Derivation of uninfected and KSHV-infected DMVECs. (A) Phase image of uninfected DMVECs showing the classical cobblestone appearance of normal endothelial cells. (B) Phase image of age- and passage-matched KSHV-infected DMVECs showing spindle cell morphology following viral infection. (C) Phase image of KSHV-infected DMVECs demonstrating loss of contact inhibition. Image shows approximately 3 layers of cells in a 3-dimensional focus. (D) Corresponding immunofluorescence microscopic image showing staining for the latent viral protein ORF 73/LANA (red) and the lytic viral protein ORF 59/progressivity factor-8 (green). Cells were used for experimentation at 3 weeks after infection when more than 90% of cells stained positively for ORF 73. Spontaneous lytic reactivation of KSHV, as assessed by ORF 59 expression, was generally restricted to less than 2% of cells. Original magnification, × 20.