Antibodies to species homologous tissue antigens in the rat. II. Circulating antibodies during the development of autoimmune renal disease.

Rats were immunized with species-homologous organ homogenates emulsified in Freund's complete adjuvant. Sensitization with kidney and spleen homogenates stimulated in many but not in all animals the formation of circulating antibodies reacting in the complement fixation test with renal and splenic antigens. The observed immune response was probably not consequent on renal tissue damage per se, since it was absent in pyelonephritic rats. On the other hand, in many animals with chronic Masugi's nephritis circulating anti-kidney antibodies were observed. It can be assumed that the increase in incidence and titre of circulating antibodies following homoimmunization reflects an enhanced formation of naturally occurring anti-tissue antibodies.