The endolymphatic sac: its importance in inner ear immune responses.

The present study investigated the role of the endolymphatic sac in the generation of inner ear immune responses. The inner ear immune response to KLH antigen challenge was examined in animals whose endolymphatic sac was surgically obliterated and in a sham operated control group. In primary inner ear immune responses, endolymphatic sac obliteration resulted in reduced serum anti-KLH levels, compared to controls, while no difference was observed for perilymph anti-KLH levels. In secondary inner ear immune responses, endolymphatic sac obliteration resulted in significantly suppressed perilymph anti-KLH levels and greatly reduced cellular infiltration within the cochlea. In contrast, the sham operated animals showed a greatly increased number of plasma cells and lymphocytes in the perisaccular space and the endolymphatic sac lumen. These findings suggested that the endolymphatic sac must play an integral role in the generation of both systemic and local antibody responses following inner ear antigen challenge. The endolymphatic sac, like the gut, appears to have an immunological as well as a resorptive role in the host.