FIG. 4.
H1IT immortalizes human PBMCs. A total of 1 × 106 729, 729-HTLV-1, and 729-H1IT producer cells were lethally irradiated and cocultured with 2 × 106 freshly isolated PBMCs in 24-well plates. (A) To follow the immortalization process, growth curves were determined by monitoring cell number and viability by trypan blue exclusion at weekly intervals. Cells were fed once per week with RPMI 1640 supplemented with 20% FBS and IL-2. The mean and standard deviation of each time point were determined from three independent samples. (B) The presence of HTLV gene expression was confirmed by detection of structural Gag protein in the culture supernatant by p19 Gag ELISA. The mean and standard deviation of each time point were determined from three independent samples.