Enhanced viral immunoinflammatory lesions in mice lacking IL-23 responses

Herpes simplex virus (HSV) infection of the cornea culminates in an immunopathological lesion (stromal keratitis - SK) that impairs vision. This report shows that HSV infection results in IL-23 up-regulation, but if this response fails to occur, as was noted in p19-/- mice, the severity of lesions, their incidence and the level of viral induced angiogenesis were significantly increased compared to wild-type (WT) animals (p < 0.05). The higher disease severity in p19-/- mice appeared to be the consequence of an increased IL-12 response that in turn led to the induction of higher numbers of IFN-γ producing CD4⁺T cells, the principal orchestrators of SK. Our results indicate that the severity of HSV induced immunopathological lesions may be mainly the consequence of IL-12 driven Th1 T cell reactions rather than the action of IL-17 producing cells controlled by IL-23.