[ 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 .

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 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 .

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 ( < 0.001). In the tumor cell killing experiment , 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 .

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