More balance toward activating receptors and cytotoxic activity of NK cells ex vivo differentiated from human umbilical cord blood-derived CD34⁺ stem cells in comparison with peripheral blood NK cells

Adoptive immunotherapies that use functional NK cells depend on the availability of sufficient numbers of these cells. We expanded umbilical cord blood (UCB)-CD34⁺ HSCs for 2 weeks and then differentiated them into NK cells and compared their function to peripheral blood (PB) NK cells. We assessed NKG2D, NKG2A, NKp30, NKp44, NKp46, and the expression of CD107a, CD57, CD69, FasL, PD-1, and IFN-γ level in two groups after co-culture with K562 cell line. We found that UCB-CD34⁺-derived NK cells express significantly more NKG2D, NKp44, and NKp46 receptors than PB NK cells. PB NK cells expressed significantly higher NKG2A and CD57 than UCB-CD34⁺-derived NK cells. In addition, UCB-CD34⁺-derived NK cells significantly expressed CD107a more than PB NK cells. Based on our findings, UCB-CD34⁺ cells can be a potentially advantageous source with strong cytotoxic function to produce allogeneic NK cells for adoptive cancer immunotherapy.