Cell characterization: cytokeratin, E-cadherin, p120. A, B. In control SMGs (A), cytokeratin is immunodetected in branching epithelia and not in mesenchyme; with mCMV infection (B), cytokeratin is detected in the abnormal epithelia, in lumen-filling cells (double black arrowheads), and in the cytoplasm of stromal cells (black arrows) adjacent to pseudostratified epithelia. C, D. In control SMGs (C), E-cadherin is localized solely to epithelial cell membranes. In mCMV infected SMGs (D), a decrease in E-cadherin immunostain is seen in epithelial cells facing the lumina (double white arrows) and in pseudostratified epithelia facing the stroma (double white arrowheads); E-cadherin is also localized to membranes of lumina-filling cells (white arrowhead) and to the cytoplasm of some metaplastic stromal cells (white arrow) adjacent to abnormal epithelia. E, F. p120 localization. In control SMGs (E), p120 is detected adjacent to epithelial plasma membranes and is absent from mesenchyme. With mCMV infection (F), p120 is seen in all epithelia, as well as in cells emigrating from ductal epithelia to stroma (double black arrow) and lumen-filling cells (black arrows). C, D were counterstained with DAPI. * lumen-filling cells. Bar: A, B, E, F: 20 μm; C, D: 27 μm.