Exacerbation of corneal scarring in HSV-1 gK-immunized mice correlates with elevation of CD8+CD25+ T cells in corneas of ocularly infected mice

We have shown previously that exacerbation of corneal scarring (CS) in HSV-1 glycoprotein K (gK) immunized mice was associated with CD8(+) T cells. In this study, we investigated the type and the nature of the immune responses that are involved in the exacerbation of CS in gK-immunized animals. BALB/c mice were vaccinated with baculovirus expressed gK, gD, or mock-immunized. Twenty-one days after the third immunization, mice were ocularly infected with 2 x 10(5) PFU/eye of virulent HSV-1 strain McKrae. Infiltration of the cornea by CD4(+), CD8(+), CD25(+), CD4(+)CD25(+),CD8(+)CD25(+), CD19(+), CD40(+), CD40L(+), CD62L(+), CD95(+), B7-1(+), B7-2(+), MHC-I+, and MHC-II+, cells was monitored by immunohistochemistry, qRT-PCR and FACS at various times post-infection (PI). This study demonstrated for the first time that the presence of CD8(+)CD25(+) T cells in the cornea is correlated with exacerbation of CS in the gK-immunized group. (C) 2009 Elsevier Inc. All rights reserved.