IL-2 and IL-15 transgenic CTLs maintain their antigen specificity. EBV-CTLs transduced with either ΔCD34v or iC.ΔCD34/IL-2v or iC.ΔCD34/IL-15v vectors were analyzed for their phenotype and antigen specificity. Panel A illustrates the phenotypic analysis of transduced EBV-CTLs. Data represent the mean (± SD) of 5 donors. Panel B illustrates the result of a standard ⁵¹Cr release assay in which killing by CTLs of autologous LCLs, allogeneic LCLs, HSB-2 and K562 cell lines was tested at an E/T ratio of 20:1. Data represent the mean (± SD) of 5 donors. Panel C illustrates a representative staining of EBV-CTLs using tetramers targeting the HLA-B8 BZLF1 peptide RAKFKQLL and the HLA-A2 LMP-2 peptide CLGGLLTMV. Panel D illustrates the IFN-γ ELIspot assay of EBV-CTLs tested against the EBV-peptides HLA-A2 LMP-2 CLGGLLTMV, HLA-B8 EBNA3A FLRGRAYGL and HLA-B8 BZLF1 QAKWRLQTL. Data represent the mean (± SD) of 3 donors.