Ex vivo model of leukocyte migration into herpes simplex virus-infected mouse corneas

We are investigating neutrophilic infiltration into herpes simplex virus type 1 (HSV-1)-infected mouse corneas. Using a novel ex vivo corneal migration assay, we demonstrated two waves of neutrophil chemotaxis in HSV-1-infected corneas. An early chemotactic gradient developed within 48 h in concert with the appearance of HSV-1 epithelial lesions, peaked by 4 days post-infection (p.i.), and degraded by 6-8 days p.i.. A second chemotactic gradient appeared 10 days after infection, just before the initiation of chronic inflammation. The gradient was maintained in corneas that developed inflammation but rapidly degraded in corneas that failed to develop inflammation. The early chemotactic gradient was established in the absence of T lymphocytes, but the second chemotactic gradient was virtually abrogated by T cell depletion. We conclude that HSV-1 infection induces two temporally separated neutrophil chemotactic gradients in the mouse cornea: an early, transient, T cell-independent gradient; and a later, chronic, T cell-dependent gradient.