NK细胞表面CD160分子表达及其介导NK杀伤效应机制的初步研究

A Preliminary Study on the Expression of CD160 on NK Cells and Its Mechanism of Mediating NK Killing Effect

目的:研究CD160分子在人自然杀伤(NK)细胞中的表达及与血液肿瘤的可能关系。方法:从RNA和蛋白水平确定人白血病细胞系NK92细胞表达CD160,并检测该细胞系的增殖特征及细胞表面分子的表达特点。建立以NK92为效应细胞、人白血病细胞系K562或THP-1为靶细胞的杀伤反应体系。加入CD160阻断抗体CL1-R2后,明确其对NK92细胞杀伤功能的影响。同时,采用流式细胞术检测不同种类初发血液肿瘤患者的外周血标本中NK细胞的CD160表达水平。结果:RT-PCR及Western blot杂交检测到NK92表达CD160,流式细胞学检测到NK92细胞表面CD160表达强阳性。NK92可有效杀伤2种白血病靶细胞,抗体阻断CD160后,NK92的杀伤功能被显著抑制。2种靶细胞均高表达HVEM,而K562不表达HLAⅠ类分子。不同种类血液肿瘤患者的外周血CD3-CD56+NK细胞CD160表达均低于正常对照细胞。其中急性髓系白血病(AML)、慢性淋巴细胞白血病(CLL)和异基因造血干细胞移植(allo-HSCT)受者组与正常对照之间有显著性差异(P <0. 05)。结论:人CD160分子参与并介导了NK细胞的部分杀伤功能,血液肿瘤患者NK细胞表面CD160分子表达存在不同程度的下降,提示CD160表达的下调可能是血液系统肿瘤免疫逃逸的一种新机制。

Objective:To investigate the expression of CD160 on the surface of human natural killer(NK)cells and its possible relationship with hematological malignancies.Methods:CD160 expression on human leukemia cell line NK92 cells was confirmed by reverse transcription-polymerase chain reaction(RT-PCR)and Western blot.The proliferation characteristics and cell surface malcers of this cell line were determined.Cytotoxicity of NK92 against 2 human myeloid leukemia cell lines,K562 and THP-1 was analyzed ep viw.CD160 blocking antibody CL1-R2 was employed to clarify its role in NK cell mediated cytolysis.Then,the expression of CD160 on NK cells in peripheral blood from various patients with hematological malignancies were measured by flow cytometry.Results:The mRNA and protein levels of CD160 expressions on NK92 cells were confirmed by RT-PCR and Western blot,respectively.The flow cytometry results demonstrated that the strong positive expression of CD160 could be detected on the NK92 cell surface.NK92 could effectively kill K562 and THP-1 cells,while the cytolysis effect was abrogated in the presence of CD160 blocking antibody CL1-R2.The high levels of HVEM were expressed on both target cells,but the HLA class I molecules were absent on K562.The expression of CD160 on CD3-CD56+NK cells in peripheral blood from patients with acute myeloid leukemia(AML),chronic lymphocytic leukemia(CLL)and allogeneic hematopoietic stem cell transplantation(allo-HSCT)recipients was significant lower than that in the normal controls(P<0.05).Conclusion:The cytolysis function of human NK cells is mediated partially by CD160 molecule.The decrease of CD160 expression on NK cells from patients with various hematological malignancies implies that down-regulation of CD160 expression may be a novel mechanism of tumor immune escape.