WT4 cells maintain high telomerase activity. (A-B) Real-time PCR expression of hTERT (A) and TRAP analysis of telomerase activity (B) in Tax-transduced PBMCs (Tax/PBMC no. 3), WT4, and the HTLV-I–immortalized cell lines, MU04 and 1185. Real-time PCR was performed in duplicate; error bars represent the threshold cycle (CT) SD of the gene of interest. Fold changes were calculated by comparing values with that of MU04 normalized gene expression. (C) Western blot analysis of Tax, p53, Bcl-xL, Mcl-1, IκBα, and actin in WT4 cells compared with the HTLV-I–transformed cell line, MT4. Nontransduced resting PBMCs (RPBMCs) and activated PBMCs (ActPBMCs) served as controls. (D) Cell-cycle analysis of WT4 cells cultured 72 hours without IL-2 and/or restimulated overnight with IL-2. (E) Cell-cycle analysis of PBMCs transiently transduced with a Tax-GFP or GFP-control virus. FACS analysis was performed 48 hours after infection on GFP (infected) sorted cells.