Figure 2.

Compatibility of Sirius red counterstain following immunodetection is dependent on antigen retrieval methods. (A) After full heat-induced antigen retrieval (HIAR) for immunolabelling of wide-spectrum keratin (CK-WSS; brown), Sirius red staining displayed widespread non-specific background and nuclear staining (Inset: higher magnification (×460) with arrow indicating positive hepatocyte nuclei). In other regions, collagen fibers appeared globular with a distinct loss of delicate fibrous spurs (B). Optimized immunohistochemical staining for CK-WSS and F4/80 (brown) with Sirius red counterstain utilizing reduced HIAR (C) or trypsin digest (D), respectively. Scale, 100 µm; Inset in (A), 20 µm.