The impact and applications of high-dose fractionated irradiation on the effector function of NK cells
10.3760/cma.j.cn112271-20250318-00093
- VernacularTitle:高剂量分割照射对NK细胞效应功能的影响及应用
- Author:
Liting XIONG
1
;
Chunxiao LI
;
Junjie WANG
Author Information
1. 北京大学医学部医学技术研究院，北京 100191
- Publication Type:Journal Article
- Keywords:
High-dose fractionated irradiation;
Natural killer cells;
T-cell immunoreceptor with Ig and ITIM domains (TIGIT)
- From:
Chinese Journal of Radiological Medicine and Protection
2025;45(7):623-628
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the impact of high-dose fractionated irradiation on NK cell function and immune checkpoint expression.Methods:A total of 10 female C57BL/6N mice aged 6-8 weeks were subcutaneously injected with Lewis lung carcinoma (LLC) cells on the right shoulder to establish a subcutaneous tumor model. Mice were randomly divided into two groups: the control (Ctrl) group and the radiation (RT) group, with five mice in each group. The RT group received fractionated irradiation of 8 Gy × 3 fractions, while the Ctrl group was not irradiated. Three days later, flow cytometry was performed to compare the numbers of NK cells and the expressions of immune checkpoints, including programmed death-1 (PD-1) and T-cell immunoreceptor with Ig and ITIM domains (TIGIT), in the spleen, draining lymph nodes, and tumor tissue between the two groups. The activation state and cytotoxicity of NK cells were assessed by the expression of lysosomal-associated membrane protein 1 (CD107a) on the NK cell surface. Additionally, a second experiment was conducted with 20 tumor-bearing mice divided into four groups: Ctrl, RT, anti-TIGIT (αTIGIT) treatment, and RT combined with αTIGIT treatment (RT+ αTIGIT), with five mice per group. The RT and RT+ αTIGIT groups received fractionated RT, while the αTIGIT and RT+ αTIGIT groups were treated with blocking antibody αTIGIT at 0.5 mg/kg every 3 days and the Ctrl group was treated with isotype control IgG. Tumor size was monitored during the experiment. On day 20, mice were euthanized, Ki67 immunohistochemistry and TUNEL immunofluorescence staining were used to evaluate tumor cell proliferation and apoptosis.Results:Compared with the Ctrl group, fractionated high-dose RT resulted in a decrease in NK cell numbers in the spleen, tumor-draining lymph nodes, and tumor microenvironment in the RT group ( t=6.79-7.54, P<0.05), together with a significant upregulation of the mean fluorescence intensity of PD-1 and TIGIT ( t=4.16-5.65, P<0.05; t=6.12-21.13, P<0.05), and a decrease in CD107a+ expression ( t=5.64-8.99, P<0.05). Compared with the RT group, the RT+ αTIGIT group showed reduced tumor weight ( t=2.50, 9.12, P<0.05), decreased Ki67 expression ( t=12.10, P<0.05), and increased TUNEL expression ( t=5.42, P<0.05). Conclusions:The fractioned high-dose RT can impair NK cell function and upregulate immune checkpoint expression, thereby limiting the immune response. The combination of irradiation with anti-TIGIT antibody treatment can partially reverse this trend and improve tumor treatment efficacy.
