EBV-CNA12-CTLs infiltrate B-cell lymphoma despite the presence of FK506. (A) Tumors were collected 40 days post-CTL infusion and stained by double immunofluorescence for human T-cell infiltration (CD3 expression, green) into B-cell lymphoma (CD20, red). Tumors treated with CNA12-CTLs show a substantial T-cell infiltration despite the presence of FK506. Representative sections are shown at 100× magnification. (B) CN-resistant EBV-CTLs do not infiltrate and do not induce toxicity in organs. Organs were collected 40 days post-CTL infusion and stained for human T-cell infiltration (CD3 expression). Organs from mice treated with CNA12-CTLs do not show any T-cell infiltration in the brain (A), intestine (B), heart (C), kidney (D), lungs (E), or liver (F). Representative sections are shown at ×20 magnification.