Generation of cytotoxic lymphocytes in vitro against autologous human leukaemia cells

Abstract

NORMAL lymphocytes cultured with allogeneic cells in one-way mixed leukocyte culture (MLC) respond proliferatively to the “lymphocyte-defined” (LD) antigens and subsequently cytotoxic cells are generated against the target antigens on the stimulating cells¹. In contrast, when responding lymphocytes are cultured with stimulating lymphocytes that differ with respect to target antigens but not LD antigens, proliferative and cytotoxic responses are not easily generated; the addition of a second stimulating cell differing from the responding cell with respect to LD antigens in a ‘three-cell’ experiment allows the generation of cytotoxic lymphocytes directed against target antigens^1–4. Consistent with results of others^5–9, we have detected low but significant MLC responses after culturing remission lymphocytes with irradiated autologous leukaemia cells; however, cytotoxic lymphocytes were not generated. Using the ‘three-cell’ approach, where remission lymphocytes, irradiated leukaemia cells and irradiated allogeneic stimulating cells were cocultured, we have generated lymphocytes specifically cytotoxic for autologous human leukaemia cells.