Combination of interleukin-2-stimulated lymphocytes and bispecific antibodies that efficiently lyse leukemic cells does not affect bone marrow CD34-positive stem cell function in vitro.

We have recently reported that a combination of lymphokine-activated killer (LAK) cells and bispecific antibodies (BsAb) efficiently lysed autologous and allogeneic leukemic blasts that had surface antigens reactive with the BsAb. The effector cells used in that experiment were peripheral blood mononuclear cells stimulated with interleukin-2 (IL-2) for 2 weeks, with the initial addition of anti-CD3 moAb; these were termed T3-LAK effector cells. In this study, we examined the effects of T3-LAK cells and BsAb on autologous normal CD34 + BM cells in both cytotoxicity and colony formation assays