Characteristics of CD19.CAR-VSTs. (A) Transduction of VSTs with the CD19.CAR is shown as both percentages of T cells on flow cytometry and number of copies on Q-PCR. Each symbol represents a patient, with the marker style corresponding to the same patient across the characteristics measured. (B) Phenotypic characteristics of CD19.CAR-VSTs as measured by flow cytometry. (C) Cytotoxic specificity of CD19.CAR-VSTs as measured by ⁵¹Cr release assays against different targets: control PHA blasts, PHA blasts loaded with virus-derived peptides or CD19⁺ cells. (D) IFNγ ELISpot of CD19.CAR-VSTs against different viral-antigen–loaded and CD19⁺ target cells.