IRF3, JAK1, STAT1, and IRF1, at day 15 post-infection.