EBV-CTLs genetically engineered to express CNA12 showed improved expansion and persistence in vivo in the presence of FK506. (A) Persistence in vivo of genetically engineered human EBV-CTLs transduced with CNA12 or eGFP. Peripheral tail vein blood was collected from mice the day of sacrifice (40 days after CTL infusion) and quantified by flow cytometry for the persistence of human CD3⁺. Mean cell count ± SEM is shown (n = 8). (B) eGFP expression on human CD3⁺ T cells from the peripheral blood of treated mice measured by flow cytometry. Mean eGFP⁺ expression frequency ± SEM per group is shown (n = 8).