FLOW CYTOMETRIC CHARACTERIZATION OF PROLIFERATING NATURAL-KILLER LYMPHOCYTES FROM BONE-MARROW DONORS IN THE MIXED LYMPHOCYTE-REACTION

Detection of natural killer (NK) cells in the mixed lymphocyte reactio n (MLR) was investigated by flow cytometry and cytotoxicity toward the K562 cell line. Peripheral blood mononuclear cells (PBMCs) from norma l individuals were stimulated with either lymphoblastoid cell Lines (L CLs) or PBMCs. This approach allowed the following observations: 1) af ter stimulation by LCLs, the percentage of NK cells increased concomit antly with the level of cytotoxicity, in contrast to when PBMCs were u sed as stimulators; 2) anti-interleukin-2 monoclonal antibody strongly inhibited NK proliferation in the MLR, but antibody to interferon gam ma did not; and 3) purified NK cells were unable to proliferate agains t LCLs, AU these data suggest that NK cells induced by LCL stimulators depend on T cells to proliferate in the MLR, Flow cytometric detectio n of NK cells in the MLR was also used on cryopreserved PBMCs from 31 bone marrow donors, because it has been reported that an enhanced dono r NK cell activity was correlated with the development of graft-versus -host disease after HLA-identical sibling bone marrow transplantation. NK cell proliferation under LCL stimulation was intense and varied gr eatly among the donors tested. However, no statistical correlation was observed between LCL-induced donor NK cell proliferation in the MLR a nd the occurrence of graft-versus-host disease after bone marrow graft ing. (C) 1998 Wiley-Liss, Inc.