Abstract
Recently, immunotherapy for leukemia have been carried out with chemotherapy in many institutes including our laboratory. This study was examined ex vivo adoptive immunotherapy (AIT) for leukemia. Short time incubation of lymphokine activated killer (LAK) cells with CD3 monoclonal antibody (moAb) in effector phase resulted in augmentation of LAK activity in 10 of 15 patients with acute leukemia. There was correlation between LAK activity and the expression of Fc receptor on the leukemia cells. Though treatment with CD3 or CD2 moAb for LAK cells could enhance the level of calcium influx, and CD3 moAb could augment LAK activity, but CD2 moAb failed to augment. An interesting observation was the significant activation of LAK cells by stimulation with CD3 moAb, but not by CD2 moAb. CD3 moAb dependent activation of LAK cells may determined by several factors including the expression of Fc receptor on leukemia cells, it was possible that cross-linking of CD3 moAb on LAK cells and Fc receptor on leukemia cells. Furthermore, there was possibility CD3 moAb specific signal transduction induced augmentation of killing activity. This CD3 moAb induced effector cell has strong anti-leukemia effect and may play a significant role in the AIT.
