Chronic antigen-antibody-complex glomerulonephritis in mice

Daily injection of human serum albumin into mice genetically selected to produce low-affinity antibody to protein antigens resulted in a more severe antigen-antibody-complex-induced glomerulonephritis than in mice producing high-affinity antibody. The low-affinity mice had higher levels of circulating antigen-antibody complexes, greater impairment of renal function and reduced reticuloendothelial clearance of 125I-PVP compared to high-affinity mice. Electron microscopy of glomeruli revealed the presence of subepithelial electron-dense deposits in low-affinity mice and predominantly subendothelial-mesangial deposits in high-affinity mice which corresponded to the predominantly capillary staining in low-affinity mice and mesangial staining in high-affinity mice by immunofluorescence. Auto-radiography of electron-microscopy sections demonstrated the presence of antigen in the electron-dense deposits, indicating that these deposits indeed contained antigen-antigen complexes.