POPULATION-DYNAMICS OF HUMAN ACTIVATED NATURAL-KILLER-CELLS IN CULTURE

The growth kinetics and population dynamics of recombinant interleukin -2 (rlL-2) stimulated human natural killer (NK) cell-enriched populati ons were studied in vitro. The NK-enriched population was obtained fro m normal peripheral blood mononuclear cells (PBMNC) by immunomagnetic bead depletion of CD3(+) and CD5(+) T cells. The growth kinetics of NK cells, T cells, monocytes, and total cells are shown. In the absence of PBMNC accessory cells, the NK-enriched population showed limited ex pansion. In the presence of PBMNC accessory cells, the NK-enriched pop ulation expanded threefold more than in the absence of accessory cells due to increased NK cell growth rate and increased duration of expone ntial growth. Using a Transwell system, which cell populations by a po lycarbonate accessory cells were shown to act on the NK-enriched popul ation via a diffusible factor. Accessory cell conditioned media was ab le to replace the accessory cell population to stimulate NK cell expan sion. A monocyte-enriched population prepared by sheep red blood cell resetting of T cells was extensively phenotyped and compared with the NK-enriched populations. Although the final cultured cells were phenot ypically homogeneous for CD56(+)/CD3(-) NK cells, the initial NK precu rsor populations appear to be different. Namely, the NK cell precursor s in the monocyte-enriched population were predominantly CD56(+)/CD2(- ). Kinetic equations were formulated for this culture system and the e ffects of major culture variables are investigated. (C) 1994 John Wile y and Sons, Inc.