Production of endolymphatic hydrops induced by directly infused monoclonal antibody against type II collagen CB11 peptide

Autoimmune ear disease induced by type II collagen has been investigated by Yoo et al. In the present study, we investigated the effects of direct chronic infusion of type II collagen specific monoclonal antibodies into guinea pig cochlea. Type II collagen fragment CB11 peptide specific monoclonal antibodies (CB11 Mabs) were infused directly into the scala tympani of guinea pig using Alzet mini-osmotic pump (CB11 Mabs group). As a control, normal mouse serum was infused using the same method (control group). To evaluate the auditory function, brain stem auditory-evoked potentials (BAEPs) were recorded. In the CB11 Mabs group, 80% of the animals showed increased hearing threshold of more than 25 dB, 7 days after implant. This hearing threshold shift continued until the end of this study. The hearing threshold shift observed in guinea pigs of the control group was minimal (15 dB or less). To detect the structural changes, histopathologic studies were performed using hematoxylin and eosin staining. Inflammatory cell migration was detected mainly in the scala tympani of the guinea pigs of both groups. In CB11 Mabs group, endolymphatic hydrops and atrophic change of the organ of Corti were also observed. These results of this experiment suggest that type II collagen autoimmunity is responsible for the production of hearing loss and endolymphatic hydrops.