The histological localization and biochemical properties of the autoantigens relevant to experimental autoimmune ophthalmitis and thyroiditis were studied using sera from mice hyperimmunized with the corresponding tissue extract of syngeneic mice and Klebsiella O3 lipopolysaccharide (KO3 LPS) as a potent adjuvant. Specific antigens were detected in the lens of the eyeball by immunofluorescence test with sera from mice in which ophthalmitis had been induced and the antigens were lenticular proteins with molecular weights (MW) of 15, 000 (15K) to 25K, and 45K. The lenticular proteins with MW of 15K to 25K correspond to the subunits of crystalline. These findings clearly demonstrated that our experimental model for autoimmune ophthalmitis was classified as the lens-induced uveitis. The colloids of the thyroid follicles and the follicular cells were markedly stained by sera from mice in which thyroiditis had been induced. One of the autoantigens detected in the thyroid gland was biochemically consistent with a thyroglobulin subunit. It was also shown that these autoantigens detected in the present study were organ-specific but not species-specific. The nature of autoantigens in the eye and the thyroid gland is discussed.