Involvement of CD8+ T-cells in exacerbation of corneal scarring in mice

Purpose. To determine the specific immune responses involved in the exacerbation of corneal scarring induced by HSV-1 in gK vaccinated mice. Materials and methods. BALB/c mice were vaccinated with HSV-1 glycoprotein K (gK) and ocularly challenged with HSV-1. Infiltration into the cornea of T cells and macrophages was monitored by immunocytochemistry, and the effect of depletion of CD4(+) T-cells, CD8(+) T-cells, or macrophages on corneal scarring was determined. Results. Following ocular challenge, CD4(+) and CD8(+) T-cells and macrophages were more abundant in the corneas of gK-vaccinated mice than in the corneas of mock vaccinated mice. Depletion of CD8(+) T-cells, but not of CD4(+) T-cells or macrophages, reduced the severity of corneal scarring in gK-vaccinated mice. Conclusions. We have shown that gK vaccination causes an overall increase in T cells and macrophages in the cornea after ocular HSV-1 challenge. The immunopathology induced by gK vaccination appears to be related to CD8(+) T-cell activity as depletion of these cells, but not other immune cells, reduced corneal scarring.