Different patterns of sensorineural hearing loss with a potential improvement in auditory function following immunosuppressive therapy might be caused by an isolated autoimmune disease of the inner ear. Because of the lack of well-defined detection methods 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. Previous studies found evidence that this entity might be cellular mediated. By heterologeous immunization of inbred Lewis rats with inner-ear tissue, an autoreactive inner-ear-specific T-cell line was established. After passive transfer of these cells, a labyrinthitis was induced in recipient animals. The experimental design can serve as an animal model for a cellular-mediated autoimmune disease of the inner ear. Further studies have to split the cochlear proteins and to identify the protein with the strongest autoimmunological potency. After biotechnical production of this protein, a clinical test to diagnose an autoimmune disease of the inner ear in man should be possible.