HIV/HCV共感染者自然杀伤细胞表面活化性与抑制性受体表达的研究

目的 比较HIV/HCV共感染、单纯HCV感染、单纯HIV感染者和健康人自然杀伤细胞（NK）数量及其表面受体的变化,了解HIV/HCV共感染者NK细胞表面活化性与抑制性受体表达特点.方法 采用流式细胞术对24例HIV/HCV共感染者,28例单纯HCV感染者,21例单纯HIV感染者外周血NK细胞数量与其表面活化与抑制性受体进行检测并与20例健康人进行比较分析.结果 HIV/HCV共感染组NK细胞绝对值较其他3组显著减少;共感染组、单纯HIV感染组、单纯HCV感染组NK细胞上NKP30和NKP46的表达频率都显著低于健康对照组,但NKP30的频率在前3组之间差异无统计学意义.共感染组和单纯HIV感染组的NKP46表达频率都显著低于HCV单纯感染组,而前2组之间差异无统计学意义;共感染组和单纯HCV感染组的NKG2A表达频率显著高于健康对照组和单纯HIV感染组,而前2组之间差异无统计学意义,但单纯HIV感染组NKG2A表达频率显著低于健康对照组;NK细胞NKG2D、CD158a和CD158b的表达频率在各组间差异无统计学意义.结论 HIV/HCV共感染者NK细胞绝对值明显降低,其表面活化性受体表达减少,某些抑制受体表达增加,甚至高于单纯HIV感染者,HIV/HCV共感染者NK细胞受损更加严重.     

重组可溶性MHC Ⅰ类相关蛋白A对NK细胞生物学活性的影响

目的:研究体外重组可溶性MHC Ⅰ类相关蛋白A(sMICA)对NK细胞杀伤靶细胞活性、分泌IFN-γ、增殖和凋亡的影响.方法:将重组sMICA蛋白与人外周血NK细胞相互作用过夜后,流式细胞仪检测NK细胞杀伤K562靶细胞的能力;ELISA检测培养上清IFN-γ浓度;MTS/PMS法检测sMICA对NK细胞增殖的影响;给NK细胞标记Annexin V和碘化丙啶检测凋亡情况.结果:可溶性MICA抑制NK细胞杀伤K562细胞的活性,下调IFN-γ的分泌,却对NK细胞的增殖和凋亡没有影响.结论:肿瘤细胞表面脱落的sMICA抗原可通过抑制NK细胞活性而逃逸机体的免疫监视功能.     

IFN-γ上调的单核细胞表面MHC-I类链相关分子促进NK细胞活化

目的:研究IFN-γ诱导上调表达的单核细胞MHC-I类链相关分子(MICs)分子对NK细胞的活化作用.方法:采用密度梯离离心法分离人外周血单个核细胞(PBMC),以免疫磁珠法从PBMC中特异性分选单核细胞及NK细胞,以细胞因子IFN-γ、TNF-α刺激单核细胞后,再将单核细胞与NK细胞共培养,以流式细胞术(FCM)检测NK细胞表面CD69分子及胞内IFN-γ表达,以51Cr释放试验检测NK细胞对K562细胞的杀伤效应.结果:IFN-γ上调人单核细胞表面MICs表达;IFN-γ刺激的单核细胞能促进异体NK细胞CD69及胞内IFN-γ表达,能增强NK细胞对K562细胞的杀伤效应;单核细胞的这种效应至少部分依赖于IFN-γ上调的MICs分子,因为用抗MIC抗体封闭或用细胞小室阻断细胞接触,可以明显地抑制NK细胞的活化.结论:IFN-γ上调人单核细胞表面MICs分子介导了NK细胞的活化.     

慢性 HCV 感染者外周血中 CD56＋T 细胞频数、表型和体外细胞毒功能研究

目的探讨慢性HCV感染者外周血中CD56＋T细胞的频数、表型和体外细胞毒功能特征。方法采用流式细胞术检测33例慢性HCV感染者及21例健康对照者外周血CD56＋T细胞的频数和细胞表面活化性受体NKG2C、CD16、NKp46和抑制性受体CD158a、NKG2A的表达水平;检测体外未刺激及K562细胞刺激作用下CD 56＋T细胞毒效应（ CD107a）和细胞因子分泌水平（ IFN-γ和TNF-α）,并分析上述3种CD56＋T细胞功能指标之间的关联性。结果与健康对照相比,慢性HCV感染者外周血中CD56＋T细胞在淋巴细胞中的比例明显降低（ P＝00．18）。 CD56＋T细胞表面的活化性受体 NKG2C（P＝0．015）、CD16（P＝0．036）、NKp46（P＝0．001）均有不同程度降低,而抑制性受体CD158a、NKG2A未发现有统计学意义的差异（P＞0．05）。体外未刺激情况下,慢性HCV感染者CD56＋T细胞分泌细胞因子IFN-γ和TNF -α均显著弱于健康对照组（P ＜0．0001）;在K562细胞刺激作用下,慢性HCV感染者 CD56＋T细胞CD107 a水平及分泌细胞因子IFN-γ和TNF-α均呈显著降低趋势（ P＜0．0001）,且3种功能指标表达水平密切关联（r＞0．80, P＜0．0001）。结论慢性HCV感染者CD56＋T 细胞频数降低,细胞毒能力和重要细胞因子分泌能力均明显减弱。该结果提示显著受损的CD56＋T细胞功能可能与HCV慢性持续性感染有关。     

CpG-ODN活化人NK细胞的初步研究

目的：研究D型CpG-ODN对人免疫细胞的活化效应。方法：CpG-ODN体外刺激人外周血单个核细胞(PBMC)，ELBA检测培养液IFN-α及IFN-γ的含量；RT-PCR检测PBMC中TLR9的表达水平；MTF法观察活化的NK对K562的杀伤作用。结果：CpG-ODN有效诱导PBMC分泌IFN-α和IFN-γ，增强活化的NK细胞对K562细胞的杀伤作用，且能显著上调TLR9 mRNA的表达。结论：在TLR9的介导下，CpG-ODN能有效激活NK细胞，参与机体免疫调节。     

HIV/HCV共感染患者病毒特异性CTL细胞定量研究

目的探讨病毒特异性CTL对HIVHCV共感染患者病情进展的影响机制。方法观察对象为HIVHCV共感染患者、单纯HIV感染者、单纯HCV感染者。采用四聚体技术,运用流式细胞仪检测病毒特异性CTL。前瞻性比较HIV、HCV特异性CTL在三组中的异同,并对HIVHCV共感染患者的HIV、HCV特异性CTL进行相关性分析。结果HIVHCV共感染组与单纯HIV感染组比较HIV特异性CTL,差异无显著性(P=0.586)。HIVHCV共感染组中HCV特异性CTL的百分数及绝对计数(0.37±0.29,3.52±3.79)均高于单纯HCV感染组(0.15±0.05,0.86±0.33),差异有统计学意义(P=0.001,P=0.002)。HIVHCV共感染组中的HIV特异性CTL与HCV特异性CTL存在正性线性相关(P<0.001),方程成立。并且各系数均有统计学意义,方程似然比(r2)0.761。结论HCV特异性CTL可能是HIVHCV共感染组中肝脏功能损伤加重的原因之一;HIV与HCV在同一患者存在相互影响。     

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。     

大蒜素对大鼠NK细胞肿瘤杀伤活性的影响

目的: 研究大蒜素对体外培养的大鼠NK细胞肿瘤杀伤活性的影响,并初步分析其可能机制。方法: 免疫磁珠分选法分离大鼠脾脏NK细胞,流式细胞仪检测不同浓度的大蒜素对NK细胞的增殖和凋亡的影响,ELISA检测大鼠脾脏NK细胞IFN-γ的分泌水平,乳酸脱氢酶(LDH)法检测大鼠脾脏NK细胞对小鼠淋巴瘤Yac-1细胞的杀伤活性。结果: 大蒜素对体外培养的NK细胞有明显的促进增殖和抑制NK细胞自然凋亡的作用,并能提高NK细胞分泌IFN-γ的水平和增强对Yac-1细胞的杀伤毒性,且在一定的浓度范围内呈剂量依赖性,其中30 mg/L是大蒜素的相对适宜浓度。结论: 大蒜素可能通过上调NK细胞分泌IFN-γ的水平,增强其体外肿瘤杀伤能力。     

阻断KIR2DL4(CD158d)增强NK细胞的杀伤功能

目的利用抗体阻断人原代培养的自然杀伤(NK)细胞表面的杀伤细胞免疫球蛋白样受体2DL4(KIR2DL4),抑制其与配体人白细胞抗原G(HLA-G)的结合,观察对NK细胞杀伤功能的影响。方法用免疫磁珠法分离人NK细胞并培养,流式细胞术检测所得NK细胞的纯度;流式细胞术检测NK细胞表面KIR2DL4的表达水平和人乳腺癌SK-BR-3细胞表面HLA-G的表达水平;将NK细胞与SK-BR-3细胞共培养,并加入KIR2DL4的阻断抗体,ELISA检测NK细胞分泌γ干扰素(IFN-γ)的水平,利用流式细胞术检测NK细胞表面CD107a的表达水平,以检测其脱颗粒情况。结果分离得到的人原代NK细胞纯度可达90%以上;共培养实验发现,KIR2DL4的阻断抗体可促进NK细胞分泌IFN-γ,且NK细胞表面CD107a的表达水平也明显提高,提示其脱颗粒能力增强。结论阻断KIR2DL4信号可明显促进NK细胞的杀伤功能,KIR2DL4在NK细胞杀伤靶细胞的过程中发挥抑制性作用。     

调节性T细胞对NK细胞体外杀伤乳腺癌细胞的影响

目的探讨调节性T细胞(Regulatory T cells,T-reg细胞)对NK细胞的影响及可能机制。方法流式细胞术(Flowcytometry,FCM)检测乳腺癌患者外周血中T-reg细胞、NK细胞以及T细胞亚群比例。乳酸脱氢酶(Lactate dehydrogenase,LDH)法检测NK细胞对四种乳腺癌细胞株杀伤活性。ELISA检测上清液中IFN-γ和TGF-β1含量。结果乳腺癌和健康人外周血T-reg细胞分别占CD4~+T细胞的(7.5±3.0)%和(5.1±1.5)%(P<0.01=。T-reg细胞能抑制NK细胞杀伤乳腺癌细胞,同时下调NK细胞分泌IFN-γ,上清液中TGF-β1含量随着T-reg细胞比例的增高而增加。结论T-reg细胞抑制NK细胞杀伤乳腺癌的作用,其机制与T-reg细胞分泌细胞因子TGF-β1有一定关系。     

趋化因子及受体与中国HCV/HIV合并感染相关性的研究

目的：探讨趋化因子自细胞介素8（IL-8）、干扰素诱导蛋白10（IFN-inducible 10-kdaprotein，IP-10）及趋化因子受体CCR5、CXCR3，在丙肝病毒（HCV）单纯感染，艾滋病病毒（HIV）单纯感染和HCV／HIV合并感染过程中的表达及意义。方法：采用流式细胞术，检测HCV感染组（n=21）、HIV感染组（n=14）、HCV／HIV感染组（n=28）及正常对照组（n=30）人外周血CD4^＋T淋巴细胞和CD8^＋T淋巴细胞表面CCR5、CXCR3的表达。ELISA方法检测血清趋化因子IL-8、IP-10含量。结果：HCV感染组、HIV感染组和HCV／HIV合并感染组，血清IP-10水平都明显升高，而在合并感染组水平最高；血清IL-8水平在3组亦明显升高。HIV感染组及HCV／HIV合并感染组CD4^＋T细胞表面CXCR3表达显著降低（P〈0．001），CD8^＋T细胞表面CXCR3表达显著升高（P〈0．001）；HCV感染组CD4^＋及CD8^＋T细胞表面CXCR3表达轻度升高，但差异不显著。HCV感染组及HCV／HIV合并感染组CD4^＋及CD8^＋T细胞表面CCR5表达显著降低（P〈0.001）；HIV感染组CD4^＋及CD8^＋T细胞表面CCR5表达显著升高（P〈0.001）。结论：中国HCV／HIV合并感染患者中，血清IL-8和IP-10水平都明显升高；受体CXCR3在CD4^＋T细胞表面表达降低，而在CD8^＋T细胞表面表达升高；受体CCR5在CD4^＋及CD8^＋T细胞表面表达降低，提示趋化因子及受体与HCV／HIV合并感染密切相关。     

Expansion of CD56- NK cells in chronic HCV/HIV-1 co-infection: reversion by antiviral treatment with pegylated IFNalpha and ribavirin

Co-infection with HCV and HIV-1 is a problem of increasing importance and the role of innate cellular immunity in this co-infection is incompletely understood. Here, we have observed sharply elevated numbers of CD56(-)CD16(+) perforin(low) NK cells in HCV/HIV-1 co-infected subjects on antiretroviral therapy. Interestingly, this expansion of unconventional CD56(-) NK cells rapidly reverted when HCV was suppressed by IFNalpha and ribavirin treatment, and was not seen in mono-infected control groups. In vitro experiments suggested that this effect of treatment was due to suppression of HCV viremia rather than a direct effect of IFNalpha on these cells. In contrast, the conventional CD56(+) NK cells were largely unchanged in subjects with high HCV loads, although they exhibited slightly decreased perforin expression. With delayed kinetics, the CD56(bright) immuno-regulatory NK cell subset temporarily increased to supranormal levels in response to HCV treatment. In contrast to the NK compartment, the CD1d-restricted NKT cells were severely reduced by the co-infection and not restored by treatment. Together, our data suggest that the high HCV loads in HCV/HIV-1 co-infection alter the NK cell compartment in a way not observed in HCV mono-infection.     

A VEGFR-3 Antagonist Increases IFN-γ Expression on Low Functioning NK Cells in Acute Myeloid Leukemia

Purpose

Although the importance of vascular endothelial growth factor receptor (VEGFR)-3 has been demonstrated in acute myeloid leukemia (AML), the role of VEGFR-3 in functioning natural killer (NK) cells remains largely unexplored. NK cells can destroy cancer cells by releasing the cytokine interferon (IFN)-γ, but NK cells in AML patients (AML NK cells) have low cytolytic activity. In the present study, we investigated whether lymphatic markers including VEGFR-3 are expressed on low-functioning AML NK cells and VEGFR-3 antagonist can restore expression of IFN-γ in NK cells.

Methods

Samples from 67 de novo AML patients and 34 healthy donors were analyzed for lymphatic markers expression using RT-PCR, flow cytometry, and immunostaining. For the cytotoxicity assays, K562 cells and AML NK cells were used as target and effector cells, respectively. To block VEGFR-3, MAZ51 was added to NK cells, which were then subjected to FACS analysis.

Results

Compared with NK cells from healthy donors (healthy NK cells), AML NK cells exhibited higher levels of VEGFR-3 and lower expression of IFN-γ. VEGFR-3-expressing AML NK cells were less potent than healthy NK cells in terms of killing K562 cells. The level of IFN-γ in AML NK cells was increased by VEGFR-3 antagonist treatment, indicating the functional relevance of VEGFR-3 in IFN-γ-secreting NK cells.

Conclusion

Collectively, our data suggest a relationship between VEGFR-3 and IFN-γ expression in NK cells and raise the possibility of advanced therapeutic approaches involving VEGFR-3 antagonist treatment prior to NK immune cell therapy in AML.     

Higher NK Cell IFN-γ Production is Associated with Delayed HIV Disease Progression in LTNPs

Natural killer (NK) cells are important effectors of the innate immune system that help control viral infections and tumorigenesis. However, the relationship between NK cell function and HIV disease progression remains poorly defined. In this study, we examined the function of NK cells in Chinese patients who were HIV-infected but treatment-naïve. These individuals include primary HIV-infected patients (PHIs), typical progressors (TPs), and long-term nonprogressors (LTNPs). We observed an increase of CD56^dim NK cells in PHIs, but the production of interferon-gamma (IFN-γ) and CD107a expression in PHIs were not altered compared with normal control subjects (NCs). However, the NK cells from LTNPs exhibited increased activities in IFN-γ production, CD107a expression and granzyme B change after K562 stimulation compared with NCs. Furthermore, the percentage of IFN-γ⁺CD107a^? NK cells in LTNPs was higher than that in TPs, PHIs and NCs; levels of IFN-γ production in LTNP NK cells exhibited an inverse correlation with viral loads. Similar correlations, however, were not observed in the PHI and TP groups. Taken together, these data demonstrate that enhanced NK cell function may contribute to the control of HIV infection, and increased IFN-γ secretion may be associated with delayed disease progression.     

IFN-γ production by lung NK cells is critical for the natural resistance to pulmonary metastasis of B16 melanoma in mice

NK cells are effector lymphocytes playing a critical role in the natural resistance against tumors. However, the precise mechanisms underlying NK cell-mediated natural resistance against tumor metastasis are still unrevealed. B16 cells, mouse melanoma cells, were resistant to freshly isolated NK cell-mediated killing; nevertheless, NK cells were critical for natural resistance against experimental lung metastasis of B16 cells. We found that lung metastasis was increased significantly in IFN-γ(-/-) mice but not pfp(-/-), IFN-αR(-/-), or IL-12/IL-18(-/-) mice. Interestingly, freshly isolated lung NK cells, but not spleen or liver NK cells, displayed augmented IFN-γ production after B16 inoculation. Adoptive transfer of pfp(-/-) NK cells, but not IFN-γ(-/-) NK cells, significantly decreased B16 lung metastasis in IFN-γ(-/-) and pfp/IFN-γ(-/-)mice. Lung metastases of IFN-γRDN B16 was also increased in NK cell-depleted or IFN-γ(-/-) mice, suggesting that the IFN-γ response of host cells was required in the NK cell and IFN-γ-mediated antimetastatic effect. Our results demonstrate that IFN-γ production from lung resident NK cells is a key response in the natural resistance to the experimental lung metastasis of NK cell-resistant tumor cells.     

Concomitant Effect of 2''-Deoxycoformycin on Natural Killer Cell Activity and Tumour Cell Sensitivity to Lysis in Hairy Cell Leukaemia—Discordant Effects of Alpha Interferon

The effects of 2'-deoxycoformycin (dCF) and alpha interferon (IFN-alpha) on natural killer (NK) cell-enriched fractions and hairy cell (HC) targets from three patients with HC leukaemia (HCL) were investigated. There was no significant increase in NK activity when either the HC targets or NK-enriched cells were preincubated with dCF. However, preincubation of both HC and NK cells with dCF resulted in increased NK activity. Culture of enriched NK cells with IFN-alpha enhanced their activity. However, preincubation of HC targets with this drug in the presence or absence of dCF resulted in a protective effect. Maximal NK activity towards HCL was obtained when the target tumour cells were separately precultured with dCF and the NK-enriched effectors precultured with dCF + IFN-alpha. The effect of dCF and IFN-alpha was also measured using the standard K562 cells as targets for NK activity. dCF enhanced NK activity following preculture of both effector and target K562 cells, but IFN-alpha did not reduce K562 cell susceptibility to NK lysis as it did for HC cells. Our findings suggest that (a) dCF and IFN-alpha, which are used to treat HC, could function via activation of NK cells, (b) effects on both effector and tumour target cells should be taken into account, and (c) caution should be exercised in extrapolating the effects of NK-cell activity against K562 cells to those on HC targets.     

HIV/AIDS感染者体外诱导的γδT细胞亚群的特点

目的:了解HIV/AIDS感染者外周血中γδT细胞亚群的特点以及体外诱导后γδT细胞的增殖情况和Vδ1、Vδ2亚群的变化,为γδT细胞体外扩增方法的建立打下基础。方法:流式细胞术(FCM)检测25例HIV/AIDS感染者(HIV组)和31例健康对照者(HC组)外周血中的γδT细胞、Vδ1亚群、Vδ2亚群的频率和绝对值;选择两组中各10例外周血单个核细胞(PBMC),用anti-γδTCR单克隆抗体(mAb)和IL-2在体外诱导培养14 d,在0 d、7 d、14 d分别进行细胞计数和FCM检测,分析比较γδT细胞亚群的比例和培养情况。结果:HIV组外周血中γδT细胞、Vδ2亚群百分比和绝对值都显著低于HC组,而Vδ1亚群百分比和绝对值显著高于HC组;体外诱导培养14 d时,HC组总细胞数量增加3倍,HIV组总细胞数量稍有增加;HC组的γδT细胞比例可达到80%以上,其中Vδ2亚群可以增加到65%左右,而HIV组的γδT细胞比例达35%左右,Vδ2亚群比例仅增加到17%左右。结论:HIV/AIDS感染者外周血中γδT细胞比例显著降低,Vδ1/Vδ2比值倒置;用anti-γδTCR mAb和IL-2在体外诱导HIV/AIDS感染者的Vδ2亚群扩增效果不佳,不能逆转Vδ1/Vδ2倒置现象。应进一步寻找更加有效的诱导培养方法。     

High frequency of hepatocellular carcinoma in Mongolia; association with mono-, or co-infection with hepatitis C, B, and delta viruses

To investigate the association between viral infection pattern and hepatocellular carcinoma (HCC), 292 chronic hepatitis patients, including 108 with developed HCC were screened using serological and molecular genetics methods. Viral etiology was established in 267 (91.4%), anti-HCV detected in 198 (67.8%), and HBsAg in 124 (42.5%) including 93 (74.4%) cases with HDV co-infection. HCV mono-infection predominated in both, "non-HCC" and "HCC" groups (54% and 39%, respectively) with higher frequency in the first group (P = 0.011), whereas HBV in co-infection with HDV was more frequent in HCC group (14% vs 25%, P = 0.017). Patients with HCV mono-infection were older than those with co-infection (P<0.02), had higher frequency of HCV-viraemia (82% vs 7%, P < 0.0001), and yet had significantly lower prevalence of HCC (29.6% vs. 49.1%, P = 0.003). Alpha-fetoprotein (AFP) and protein induced by vitamin K antagonist-II (PIVKA-II) were specifically elevated in 71% of HCC patients. In conclusion, although HCV monoinfection pattern predominates in Mongolia, co-infection with HBV and HDV had stronger association with HCC development at younger age. Liver tumor markers; AFP and PIVKA-II are useful tools for complex HCC-screening and clinical follow-up for chronic hepatitis patients in Mongolia.