X-ray as irradiation alternative for K562 feeder cell inactivation in human natural killer cell expansion

Abstract

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.