THE LOCALIZATION AND SPECIFICITY OF GUINEA-PIG INNER-EAR ANTIGENIC EPITOPES

In this study we investigated the relative localization of some antige nic epitopes in the inner ear. The inner ear protein antigens were ext racted from various parts of the guinea pig inner ear. Brain, kidney, lung, heart and liver extracts were also obtained. We found by SDS-pol yacrylamide gel electrophoresis that total inner ear extracts separate d into three high concentration polypeptide bands with molecular weigh ts of approximately 30, 42, 58 kd and three low density bands of 20, 2 5 and 35 kd. The 30 kd band was found mainly in the extract of the spi ral ganglion and the acoustic nerve in the modiolus. The 42 and 58 kd bands were detected in the extract of the spiral ligament and the stri a vascularis. The Organ of Corti and the basilar membrane extract gave rise to three bands of 30, 42 and 58 kd. Twenty-eight of the 75 sera from patients with inner ear disease reacted with the 30 and 58 kd ban ds of the inner ear protein extracts by immunoblotting. Sixteen of the se 28 positive sera were then used to probe immunoblots of the brain, kidney, lung, heart and liver extracts. The 58 kd band was also found in protein extracts of the brain, the lung and the liver. This study s uggests that the 30 kd antigenic epitope may be mainly related to the acoustic nerve and that the 58 kd antigenic epitope is not cochlear sp ecific.