Phenotypic analysis of CLL cells after infection with either MVA-WT or MVA-TRICOM. Flow cytometry analysis of PBMCs from patients 1 (A) and 14 (B) uninfected or 24 hours after infection with 5 MOI of MVA-WT or 5 MOI of MVA-TRICOM. After infection with MVA-TRICOM, 2 populations of CLL cells that expressed either low or high levels of each costimulatory molecule were observed; these were designated here as “low MFI” (L) and “high MFI” (H) populations, respectively.