The cleaved/activated Caspase-1, cleaved/activated IL-1β, and IL-18 were significantly induced in human corneal epithelial cells following infection with virulent laboratory strains of HSV-1, McKrae and 17, as early as 2 h post-infection, compared to control β-actin (P < 0.05) (Figures 6A,B). Here, IL18 is linked to infection.