Immunofluorescence of stromal cells from hematopoietic fetal liver.

(A) A 14-gw human fetal liver; (B) 14.5-dpc murine fetal liver; (C) AFT024 cell line from 14-dpc liver; and (D) 2018 cell line from 14-dpc liver. Fetal liver cells were obtained and cultured for 10 days in long-term culture medium; cells were then fixed and double-immunostained with Cy3-conjugated mouse anti-ASMA (red) and mouse anti–CK-8 (green; fluorescent secondary antibody was fluorescein isothiocyanate [FITC]–conjugated goat antimouse immunoglobulin). Panels show an overlay of the fluorescence signal from the 2 channels (red and green) to visualize a coexpression of the epithelial and mesenchymal marker. Expression of ASMA in cell lines is so intense that the signal appears yellow instead of red. Scale bar = 10 μm.