Heterogeneity of Human Natural Killer Cells 1,2

ABSTRACT-The cell surface antigens and specificity of cultures of human natural killer (NK) cells, propagated in the presence of interleukin 2, were analyzed at the single-cell level. With the use of a micropipette isolation procedure, clones were initiated from cells of defined phenotype. The cell surface markers on the resultant clones were not stable and often diverged from those on the cells selected for initiation. Clones manifesting NK activity had low expression of T4 and T8 and most had some expression of T10, whereas clones without detectable cytotoxic activity had a considerable proportion of cells expressing T 4 and/or T8 antigens. Within a cytotoxic clone, single cells shown to have killer activity were shown to express often T10 and infrequently T8; T4 was not detected on any of the reactive cells examined. The NK, reactive cells were found to express also antibody-dependent cell-mediated cytotoxicity and lectin-dependent cell-mediated cytotoxicity (LOCC), and some o