[In Vitro Amplification of NK Cells from Feeder Layer Cells Expressing IL-21].

Objective: To investigate the effect of feeder layer cells expressing interleukin (IL)-21 on the amplification of NK cells In Vitro .

Methods: The K562 cell line with IL-21 expression on its membrane was constructed by electroporation, and co-cultured with NK cells after inactivation. The proliferation of NK cells was observed. The killing function of the amplified NK cells In Vitro was evaluated by the lactate dehydrogenase (LDH) and interferon-γ (IFN-γ) release assay. A colorectal cancer xenograft model in NOD/SCID mice was established, and a blank control group, a NK cell group and an amplified NK cell group were set up to detect the tumor killing effect of amplified NK cells in vivo.

Results: K562 cells expressing IL-21 on the membrane were successfully constructed by electroporation. After co-culturing with K562 cells expressing IL-21 on the membrane for 17 days, the NK cells increased to 700 times, which showed an enhanced amplification ability compared with control group (P < 0.001). In the tumor cell killing experiment In Vitro , there was no significant difference in the killing activity on tumor cells between NK cells and amplified NK cells, and there was also no significant difference in mice in vivo.

Conclusion: K562 cells expressing IL-21 on the membrane can significantly increase the amplification ability of NK cells In Vitro , but do not affect the killing function of NK cells In Vitro and in vivo. It can be used for the subsequent large-scale production of NK cells In Vitro .