Type II Collagen-Induced Autoimmune Ear Disease in Mice: A Preliminary Report on an Epitope of the Type II Collagen Molecule that Induced Inner Ear Lesions
To identify the epitope on the type II collagen molecule that induced autoimmune ear disease, electrophysiological and histological studies were carried out in DBA/IJ mice immunized with native chick type II collagen (CIIn) and cyanogen bromide (CNBr) peptide 11 (CB-11 peptide) that was cleaved from chicken type II collagen with CNBr digestion. Four months after immunization, three of six CIIn-immunized mice and five of six CB-11 peptide-immunized mice developed moderate hearing loss. No control animals showed hearing loss. The pattern of hearing loss was characteristic of progressive deafness. Furthermore, the immunized mice showed temporal lesions involving atrophy of the Corti organ and degeneration of the spiral ganglion, in proportion to the level of the hearing loss. Because similar inner ear lesions were induced by immunization with CIIn and CB-11 peptide, CB-11 peptide contains at least one epitope that induces autoimmune inner ear disease in collagen II-induced disease on the chick type II collagen molecule involved in pathogenesis of autoimmune ear disease. CB-11 peptides were concluded to contain the epitope that induces autoimmune inner ear disease in collagen IIn-induced disease.