Immune complex glomerulonephritis in mice infected with Escherichia coli.

Abstract

C57Bl/6 mice were injected intraperitoneally with 10(8) to 2 x 10(8) living K 38 Escherichia coli (E. coli) and serological changes and kidney involvement were studied. E. coli were found in the blood 45 min to 24 hr after injection. In serum, large amounts of deoxyribonucleic acid (DNA) were present 24 hr after E. coli injection, and thereafter disappeared. Seven days after infection, antibodies directed against E. coli, anti-DNA antibodies and C1q-binding substances were found in serum and the kinetics of the variations of these parameters were studied until day 35. Kidney lesions were evaluated immunochemically and by optical and electron microscopy. In the glomeruli, heavy granular deposits of IgG and IgM were constantly found in mesangium and along capillary walls. In most kidneys slight granular deposits of IgG and IgM were also found in the tubules. Histological studies revealed in the glomeruli mild endocapillary cell proliferation, focal thickening of glomerular basement membrane and dense deposits in mesangial and subendothelial areas and inside the glomerular basement membrane; in the tubules dense deposits were focally observed inside the tubular basement membrane.