Dynamics of Natural Killer Cell Function upon Recurrent Stimulation

For development of economical off-the-shelf allogeneic therapies, maximal expansion of the NK cells from each donor must be achieved while maintaining efficacy and uniformity of the cell product. The most robust expansion method utilizes weekly stimulation with engineered feeder cells derived from the K562 cell line.

However, the effects of repeated stimulation on NK cell growth, metabolism, and function are not well understood. In this study, we demonstrated a distinct shift in growth kinetics and metabolism around week 3-4 of repeated K562 feeder cell stimulation, followed by a change in cytokine secretion and killing ability. While Seahorse metabolic flux assays and transcriptomics suggested a transition from glycolytic metabolism to oxidative metabolism after the first week of stimulation, the shift in growth kinetics generally correlated to reduced metabolic activity.