Circulatory antigen of Heymann nephritis. III. Presence of the 70-kD circulatory protein in the immune deposits of Heymann nephritis.
An antigen of 70 kD size has been isolated previously from normal rat serum which has immunological cross-reactivity to the Heymann nephritis antigen, F x 1A. Its role in the pathogenesis of Heymann's nephritis was unknown. In this investigation we tested for the presence of 70-kD circulatory antigen in the glomerular immune deposits of Heymann's nephritis. Further, its presence was correlated with severity of disease. It was observed that the presence of the 70-kD antigen strongly correlated with the existence of electron-dense deposits in the lamina rara externa (LRE) of the glomerular capillary wall and with pathologic proteinuria. Temporally, the presence of the 70-kD antigen in the immune deposits was followed by large electron-dense deposits, enhanced complement activity and proteinuria. The data suggest that in the growing immune complex lattice in the LRE, the 70-kD circulatory antigen by virtue of its small size, mobility and antigen cross-reactivity facilitates cross linking and coalescence of immune complexes, resulting in electron-dense immune deposits (EDD) formation which initiates complement activation and consequent proteinuria.
Singh
A K
AK
Department of Medicine, Rush-Presbyterian-St Luke's Medical Center, Chicago, IL.
Schwartz
M M
MM
D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology; D005921:Glomerulonephritis / Q000276:immunology*; D026541:Heymann Nephritis Antigenic Complex; D008562:Membrane Glycoproteins / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification*; D011507:Proteinuria / Q000378:metabolism; D051381:Rats; D013997:Time Factors
D000936:Antigen-Antibody Complex; D026541:Heymann Nephritis Antigenic Complex; D008562:Membrane Glycoproteins