C3d immunohistochemical staining in serial sections of paraffin-embedded tissue of MN-II. A. PAM-Masson stain. B. The same region with A, with high-pressure heating plus trypsin retrieval, C3d staining was strongly positive in capillary loop, no backgroud. C3d was also positive in the global sclerotic glomerulus. C. With high-pressure heating plus trypsin retrieval, primary antibody was replaced by PBS as negative control. D. With no antigen retrieval, C3d was faintly positive. E. The negative control with no antigen retrieval. F. With trypsin retrieval, C3d was weakly positive. G. The negative control with trypsin retrieval. H.With high-pressure heating retrieval, C3d was moderately positive. I. The negative control with high-pressure heating retrieval.