Purpose: The purpose of this study was to identify target antigens of autoimmune keratitis with a disease-prone mouse model.
Methods: BALB/c nude mice grafted with embryonic rat thymi (TG nude mice) develop various organ-localized autoimmune lesions, including keratitis. A hybridoma producing a monoclonal antibody (OT-20), specific for corneal epithelium was established by using spleen cells from this model mouse of keratitis, and the target of OT-20 was identified by immunoblot analysis. Then, using the antigen, T-cell proliferation and cytokine production by TG nude mice with keratitis were examined.
Results: Immunoblot analysis revealed alpha-internexin to be the target antigen of OT-20 that specifically recognizes corneal epithelium. Sera from TG nude mice with keratitis reacted with alpha-internexin on Western blot analysis, and the T cells of these mice on stimulation with alpha-internexin exhibited proliferation responses and produced IL-2, IFN-gamma, and TNF-alpha, but not IL-4 or IL-5.
Conclusions: These results suggest that alpha-internexin is one of the corneal antigens associated with keratitis, developing spontaneously in TG-nude mice, with a probable pathogenic role.