Expression of hTERT mRNA in Tax-expressing T cells. (A) Quantitative real-time RT-PCR of hTERT mRNA expression in primary T cells transduced by Tax at 72 hours in the presence or absence of PHA. Results were normalized to represent 100% of transduced cells. (B) Quantitative real-time RT-PCR of hTERT mRNA expression in primary T cells transduced by Tax after 8 weeks of culture in IL-2–supplemented media without stimulation; expression of hTERT in MT-2 cells is given for reference. Experimental variations are indicated by error bars. As shown in Figure 1A, the expression level in nonactivated cultured PBMCs was defined as 1.0. (C) Immunofluorescence of Tax expression in transduced T cells using a mouse monoclonal antibody (Ab); untransduced PBMCs are shown as negative control (bottom panel) and DAPI stain (right). Experimental variations are indicated by error bars. (D) Southern blot analysis of telomere length in HTLV-I–transformed HUT-102 cell line, Tax-transduced PBMCs, and control GFP-transduced PBMCs after 10 weeks of culture in RPMI 1640, 20% FBS, and IL-2. Positive and negative controls were provided by the kit (Intergen).