Immunofluorescence analysis of cytokeratin and vimentin in stromal fibroblasts and Hep-2 cell line. (A and D) Absence of immunoreactivity in sections incubated with control nonimmune mouse serum. Stromal fibroblasts (B and E) and Hep-2 cell line (C and F) were positive for vimentin and cytokeratin, respectively. (G): Densitometric analysis of immunofluorescence reaction to vimentin and cytokeratin in stromal fibroblasts and Hep-2 cell line. Scale bar, 20 μm.