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

In various patterns of sensorineural hearing loss including Meniere's disea se, which may show improvement in auditory function following immunosuppres sive therapy, an isolated autoimmune disease of the inner ear has been post ulated. Because of the lack of well-defined diagnostic criteria to identify autoimmune processes within the inner ear and the fact that the human inne r ear is one of the few organs of the body not amenable to diagnostic biops y, there has been great interest in developing animal models that mimic the se clinical entities. Previous studies have found evidence that this proces s might be cell mediated and that the endolymphatic sac functions as an imm unodefensive organ for the inner ear. By heterologous immunization of inbre d Lewis rats with inner ear tissue, an autoreactive inner-ear-specific T he lper cell line was established. After passive transfer of these cells a lab yrinthitis was induced in recipient animals. Immunohistochemically, T helpe r cells were first identified in the cochlea suggesting that this cell type might carry the autoantigenic epitope. Autoantibodies against inner ear ti ssue were demonstrated in animals with histologically evident labyrinthitis . We conclude that this experimental design can serve as an animal model fo r cell-mediated autoimmune disease of the inner ear and could be used to ex plain the etiology of certain types of sensorineural hearing loss such as M eniere's disease. With this approach the identification of the causative au toantigen should be possible and will lead to the development of appropriat e clinical tests to diagnose autoimmune diseases of the inner ear in humans .