Phenotypic changes and inflammatory cell distribution in the cornea during development of experimental immune-mediated blepharoconjunctivitis.

PURPOSE: To investigate the morphological changes in the cornea during the development of experimental immune-mediated blepharoconjunctivitis (EC).

METHODS

EC was induced in Brown Norway (BN) rats by active immunization with ovalbumin (OVA) emulsified in complete Freund's adjuvant and a subsequent challenge by OVA eyedrops. The corneas were analyzed immunohistochemically.

RESULTS

Before the induction of EC, cells stained with OX6 (rat MHC class 2, RT1B), ED1 (tissue macrophages), ED2 (resident macrophages), CD4, or major basic protein were present in the peripheral corneal stroma. ED1- and OX6-stained cells were also observed in the central corneal stroma, and their number increased after the antigen challenge. Infiltration of cells stained with ED1, ED2, OX62 (dendritic cells), CD4, or CD3 (T cells) from the limbus to the peripheral corneal stroma started 6 h after the antigen challenge. Expression of MHC class 2 molecules was induced on the corneal epithelium by the antigen challenge.

CONCLUSIONS

The present study demonstrates for the first time the phenotypic changes and distribution of inflammatory cells in the cornea during the development of EC.