Analysis of the Autoantigen using the Autoimmune Keratitis Spontaneity Mouse Model

Abstract

Abstract: : Purpose: Nude mice acquire their immune function by grafting the xenogeneic thymic rudiments (TG nude mice). However, multiple organ-localized autoimmune diseases such as keratitis and uveoretinitis developed spontaneously in TG nude mice. In this paper, we analyzed the autoantigen of autoimmune keratitis using this mouse model. Methods: Fifteen-day-old F344 embryonic rat thymi were transplanted under renal capsule of 4-week-old BALB/c nude mice (TG nude mice). Using spleen cells of the TG nude mouse with autoimmune keratitis, we established a hybridoma that produced a monoclonal antibody, which peculiarly reacts with the corneal epithelia. The target molecule of this monoclonal antibody is examined for the intermediate filaments by immunoblotting. It was also examined whether the autoantibody that reacts with the same molecule also existed in the blood of the TG nude mice. Results: The monoclonal antibody produced by the established hybridoma was peculiarly reacted with cornea epithelia. Then, it became clear that this monoclonal antibody recognized one of the intermediate filaments. The protein was the alpha-internexin with 66Kd. In the blood of TG nude mice with keratitis, the autoantibody that reacts with the alpha-internexin was also detected. Conclusion: Mooren's ulcer is known as human aseptic keratitis and cause severe ulceration in peripheral cornea. Recently, it is considered that the autoimmunity is a cause of this disease, but the pathogenesis remains poorly understood. The pathological characteristics of keratitis developed in TG nude mice is quite similar as that of Mooren's ulcer. So far as we know, this animal model is the first to demonstrate autoimmune keratitis spontaneously. TG nude mice will be extremely useful to elucidate the etiology of human autoimmune keratitis such as Mooren's ulcer.

Keywords: autoimmune disease • keratitis • animal model