To further investigate the differences between uninfected endothelial cells and the intact cells harvested six days after infection, we compared the expression of cell-surface proteins on these two cell populations by flow cytometry. Because the cells harvested at six days post-infection persisted in culture as nonadherent cells, we chose to investigate surface expression of the adhesion markers intercellular adhesion molecule-1 (ICAM-1, CD54) and vascular cell adhesion molecule-1 (VCAM-1, CD106). Additionally, we analyzed cells for surface expression of Thy1, a cell surface protein which is upregulated on the surface of activated endothelial cells and functions in cell-cell interactions [30] [31] [32] . Uninfected MB114 cells expressed ICAM-1, VCAM-1, and Thy1 (Fig. 6B) . In contrast, infected endothelial cells expressed neither ICAM-1 nor VCAM-1, but did express Thy1. Based on these data, cHV68 infected endothelial cells downregulate cell surface expression of two adhesion molecules, while maintaining surface expression of an activation marker.