Deposition of IgG and C3 in glomeruli is a characteristic feature of kidney disease in MRL/lpr animals. To examine to what extent CRIg-Fc could block IgG and C3 deposition, we stained frozen kidney sections from CRIg-Fc and controltreated animals with appropriate antibodies. Large amounts of IgG deposition can be seen in the kidneys of controltreated mice, while in contrast, CRIg-Fc treatment significantly limited (p = 0.004) deposition of IgG (Figs. 3C/D). Given that serum levels of anti-dsDNA antibody did not change after CRIg-Fc treatment, it can be inferred that
inhibition of complement activation may be related to effective immune complex processing and clearance in the glomeruli. Similarly, staining of C3 in the kidney sections revealed greater deposition in the control-treated mice as compared to the CRIg-Fc-treated animals (p = 0.0002) (Figs. 3E/F).
Macrophage infiltration into the glomeruli during inflammation leads to renal damage. Macrophages can produce cytokines, as well as reactive oxygen and nitrogen intermediates that cause renal damage. Studies in lupus-prone mice