(A) T-cell lines generated from the bone marrow of leukemia patients recognize and proliferate when challenged by unstimulated and CD40-stimulated leukemia cells: Comparison of direct or bystander costimulation. Proliferation was assessed by measuring [³H] thymidine incorporation for the last 18 hours of the 3-day assay. The results shown are from one experiment and are representative of three independent experiments (3 different patients).

(B) T-cell lines generated from the bone marrow of leukemia patients are capable of lysing both unstimulated and CD40-stimulated leukemia cells: Comparison of direct or bystander costimulation. Cytotoxicity was assessed as described in the Materials and Methods. The results shown are from one experiment and are representative of three independent experiments (3 different patients).