Schematic diagrams of in vivo experiments in leukemic mice. (A) Mice were injected with wild-type WEHI-3B cells and survival was measured. (B) Mice were injected with irradiated WEHI-3B–lacZ, WEHI-3B–GM-CSF, WEHI-3B–GM-CSF plus WEHI-3B–IL-4, or WEHI-3B–GM-CSF plus WEHI-3B–TNF cells. One week later, mice were injected with wild-type WEHI-3B cells and survival was measured. (C) One group of mice was injected with wild-type WEHI-3B cells. A second group of mice was injected with irradiated, modified cells as described in (B), above. After 7 days, the latter mice were killed and BMMNCs from these animals were injected into the first group of mice.