Concentration-dependent augmentation of anti-K562 activity following short-term culture of null cell-enriched human blood lymphocyte populations

Abstract

The increase in natural cell-mediated cytotoxicity against K562 cells following short-term culture (e.g. 12 hours) of null cells was dependent upon the concentration of cells during incubation. The increased lytic activity by cells cultured at higher concentrations was associated with increased numbers of target-binding cells. It occurred with a variety of serum supplements in the medium. The augmentation of natural killer activity required close cellular proximity or contact and was not associated with detectable increased release of interferon or interleukin 2, although the participation of these molecules cannot be excluded. The lower recovery of lytic activity from cells incubated at lower concentrations was not associated with increased PGE synthesis.