Effects of HIV-1 Tat peptides on KSHV infectivity. (A) Fluorescence and phase-contrast microscopy of HEK293, HDMECs, and HUVECs 24 hours after infection with rKSHV-GFP in the absence (left) or presence (right) of Tat-BR peptide (100 μM). Original magnification, × 100. (B) Expression of KSHV LANA, as visualized with Alexa 594 (red) localized to the blue nucleus (DAPI [4′,6-diamidino-2-phenylindole]) in HUVECs infected by KSHV, as revealed by GFP. Merged 3-color image demonstrates the typical speckled pattern of nuclear LANA expression. Original magnification, × 320. (C) GFP-positive population in HEK293, HDMECs, and HUVECs analyzed by flow cytometry. Mean ± standard deviation (SD; triplicate samples) in a representative experiment. ^*P < .05 compared with rKSHV alone.