Autologous mature DCs pulsed with EBV B-LCL cells versus freeze–thaw lysates stimulate anti-EBV CD8⁺ CTL in vitro.

CD8⁺ T cells were purified from the blood of EBV-seropositive donor IP2 and were then repetitively stimulated on a weekly basis (days 0, 7, and 14) with autologous intact EBV B-LCL cells (●) or with autologous mature DCs preloaded with freeze–thaw lysates (10 kd or larger) prepared from autologous EBV B-LCL (○), autologous T-cell blasts (■), or allogeneic EBV-B LCL of donor IP1 (▾). On day 23 of culture, responder lymphocytes were harvested and were tested in a 6-hour ⁵¹Cr release assay at the indicated effector-to-target ratios for cytolytic activity against autologous EBV B-LCL (A) or autologous T-cell blasts (B) in the presence of a 20-fold excess of nonlabeled K562 competitors. For all responder lymphocyte cultures, lysis of labeled K562 in the presence of a 20-fold excess of nonlabeled K562 was below 5% at all effector-to-target ratios evaluated (not shown). The data depicted are from 1 representative experiment of 3 performed.