INDUCTION OF CYTOTOXIC LYMPHOCYTE SUBSETS AGAINST LEUKEMIA BY STIMULATION WITH AML BLASTS

Although the application of interleukin-2 (IL-2) activated lymphocytes in immunotherapy of acute myelogenous leukemia (AML) is of therapeuti c interest, the high resistance of AML blasts to lymphocyte lysis may represent an obstacle to this type of therapy. However, our data shows that the leukemia resistance can be conquered by concomitant culture or lymphocytes with IL-2 and AML blasts. This approach induces not onl y leukemia-directed cytotoxic cells, but also promotes their growth. A dditionally, multiple cytotoxic lymphocyte populations with leukemia l ytic activity are induced in AML/IL-2 cultures. These include natural killer (NK) cells and subsets of T cells with both the major histocomp atibility complex (MHC)-restricted and MHC-nonrestricted cytotoxic fun ction. Thus, this protocol, which is conducive to general stimulation of cellular immune responses against leukemia, may enhance the benefit s of lymphocyte therapy.