Abstract
BackgroundCord Blood (CB) has been considered a promising source of natural killer (NK) cells for cellular immunotherapy. However, it is difficult to expand the large numbers of highly pure NK cells from CB without cell sorting and feeder cells/multiple cytokines. In this study, we try to develop a simple, safe and economical method for ex vivo expansion and purification of NK cells from CB without cell sorting and feeder cells/multiple cytokines.ResultsThe large numbers (mean: 1.59 × 1010) of highly pure (≥90%) NK cells from CB could be obtained through interleukin-2, group A streptococcus and zoledronate stimulation of mononuclear cells using the 21-day culture approach. When compared to resting NK cells, expanded NK cells were a higher expression of activating receptors CD16, NKG2D, NKp30, NKp44, NKp46 and activating markers CD62L and CD69, while the inhibitory receptors, CD158a and CD158b remained largely unchanged. In addition, these cells showed a higher concentration of IFN-γ, TNF-α and GM-CSF secretion and cytotoxicity to K562 cells and acute myeloid leukemia targets than resting NK cells.ConclusionWe develop a simple, safe and economical method to obtain high yield, purity, and functionality NK cells from CB without cell sorting and feeder cells/multiple cytokines.
Highlights
Cord Blood (CB) has been considered a promising source of natural killer (NK) cells for cellular immunotherapy
Expansion of CD56+CD3− NK cells was much higher compared with other types of cells, so NK cells dominated at the end of the culture, reaching on average 92.37% of the total cell populations by day 21
At this time point the expansion potential reached a plateau, the cells reached a quiescence phase when measured later on day 28. These data demonstrate that NK cells with high yield and purity could be expanded efficiently from CBderived mononuclear cells (MNCs) ex vivo using the method described here
Summary
Cord Blood (CB) has been considered a promising source of natural killer (NK) cells for cellular immunotherapy. It is difficult to expand the large numbers of highly pure NK cells from CB without cell sorting and feeder cells/multiple cytokines. When compared to resting NK cells, expanded NK cells were a higher expression of activating receptors CD16, NKG2D, NKp30, NKp44, NKp46 and activating markers CD62L and CD69, while the inhibitory receptors, CD158a and CD158b remained largely unchanged. These cells showed a higher concentration of IFN-γ, TNF-α and GM-CSF secretion and cytotoxicity to K562 cells and acute myeloid leukemia targets than resting NK cells.
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