Autoimmune renal disease. Development of renal lesions and circulating antibodies in rats immunized with homologous kidney fractions.

Rats were immunized by one to eight intraperitoneal administrations of species-homologous kidney fractions (prepared according to Ryan's differential centrifugation technique) emulsified in Freund's complete adjuvant. Proliferative and membranous glomerulitis ensued in about one-third of animals receiving five or more injections of any of the four renal preparations, i.e. heavy particle, mitochondrial, microsomal and soluble fractions. A significant increase in the incidence and titre of complement-fixing antibodies to renal antigens occurred, beginning with the third injection in rats sensitized with the heavy particle material and soluble fraction, and possibly also with the microsomal fraction; the mitochondrial fraction was ineffective in this respect. In this as in previous studies, neither a positive nor a negative correlation was established between the development of renal disease and the formation of circulating antibodies, glomerulitis frequently being found in the absence of detectable antibodies and vice versa. It is hypothesized that immunization with renal antigens elicits an immune response in the wake of which two independent processes are observed, namely the development of renal disease and the formation of circulating antibodies.