CD70-specific T cells recognize and kill primary CD70-positive lymphomas. (A) CD70-overexpressing tumor cells from 3 patients with B-cell lymphoma and 1 patient with T-cell acute lymphoblastic leukemia were cocultured with CD70-specific or nontransduced T cells from healthy donors for 48 hours before performing IFN-γ ELISA. In all cases, CD70-specific T cells released IFN-γ in the presence of patient tumor cells, whereas nontransduced cells released little or no IFN-γ. (B-C) Coculture assays were performed with primary tumor cells and CFSE-labeled T cells to distinguish effector and target cells by FACS analysis. Only CD70-specific (CD3/CFSE–positive) T cells were able to eradicate patient tumor cells (P = .036).