A rat T-cell line that mediates autoimmune disease of the inner ear in the Lewis rat

In various patterns of sensorineural hearing loss including Meniere's disease, which may show improvement in auditory function following immunosuppressive therapy, an isolated autoimmune disease of the inner ear has been postulated. Because of the lack of well-defined diagnostic criteria to identify autoimmune processes within the inner ear and the fact that the human inner ear is one of the few organs of the body not amenable to diagnostic biopsy, there has been great interest in developing animal models that mimic these clinical entities. Previous studies have found evidence that this process might be cell mediated and that the endolymphatic sac functions as an immunodefensive organ for the inner ear. By heterologous immunization of inbred Lewis rats with inner ear tissue, an autoreactive inner-ear-specific T helper cell line was established. After passive transfer of these cells a labyrinthitis was induced in recipient animals. Immunohistochemically, T helper cells were first identified in the cochlea suggesting that this cell type might carry the autoantigenic epitope. Autoantibodies against inner ear tissue were demonstrated in animals with histologically evident labyrinthitis. We conclude that this experimental design can serve as an animal model for cell-mediated autoimmune disease of the inner ear and could be used to explain the etiology of certain types of sensorineural hearing loss such as Meniere's disease. With this approach the identification of the causative autoantigen should be possible and will lead to the development of appropriate clinical tests to diagnose autoimmune diseases of the inner ear in humans.