In vitro–expanded T cells were able to proliferate in response to uninfected autologous CLL cells. T cells expanded in vitro after 3 rounds (21 days) of stimulation with autologous MVA-TRICOM–infected CLL cells and exogenous IL-2 were incubated in the presence of autologous, uninfected CLL cells. Panels A and B correspond to the results with 2 different T-cell cultures, established from 2 different patients with CLL (patients 8 and 11, respectively). Abs (20 μg/mL) directed against MHC class I, class II; or an IgG control were added to the uninfected CLL cells for 1 hour before the addition of the T cells. Results are expressed as Stimulation index, calculated as cpm (T cells + CLL cells) / cpm (T cells alone).