IL-21增强γδT细胞体外抗肿瘤活性的实验研究

探讨IL-21对人外周血γδT细胞抗肿瘤活性的影响。分离健康人外周血单个核细胞(PBMC),分别在有或无IL-21参与的条件下,加入到含异戊烯焦磷酸(isopentenyl pyrophosphate,IPP)、IL-2或IL-15的RPMI 1640完全培养基中诱导培养γδT细胞。在培养的第10天用台盼蓝染色计数细胞;采用流式细胞术检测各组γδT细胞的纯度及γδT细胞穿孔素、颗粒酶B和CD107a的表达;用CCK-8试剂盒检测γδT细胞对K562细胞的体外杀伤效应。结果显示,不同细胞因子组诱导10d后γδT细胞纯度均达到70%以上,IL-2+IL-21、IL-15+IL-21和IL-2+IL-15+IL-21组与IL-2、IL-15组相比,细胞纯度和扩增倍数没有显著性变化;IL-2+IL-21、IL-15+IL-21和IL-2+IL-15+IL-21组γδT细胞穿孔素、颗粒酶B和CD107a的表达及对K562细胞的杀伤活性均显著高于IL-2、IL-15单独组。以上结果表明,IL-21可通过上调γδT细胞穿孔素和颗粒酶B的表达增强其抗肿瘤活性。     

不同细胞因子诱导脐血来源的CIK、NK细胞对K562细胞杀伤活性的研究

目的：了解不同细胞因子组合扩增的脐血CIK、NK细胞对人K562细胞株的杀伤活性的差异性。方法：通过SCF、FLT3L、IL-2、IL-7及IL-15等细胞因子的不同组合扩增的脐血CIK、NK细胞，分为3组，A组（SCF＋IL-2＋IL-7＋IL-15）、B组（SCF＋FLT3L＋IL-2＋IL-7＋IL-15）和C组（IL-2＋IL-7＋IL-15，对照组）；通过MTT法检测各组CIK、NK细胞在不同效靶比下对K562的杀伤率，计算各组的总杀伤单位。结果：经过21天培养A组体系中CIK＋NK细胞的比例平均超过60％，B组CIK＋NK细胞的比例平均超过70％，而C组约为50％；各组扩增的CB-CIK／NK细胞同组间在效靶比20：1时对K562的杀伤率均显著高于10：1（P〈0．01）。在不同效靶比下A组CIK／NK细胞对K562的杀伤率显著高于B和C组（P〈0．01）；C组CIK／NK细胞对K562的杀伤率稍高于B组，但两组间对K562的杀伤率无显著性差异。A组总杀伤单位显著高于C组，与B组无显著差异。结论：不同细胞因子组合扩增的脐血CIK、NK细胞对人K562细胞株的杀伤活性有差异，考虑到对效应细胞的扩增效果，B组为具有最佳杀伤活性的脐血CIK、NK细胞培养体系，其中的SCF、FLT3L对CIK／NK细胞诱导有协同效果。     

K652重组表达IL-6基因对NK细胞表型和功能的影响

目的:为了研究表达IL-6的重组K562细胞对自然杀伤细胞(NK)细胞的扩增数量、表型和功能的影响。方法:根据人类IL-6 c DNA的5'端序列,设计PCR引物以K562细胞c DNA文库的DNA为模板进行扩增,表达,转染,在K562细胞上表达IL-6基因,构建重组的K562工程细胞作为刺激细胞,以人外周血单个核细胞(PBMC)为扩增培养对象,使NK细胞在体外培养条件下得到大量的扩增。流式细胞仪分析NK细胞表型。将NK细胞作用到K562细胞,对其杀伤性进行功能分析,51Cr释放实验检测NK细胞对K562细胞杀伤水平的影响。结果:成功构建了表达IL-6的重组K562细胞,和PBMC共同孵育后,培养体系经过21 d的刺激后,IL-6重组K562细胞诱导PBMC扩增,CD56+CD16+CD3-细胞数量比诱导前扩增了(760±18)倍,CD56+CD16+CD3-细胞的纯度从培养前占PBMC的6%±0.4%,扩增后第3组结果比未扩增的多了91%±2%。细胞毒实验表明,在NK效应细胞∶K562靶细胞为5∶1时,扩增的NK细胞的杀伤率达到了92%±2%。结论:本方法以重组K562为刺激细胞,能够实现NK细胞体外的大规模制备,建立了优化的NK细胞体外扩增方法,且扩增的细胞杀伤K562细胞的活性较好。对于NK的大量扩增和应用于临床具有重要的指导意义。     

TLR7/8配体(R848)对人NK细胞杀伤功能的作用及其机制的探讨

目的研究R848对人自然杀伤细胞(NK)杀伤功能的作用及其机制。方法分离健康志愿者外周血单个核细胞(PBMC)、纯化NK细胞,加或不加R848进行培养。分别在0、2、6、24、48h收集培养细胞,流式细胞术检测R848对NK细胞表面活化分子CD25和CD69表达的影响;检测R848活化的NK细胞杀伤靶细胞K562的作用、通过检测颗粒酶A、B、穿孔素、TRAIL和NK细胞与靶细胞共孵育后CD107a/b的表达,探讨R848促进NK细胞的杀伤功能机制。结果 R848活化的NK细胞在培养24h时CD69和CD25分子的表达百分率和平均荧光密度达到峰值,随后活化分子的表达有所下降;R848活化的NK细胞对靶细胞的杀伤功能明显增强,TRAIL在不同NK细胞亚群的表达显著增加(P0.05)。当NK细胞与K562共孵育后,R848活化的NK细胞表面CD107a/b的表达较未刺激条件明显增加。结论 R848可直接作用于NK细胞促进其杀伤功能,其作用机制与NK细胞活化后释放颗粒酶和穿孔素增加,并且TRAIL的表达增加有关。     

卡介苗(BCG)通过诱导IL-12产生和受体表达促进人NK细胞功能

目的:研究卡介苗(BCG)对人自然杀伤细胞(NK)功能的作用及其机制.方法:分离抗结核抗体阴性志愿者外周血PBMC、纯化NK细胞, 分别与BCG、 IL-12、 BCG+IL-12、 BCG+抗IL-12Rβ1 mAb(2B10)培养.利用ELISA方法检测培养上清液IFN-γ、 IL-12p40含量;利用ELISpot方法检测IFN-γ、颗粒酶B产生细胞的频率;利用四甲基偶氮唑盐(MTT)比色法测定杀伤功能.利用流式细胞术检测NK细胞IL-12Rβ1的表达.结果:BCG呈剂量依赖的方式诱导PBMC产生IFN-γ.在BCG刺激条件下, PBMC颗粒酶B分泌细胞数明显高于不加任何刺激剂组(P<0.05).BCG增强PBMC杀伤活性.BCG不能诱导纯化NK细胞产生IFN-γ, 但与IL-12同时刺激则表现出协同作用.纯化NK细胞经BCG刺激后杀伤活性与未刺激相比差异无统计学意义.BCG呈剂量依赖方式诱导PBMC产生IL-12、并促进NK细胞不同亚群表达IL-12Rβ1.2B10抗体抑制BCG对PBMC产生IFN-γ和分泌颗粒酶B的诱导作用.结论:BCG间接地促进NK细胞的生物学活性, 其部分机制是通过诱导单核细胞产生内源性IL-12、并上调NK细胞表达IL-12R.     

IL-23与IL-12诱导NK细胞功能的异同及机制初探

目的探讨细胞因子IL-23与IL-12对NK细胞功能的影响及可能的机制。方法密度梯度离心法分离人外周血单个核细胞(PBMCs)或磁珠纯化NK细胞,不刺激或用IL-23或IL-12刺激,用流式细胞术和ELISA法检测NK细胞产生IFN-γ的情况;以K562或Jurkat细胞作为靶细胞,用流式细胞术检测NK细胞的杀伤功能并分析NK细胞在不同的刺激条件下杀伤相关分子的表达情况及pSTAT的表达情况。结果与未刺激组相比,IL-23和IL-12均可以诱导NK细胞呈剂量和时间依赖方式产生IFN-γ;但IL-12而非IL-23可以增强NK细胞对靶细胞K562或Jurkat细胞的杀伤功能。进一步研究表明,IL-12而非IL-23可以诱导杀伤相关分子TRAIL及CD107a/b的表达。此外,IL-12诱导NK细胞表达更高水平的pSTAT4,而IL-23诱导NK细胞表达更高水平的pSTAT3。结论与IL-12相比,IL-23亦可以诱导NK细胞产生细胞因子但不能增强NK细胞的杀伤功能,IL-23不能诱导杀伤相关分子TRAIL及CD107a/b的表达,IL-23可以诱导低水平的pSTAT4但高水平的pSTAT3的表达。     

树突状细胞对脐血来源细胞因子诱导杀伤、自然杀伤细胞杀伤活性及CD45RO表达的影响

目的:探索同一来源脐血树突状细胞(DCs)对细胞因子诱导杀伤(CIK)、自然杀伤(NK)细胞杀伤活性和CIK细胞上CD45RO表达的影响。方法:通过细胞因子组合诱导、扩增脐血来源的DCs、CIK和NK细胞,杀伤效应细胞分为两组:A组为接受DCs共孵育6d刺激的CIK、NK细胞,B组为未接受任何刺激的CIK、NK细胞,了解DCs对相应效靶比下CIK、NK细胞杀伤K562、HL-60细胞株细胞毒活性的影响;通过流式细胞术检测两组CIK细胞上CD45RO、CD45RA的表达率。结果:随着效靶比的升高,脐血CIK、NK细胞对肿瘤细胞株的杀伤力增加。在20∶1、10∶1效靶比下,A组CIK、NK细胞对HL-60的杀伤率分别为76.77％±5.76％、55.87％±2.09％,B组为61.14％±3.72％、49.96％±1.51％,A组对HL-60的杀伤明显高于B组;在20∶1效靶比下,A组对K562的杀伤明显高于B组;而在10∶1效靶比下两组之间的杀伤活性未见显著差异;A组CIK细胞上CD45RO表达率显著高于B组。结论:DCs与CIK、NK细胞共孵育可提高CIK、NK细胞的细胞毒活性及增加CIK细胞上CD45RO的表达。     

不同刺激因子组合诱导NK细胞体外扩增及其功能的研究

目的探讨不同刺激因子组合对人自然杀伤细胞(NK细胞)体外扩增及其功能的影响。方法 VarioMACS分选健康成人外周血单个核细胞(PBMC)中的NK细胞,依据添加刺激因子的不同分为A组(IL-2)、B组(IL-2+IL-15)、C组(IL-2+IL-15+饲养细胞),饲养细胞为30 Gyγ射线照射后的同种异体外周血单个核细胞(allogeneic PB-MNCs,AlloMNCs),未添加任何刺激因子的细胞的作为对照组,在干细胞生长培养基(SCGM)中进行培养扩增14 d,第1天添加PHA及OKT3,第5天离心洗去;台盼蓝拒染法进行活细胞计数;流式细胞术检测分选及扩增前后CD56+CD3-NK细胞纯度;改良的MTT法检测NK细胞对K562、HO8910及PBMC的杀伤活性。结果经VarioMACS免疫磁珠阴性分选后NK细胞纯度由分选前的(9.2±2.9)%提高到(93.5±3.2)%,培养14 d后,除对照组NK细胞纯度降低外,其余组与扩增前无明显差异(P>0.05)。细胞扩增倍数分别为17.2±1.7、51.3±6.6和82.4±9.8倍,均显著高于对照组(5.7±1.2)(P<0.01)。实验组组间比较,C组明显高于A组和B组(P<0.01)。细胞杀伤实验表明,当效靶比为10∶1时,各组的杀伤活性显示为C组>B组>A组>对照组,C组扩增的NK细胞对K562及HO8910的杀伤率可分别达到(70.1±8.9)%和(64.6±6.2)%,显著高于对照组、A组(P<0.01)和B组(P<0.05),对PBMC的杀伤率仅为(4.2±1.2)%。结论经VarioMACS分选获得的NK细胞,在体外使用SCGM培养基培养,添加IL-2、IL-15和照射后AlloMNCs作为刺激因子,可获得高效扩增和有效活化的NK细胞,为NK细胞的肿瘤过继免疫治疗提供了一种简单有效的扩增高纯度NK细胞的方法。     

应激对鼠脾NK细胞穿孔素及颗粒酶的mRNA表达的影响

目的：阐明躯体性应激和心理性应激降低NK细胞杀伤活性的机制及异同。方法：应用Communication box系统分别使小鼠连续负荷躯体性应激和心理性应激后，以放免法检测鼠血浆类固醇激素水平：以^51Cr释放法检测鼠脾NK细胞杀伤活性；以流式细胞术检测鼠脾NK细胞数量；以RT-PCR技术检测鼠脾细胞中杀伤效应介质——穿孔素、颗粒酶A及B的mRNA表达水平。结果：负荷躯体性应激和心理性应激后，小鼠血浆类固醇激素水平升高，分别于第3天和第5天达高峰后，逐渐下降；两者均可导致鼠脾NK细胞数量减少，杀伤活性降低（P〈0．05，P〈0．01）；两者均可导致穿孔素的mRNA表达下降；但躯体性应激降低颗粒酶A的mRNA表达，而颗粒酶B的mRNA表达反而升高；心理性应激可降低颗粒酶B的mRNA表达，虽然也降低颗粒酶A的mRNA表达，但无显著性差异。结论：躯体性应激和心理性应激均可降低脾NK细胞数量及其杀伤活性，但对杀伤效应介质——穿孔素、颗粒酶A及B的mRNA表达的影响不同，提示躯体性应激和心理性应激对NK细胞功能影响的机制不同。     

儿童EB病毒相关噬血细胞淋巴组织细胞增生症NK细胞表面受体和CD107a表达

目的研究儿童EB病毒相关噬血细胞淋巴组织细胞增生症（EBV-HLH）NK细胞表面受体和CD107a表达,为深入了解EBV-HLH发病机制提供理论依据。方法选取2009年8月至2011年5月于北京儿童医院确诊为EBV-HLH、未接受过化学免疫治疗的住院患儿为EBV-HLH组,选取年龄、性别与EBV-HLH组1∶1匹配的健康查体儿童为正常对照组。应用流式细胞仪检测NK细胞表面受体、穿孔素及CD107a表达。予IL-2刺激后再次测定CD107a表达情况。结果 EBV-HLH组和正常对照组各8例。①两组NK细胞表面受体NKp30、NKp46、NKG2D、DNAM-1和2B4表达阳性率差异均无统计学意义,CD56＋NK细胞穿孔素表达率和CD8＋T细胞穿孔素表达率差异均无统计学意义。②两组在IL-2刺激前CD107a、CD107a/K562、CD107a/2B4/P815、CD107a/NKG2D/P815和CD107a/2B4/NKG2D/P815表达率差异均无统计学意义。③EBV-HLH组在IL-2刺激前后CD107a表达差异无统计学意义;正常对照组IL-2刺激前后CD107a、CD107a/K562和CD107a/NKG2D/P815表达率差异有统计学意义。结论 EBV-HLH患儿NK细胞对IL-2的反应出现异常,可能与EBV-HLH的发生有关。     

NK 细胞的高效扩增及其对体外肿瘤模型的杀伤效果研究

目的:高效扩增NK 细胞,并确定其对不同肿瘤的杀伤作用,为临床应用提供参考。方法:从成人外周血中分离PBMCs 并利用表面表达4-1BBL、IL-15 和IL-21 的K562 滋养细胞对其进行共刺激培养,15 d 后计数并检测CD3- CD56+细胞纯度;利用间接免疫荧光及Real-time PCR 方法检测NK 细胞Granzyme B 及Perforin 表达变化的同时检测其对肺癌、胃癌、肝癌、卵巢癌、胰腺癌、宫颈癌的杀伤作用,确定其对不同肿瘤的杀伤效果。结果:扩增15 d 后,细胞数量高于110 ‘,CD3-CD56+比例达95%以上;培养后的NK 细胞高表达Granzyme B、Perforin,且对A549 的杀伤效果(E:T=10 :1)约为90%,同时对其他肿瘤细胞(E:T=10:1)的杀伤效果由强到弱的顺序为:胃癌、胰腺癌、宫颈癌、卵巢癌、肾癌、肝癌(P<0.05);NK 细胞对宫颈癌、肝癌、胰腺癌的杀伤效果呈现一定的时间依赖性。结论:此方法可以扩增出高数量、高纯度的NK 细胞,同时该NK 细胞具有高效杀伤多种肿瘤细胞的能力。     

Acquisition of murine NK cell cytotoxicity requires the translation of a pre-existing pool of granzyme B and perforin mRNAs

Although activated murine NK cells can use the granule exocytosis pathway to kill target cells immediately upon recognition, resting murine NK cells are minimally cytotoxic for unknown reasons. Here, we showed that resting NK cells contained abundant granzyme A, but little granzyme B or perforin; in contrast, the mRNAs for all three genes were abundant. Cytokine-induced in vitro activation of NK cells resulted in potent cytotoxicity associated with a dramatic increase in granzyme B and perforin, but only minimal changes in mRNA abundance for these genes. The same pattern of regulation was found in vivo with murine cytomegalovirus infection as a physiologic model of NK cell activation. These data suggest that resting murine NK cells are minimally cytotoxic because of a block in perforin and granzyme B mRNA translation that is released by NK cell activation.     

IL-15 induces CD8+ T cells to acquire functional NK receptors capable of modulating cytotoxicity and cytokine secretion

During the last years several authors have described a small population of CD8+ T cells expressing NK receptors (NKRs). Although their origin remains largely unknown, we have recently demonstrated that IL-15 is capable of inducing NKR expression in purified human CD8+CD56− T cells. In this study we show that IL-15-driven NKR induction in CD8+ T cells was linked with CD56 de novo acquisition, consistent with an effector-memory phenotype, increased anti-apoptotic levels, high granzyme B/perforin expression and with the ability of displaying in vitro NK-like cytotoxicity. Interestingly, dissection of NKR functional outcome in IL-15-cultured CD8+ T cells revealed: (i) that NKG2D cross-linking was able per se to upregulate degranulation levels and (ii) that KIR and NKG2A cross-linking upregulated secretion of cytokines such as IFN-γ, TNF-α, IL-1β and IL-10. These results suggest that IL-15 is capable of differentiating CD8+ T cells into NK-like T cells displaying a regulatory phenotype.     

Lipophilic statins suppress cytotoxicity by freshly isolated natural killer cells through modulation of granule exocytosis

NK cells, a component of the innate immune system, provide a first line of defense against viral infections and malignancies, interact with the adaptive immune system and have a role in rejection of allogeneic bone marrow transplants and solid allo- and xenotransplants. Immunoregulatory activity by the anti-hypercholesterolemia agents, 3-hydroxy-3-methyl-glutaryl Coenzyme A (HMG-CoA) reductase inhibitors, known as statins, has recently been reported. We analyzed the effects of three statins on human NK cell cytotoxicity. Two lipophilic statins (simvastatin and fluvastatin) suppressed the cytotoxic activity of fresh and IL-2-stimulated NK cells, while pravastatin, a hydrophilic statin, did not. Suppression was not associated with changes in intracellular perforin, granzyme A or granzyme B levels, or with changes in expression of leukocyte function-associated antigen-1, an integrin known to regulate NK activity and reported to be altered by statin treatment. Decreased cytotoxicity was associated with decreased CD107a surface expression, indicating that the exocytosis pathway was compromised by simvastatin and fluvastatin but not by pravastatin. Mevalonate, the immediate downstream product of HMG-CoA reductase, partially reversed the effect of lipophilic statins on cytotoxicity and CD107a expression. Lipophilic statins also suppressed the release of the granule component, granzyme B, by IL-2-activated NK cells following stimulation with K562. That lipophilic statins suppress NK cell activity through inhibition of the exocytosis pathway suggest an additional potential role for statins in inhibition of transplantation responses.     

IFNalpha2b stimulated release of IFNgamma differentially regulates T cell and NK cell mediated tumor cell cytotoxicity

Interferonalpha2b (IFNalpha2b) augments the suppressed immune functions and peripheral blood mononuclear cell (PBMC) cytotoxicity of head and neck squamous cell carcinoma (HNSCC) patients by differential regulation of IFNgamma, a pleotropic Th1 cytokine. In the present communication, we have examined the role of IFNgamma in IFNalpha2b initiated T and NK cell mediated cytotoxicity of tumor cells. IFNalpha2b activates both T and NK cells to release IFNgamma. IFNgamma plays a crucial role in enhancing tumor cell cytotoxicity by T cells, but not by NK cells, as evidenced by killing of a oral (KB) and breast (MCF7) cancer cells, without affecting the killing of NK sensitive erythroleukemic K562 cells by IFNalpha2b activated PBMC. IFNalpha2b driven tumor cell cytotoxicity is related to the rectification of the downregulated expression of cytotoxic molecules, perforin, granzyme B and FasL in CD8+ T and CD56+ NK cells. Expression of IFNalpha2b mediated perforin and granzyme B is dependent on IFNgamma in T cells, but not in NK cells. However, expression of FasL in both T and NK cells is not dependent on IFNgamma. In conclusion, IFNalpha2b enhances suppressed T cell cytotoxicity of HNSCC patients by stimulating perforin-granzyme B system, which is IFNgamma dependent. IFNalpha2b also induces the expression of perforin-granzyme B system in NK cells, but this NK mediated cytotoxicity is IFNgamma independent.     

Systematic characterization of human CD8+ T cells with natural killer cell markers in comparison with natural killer cells and normal CD8+ T cells

We investigated the function of CD56+ CD8+ T cells (CD56+ T cells) and CD56- CD57+ CD8+ T cells (CD57+ T cells; natural killer (NK)-type T cells) and compared them with those of normal CD56- CD57- CD8+ T cells (CD8+ T cells) and CD56+ NK cells from healthy volunteers. After the stimulation with immobilized anti-CD3 antibodies, both NK-type T cells produced much larger amounts of interferon-gamma (IFN-gamma) than CD8+ T cells. Both NK-type T cells also acquired a more potent cytotoxicity against NK-sensitive K562 cells than CD8+ T cells while only CD56+ T cells showed a potent cytotoxicity against NK-resistant Raji cells. After the stimulation with a combination of interleukin (IL)-2, IL-12 and IL-15, the IFN-gamma amounts produced were NK cells > or = CD56+ T cells > or = CD57+ T cells > CD8+ T cells. The cytotoxicities against K562 cells were NK cells > CD56+ T cells > or = CD57+ T cells > CD8+ T cells while cytotoxicities against Raji cells were CD56+ T cells > CD57+ T cells > or = CD8+ T cells > or = NK cells. However, the CD3-stimulated proliferation of both NK-type T cells was smaller than that of CD8+ T cells partly because NK-type T cells were susceptible to apoptosis. In addition to NK cells, NK-type T cells but not CD8+ T cells stimulated with cytokines, expressed cytoplasmic perforin and granzyme B. Furthermore, CD3-stimulated IFN-gamma production from peripheral blood mononuclear cells (PBMC) correlated with the proportions of CD57+ T cells in PBMC from donors. Our findings suggest that NK-type T cells play an important role in the T helper 1 responses and the immunological changes associated with ageing.     

Involvement of granzyme B and perforin gene expression in the lytic potential of human natural killer cells

Natural killer (NK) cells (CD3⁻) or large granular lymphocytes (LGL) spontaneously kill K562 targets but are unable to kill Daudi cells in the absence of IL-2 stimulation. IL-4 is reported to prevent or inhibit the IL-2-driven lymphokine-activated killer (LAK) generation in NK cells. Therefore, we wished to determine whether the antagonistic effect of IL-4 on IL-2-induced LAK activity might regulate the expression of genes encoding proteins involved in lysis, such as perforin, the pore-forming protein, or which are associated with lysis, such as granzymes A and B. By using in situ hybridization, we showed that, in addition to inducing LAK activity, IL-2 stimulation increased the amount of perforin and granzyme B mRNA at the single-cell level in 40 to 100% of the total CD3⁻ LGL cell population. In addition, our results indicated that the stimulatory effect of IL-2 can be downregulated by IL-4 for both LAK activity and granzyme B and perforin gene expression. Here again, a decrease in the amount of specific mRNA per cell was noted. These findings suggest that modulation of the lytic machinery via lymphokines might be associated with regulation of the lytic potential of NK cells.