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Updated: Feb 4, 2026

A Novel Feeder-free System for Mass Production of Murine Natural Killer Cells In Vitro
Published on: January 9, 2018
X-ray as Irradiation Alternative for K562 Feeder Cell Inactivation in Human Natural Killer Cell Expansion
Gwang Ho Kim1, Hoang-Nguyen Dang1, Minh-Trang Thi Phan2,3
1Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Republic of Korea.
Background/Aim:
γ-Irradiation has been proven to be the most effective method to inactivate K562 cells, but γ-irradiators are not available in some institutes. This study was designed to compare the effects of X-ray and γ-irradiation on K562 cells in natural killer (NK) cell expansion.
Materials And Methods:
To expand NK cells, isolated peripheral blood mononuclear cells (PBMCs) were co-cultured with γ-irradiated or X-ray-treated K562 cells plus IL-2 and IL-15. Characteristics of expanded NK cells were identified by flow cytometry.
Results:
NK cell expansion rate tended be to lower in the X-ray-treated group (68.9±32.6) than the γ-irradiated group (78±28.7), but the difference was not significant (p=0.39). Furthermore, NK cell functions or receptor expression were similar in the two groups.
Conclusion:
Our results suggest that X-ray treatment can be used as an alternative to γ-irradiation for K562 cells inactivation in human NK cell expansion.
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