Autoimmunity as a cause of sensorineural hearing has yet to be completely confirmed or characterized. However, the evidence of antibody to inner-ear antigens in sera from patients with the clinical diagnosis of autoimmune sensorineural hearing loss (AISNHL) and experimental models strongly support this possibility. 4-2’In 1987, Harris6 demonstrated hearing loss and inner-ear lesions in guinea pigs immunized with bovine inner-ear extract. Subsequently, Orosco et al.* immunized mice and guinea pigs with chick and guinea pig inner-ear tissues and found that the animals developed transient hearing loss and serum antibodies to hair cell stereocilia. We followed these experiments with the development of monoclonal antibodies to inner-ear antigens by immunizing mice with chick and guinea pig inner-ear tis~ ue.~*~~~ We characterized two classes of monoclonal antibodies (MAb) to inner-ear antigens. One class (KHRI-5 and KHRI-6) stains~ tereocilia.~~ The other class is represented by MAb KHRI-3, which binds to inner ear supporting cells in a characteristic punctate “stacked wine glass” staining pattern. 22 It also identifies a 68-kD protein in Western blots of inner-ear extracts. 20

In vivo studies showed that mice carrying the KHRI-3 hybridoma develop highfrequency hearing loss. 2o The hearing loss is associated with high circulating KHRI-3 antibody titers and loss of outer hair cells in the basal turn of the cochlea, the region that encodes high-frequency sounds. More recent studies using in vivo infusion