Full-length Tat protein is more potent than Tat-BR peptide at promoting KSHV cell entry. (A) Fluorescence microscopy of HDMECs 24 hours after infection with rKSHV-GFP in the presence of Tat-CR (100 μM) and Tat-BR (100 μM) peptides or recombinant Tat protein (0.5 μM or 0.1 μM). The nucleus of endothelial cells is blue, as revealed by DAPI staining in the KSHV-infected cells (green). Original magnification, × 100. (B) Flow cytometry profile of GFP fluorescence in HEK293 cells exposed to rKSHV-GFP in the presence of Tat-BR peptide (100 μMor20 μM) or full-length Tat protein (0.5 μM, 0.167 μM, or 0.055 μM). The fold increase of the GFP-positive proportion compared with cells infected with rKSHV alone is shown. Mean ± SD (triplicate samples) in a representative of 4 independent experiments. ^*P < .05 compared with rKSHV alone.