In our pursuit to purify autoantigens and examine the presence of autoantigens in different organs, we investigated two extraction techniques to provide both water-soluble and SDS-soluble fractions of bovine inner ear, brain, kidney and liver. We have also examined the sera of patients with autoimmune sensorineural hearing loss for the presence of autoantibodies using Western blotting immunoassay against antigen extract of bovine inner ear, brain, kidney and liver. In immunoblots, all tissue extracts contain 68kD non-organ specific autoantigen. In addition to 68kD protein, inner ear includes 50kD and 33-35kD proteins, and brain includes 50kD, 37kD, 36kD and 35kD proteins, and kidney contains 50kD protein, and liver also contains 32kD protein. The results suggest that 68kD protein is a non-organ specific autoantigen. The SDS-soluble fractions are ideal for immunoassays in clinical study because the water-soluble fractions contain higher concentration of bovine serum albumin from blood contamination during tissue dessection.