The distribution and molecular presentation of the brush border antigen of Heymann nephritis in various rat tissues.

A monospecific antiserum to gp600, a recently isolated and characterized antigen of Heymann nephritis (HN), was used in radioimmunoassay to measure the specific activity of the antigen in various rat tissues. Lung contained the highest amount followed by pancreas, stomach, small intestine, kidney, large intestine, seminal vesicle, epididymis, muscle, heart, brain, spleen, liver, testis and serum. Immunoprecipitation of the antigen with anti-gp600 and analyses of the precipitates on SDS-PAGE revealed that the majority of the tissues contained a cross-reactive 90 kD polypeptide antigen. Four of these tissues also contained a 66kD polypeptide antigen. Seminal vesicles, brain, kidney and liver contained a high mol. wt (greater than 330kD) antigen. Kidney possessed a unique set of antigens, namely 330kD, 110kD and triplet of 80kD besides the common 90kD and greater than 330kD antigens. These results show that antigens cross-reactive with HN gp600 antigen are present in other tissues but the biochemical nature of the kidney antigen is unique in comparison to antigen present in other tissues.