Galectin-9/ Tim-3 信号通路在HBV 感染中对机体固有免疫及适应性免疫调控的研究进展

乙型肝炎病毒(HBV)感染过程中,机体固有免疫及适应性免疫功能损伤与HBV 感染的慢性化密切相关,特别是T 细胞功能的耗竭。T 细胞免疫球蛋白黏蛋白3(Tim-3)及其配体半乳糖苷结合蛋白9(Gal-9)在包括HBV 在内的多种病毒感染所致的机体免疫功能紊乱过程中发挥着重要作用,是参与机体固有免疫及适应性免疫应答调控的重要信号通路,也是诱导T 细胞耗竭的重要负调控分子之一。本文扼要就Galectin-9/ Tim-3 信号通路在HBV 感染过程中对机体免疫功能调控的相关研究进展作综述。     

Tim-3及其配体Galectin-9与病毒感染的关系

T细胞免疫球蛋白黏蛋白3(Tim-3)基因是Tim家族成员,与其配体半乳凝素-9(Galectin-9)结合可显著抑制T细胞的活化和增殖,并调节细胞因子的表达和分泌.Tim-3/Galectin-9参与免疫反应的调节及抗病毒免疫反应,阻断此通路可促进CD8+T细胞应答和对病毒的控制.因此,Tim-3/Galectin-9通路可能与病毒感染慢性化有关.本文对Tim-3及其配体的生物学特性、功能及在病毒感染中的研究近况进行综述.     

Tim-3对人Jurkat T细胞NFAT信号通路的调控

目的利用基因过表达技术来研究关键免疫检查点Tim-3对人T淋巴细胞NFAT信号通路的调控作用。方法将NFAT-RE-Nluc、Tim-3基因编码序列制备成相应的慢病毒质粒,通过Fugene HD转染或者慢病毒介导的基因过表达技术,将NFAT-RE-Nluc和Tim-3基因编码序列导入到Jurkat T细胞中,通过萤光素酶报告基因检测系统检测细胞中的荧光信号强度。结果Tim-3和NFAT-RE-Nluc成功在人T淋巴细胞中表达,并且Tim-3成功定位到细胞膜上。Tim-3能够直接激活人T淋巴细胞的NFAT信号通路,诱导NFAT-RE-Nluc荧光素酶的表达。同时在Jurkat T细胞中,Tim-3也能够增强CD3抗体激活NFAT信号通路,诱导CD69的表达以及IL-2分泌的能力。结论成功构建了稳定表达Tim-3及NFAT-RE-Nluc报告基因的NFAT-RENluc Tim-3细胞株,为深入研究Tim-3与其配体Galectin-9或CEACAM1之间的相互作用,及筛选阻断Tim-3-Galectin-9-CEACAM1的更有效的新型免疫检查点药物提供了重要的基础。     

脓毒血症的研究机制及免疫炎症因子吸附装置北大核心CSCD

脓毒血症是机体感染后引起的一种全身性免疫应答,进展到后期可发展为脓毒血症休克、多器官衰竭甚至死亡。研究表明在脓毒血症的早期阶段,天然免疫系统被激活以便清除入侵细菌,如果控制不当,脓毒症引起细胞因子风暴特别是TNF、IL-1、IL-6等促炎因子大量释放从而加重炎症反应;到了晚期阶段由于巨噬细胞失活,抗炎因子增加则表现为免疫抑制状态。目前临床对于脓毒血症的治疗除了基础的对症用药外,还用血液净化装置以辅助缓解症状。本文通过文献检索,分析比较国内外常用免疫吸附装置的作用原理及优缺点,以期阐明免疫吸附装置在脓毒血症治疗中的前景及改进设想。     

HBV通过上调肝细胞表面Galectin-9的表达抑制NK细胞的功能

为了探讨HBV感染后Tim-3/Galectin-9信号通路对NK细胞功能的影响,我们首先利用RT-PCR和FACS法比较四种不同肝癌细胞系HepG2、HepG2-N1、HBV阳性的HepG2.2.15和HepG2-HBV细胞表面Galectin-9的表达差异,继而观察NK细胞对不同Galectin-9表达水平的靶细胞的杀伤效率和产生IFN-γ能力的变化,并采用Annexin V/PI双染法观察Galectin-9对NK细胞凋亡的影响。结果显示,HBV阳性的HepG2-HBV和HepG2.2.15细胞表面Galectin-9的表达明显高于HepG2和HepG2-N1细胞,NK细胞对高表达Galectin-9的HepG2-HBV和HepG2.2.15细胞的杀伤能力明显低于低表达Galectin-9的HepG2细胞,产生IFN-γ的能力亦明显降低。Galectin-9重组蛋白抑制NK细胞的杀伤效率并促进其发生凋亡;阻断Tim-3/Galectin-9信号可在一定程度上恢复NK细胞的功能。结果表明,HBV感染可通过诱导肝细胞表面Galectin-9的表达抑制NK细胞杀伤和IFN-γ分泌能力,并促使其发生凋亡,这可能是HBV感染易造成机体细胞免疫耐受的重要原因之一。     

我国免疫学者揭示免疫系统负调控的新机制

免疫系统在进化过程中建立了高度复杂而精细的调控机制,既防止对自身组织抗原、食物抗原、机体共生微生物和环境抗原发生有害于机体的反应,同时还要确保其在识别外来病原微生物和内在转化恶变的细胞时,能够启动免疫反应将其清除,并且不至于造成对机体自身的严重损伤。这就要求在机体的免疫调控体系中,必须有快速而高效免疫负调控机制,以保证机体内环境稳定和免疫稳态的维持。其中,免疫抑制细胞是机体免疫负调控的主要机制之一,在自身免疫性疾病、炎症反应、变态反应、移植排斥反应和肿瘤等重大疾病中均具有非常重要的作用。近年来的研究表明,FOXP3+调节性 T 细胞是机体免疫负调控的主要细胞亚群,然而,在正常生理以及特定病理环境下,FOXP3+调节性 T 细胞精细分化、抑制免疫细胞功能及其自身的功能调控机制仍不清楚。     

Tim-3 及其配体Galectin-9 在宫颈癌患者中的表达及意义

目的:通过检测宫颈癌、CIN与正常宫颈组织中Tim-3及其配体Galectin-9的表达水平,探讨Tim-3和Galectin-9与宫颈癌的关系。方法:用实时定量荧光PCR(qRT-PCR)和免疫组织化学法检测52例宫颈癌、30例宫颈上皮内瘤变患者和25例正常宫颈组织中Tim-3和Galectin-9的表达,并结合临床病理学资料对实验数据进行统计学分析。结果:①qPT-PCR检测Tim-3和Galectin-9的表达显示,其mRNA水平宫颈癌组高于CIN组和正常组(P0.05),CIN组高于正常组(P0.05)。②Tim-3和Galectin-9 mRNA水平与FIGO分期(P0.05)、分化程度(P0.05)和有无淋巴结转移(P0.05)均明显相关。③免疫组化结果显示宫颈癌组织中Tim-3和Galectin-9在癌巢中呈阳性表达,其MOD值明显高于CIN组织及正常宫颈组织,差异有统计学意义(P0.01)。④宫颈癌组织中Tim-3和Galectin-9的MOD值与FIGO分期(P0.05)、病理分型(P0.05)、分化程度(P0.05)和有无淋巴结转移(P0.05)均明显相关。结论:Tim-3和Galectin-9的mRNA水平和MOD值在宫颈癌中升高,并与宫颈癌的FIGO分期、分化程度和有无淋巴结转移密切相关。     

锌指蛋白A20对Toll样受体信号途径的负反馈调控及其对机体的保护作用

Toll样受体（TLR）能够识别病原体,并在病原体入侵机体的早期启动固有免疫,促进免疫细胞成熟分化及调节免疫应答,触发炎症反应。脂多糖（LPS）激活TLR4的信号转导通路后导致NF—κB和JNK／SAPK激活,使炎症因子大量表达,导致全身炎症反应和多器官功能衰竭的发生。A20作为一种NF—κB依赖性表达的胞质蛋自,对NF—κB活性有负反馈调控作用,参与了体内炎症反应的调节和凋亡抑制,对机体起到保护作用。     

Galectin-9(Tim-3L)显著减弱小鼠移植排斥

目的 探究Galectin-9(即T cell immunoglobulin domain and mucin domain protein-3 ligand,Tim-3L)的真核定位与功能,及其对同种异基因排斥反应的影响.方法 PCR扩增Galectin-9片段,插入到pEGFP-N1质粒,转染中国仓鼠卵巢癌细胞系(CHO)行G418筛选,分选增强型绿色荧光蛋白(EGFP)阳性细胞.免疫组化检测Galectin-9的表达,Alamar Blue法检测稳定转染Galectin-9的CHO细胞及其新鲜培养上清对脾细胞增殖的影响,ELISA检测IL-2水平.给予BALB/c→C57BL/6心脏移植受鼠Galectin-9蛋白100μg×7 d.结果 Galectin-9表达于细胞浆,稳定转染Galectin-9-EGFP的CHO细胞上清抑制淋巴细胞增殖和IL-2的产生.上述效应可被Tim-3-Fc融合蛋白逆转.Galectin-9干预的心脏移植物中位生存时间明显延长[(22.7±1.2)d,(7.2±0.4)d)].结论 真核细胞中Galectin-9可通过分泌形式负调节同种异基因免疫;Galectin-9有望成为新型的抗排斥药物.     

MDSC对免疫系统的抑制机制

机体的免疫系统是一个复杂的网络调控系统,由固有免疫和适应性免疫组成,其中包括了固有免疫细胞、抗原递呈细胞、适应性免疫细胞等之间的相助作用和调节。越来越多的证据表明一群骨髓来源的具有CD11b和Gr-1标志的抑制性细胞在各种感染、肿瘤、急慢性炎症等疾病中大量存在,并且负向调节机体的免疫功能。这就是具有负向调节机体免疫反应的髓系抑制性细胞(MDSC),近年来被广泛研究。MDSC是免疫系统调节机体免疫反应的一群独特的细胞群体,可以对多种免疫细胞通过多种不同的机制发挥免疫抑制功能,从而导致机体固有免疫和适应性免疫功能的低下,促进疾病的发展和恶化。本文着重就MDSC对参与机体免疫反应的几种炎性细胞的抑制     

雷公藤甲素抗肿瘤血管新生的研究进展（英文）

雷公藤甲素(triptolide,TPL)是从中草药雷公藤中提取的一种有效活性物质,已被用来治疗多种疾病,包括系统性红斑狼疮,类风湿性关节炎,肾病综合征等,TPL甚至有很强的抑制肿瘤的活性。近些年的研究显示,TPL具有抗血管新生的能力,TPL不仅可以抑制肿瘤的增殖,诱导细胞的凋亡,还可以抑制肿瘤的转移,可以增加其它化疗药物的抗肿瘤活性。本综述将讨论TPL在抗肿瘤血管新生方面的研究进展,以及初步探讨其潜在的作用机制。     

Changes in activity of neutral proteases in tissues of ground squirrels in the dynamics of hibernation

Total activities of neutral proteases in the cerebral, hepatic, and myocardial tissues of ground squirrel vary during hibernation: in autumn (before hibernation) activities of the enzymes in the brain and myocardium start increasing, while in the liver they do not change. A common feature for all tissues is minimum activity of active neutral proteases in the middle of hibernation month 1 bout, while the maximum activity is recorded before awakening. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 9, pp. 278–280, September, 2008     

Kinetics of decline of maternal measles virus-neutralizing antibodies in sera of infants in France in 2006

The optimal age for measles vaccination is an important health issue, since maternal antibodies may neutralize the vaccine antigen before a specific immune response develops, while delaying vaccination may increase the risk of complicated diseases in infants. However, measles vaccination impacts the duration of protection afforded by transplacental transfer of maternal antibodies: vaccination-induced maternal antibodies disappear faster than disease-induced antibodies. In order to maintain protection against measles in infants, it is important to monitor the dynamics of this phenomenon in vaccinated populations. To assess the current situation in France, a multicenter, prospective seroepidemiological study was conducted in seven French hospitals between October 2005 and January 2007. Maternal measles antibody concentrations from 348 infants 0 to 15 months old were measured using the plaque reduction neutralization assay. Geometric mean concentrations and the percentage of infants with maternal measles antibody concentrations above the protection threshold (≥120 mIU/ml) were assessed according to age. Results show that after more than 20 years of routine measles vaccination in France, maternal measles-neutralizing antibodies decrease dramatically in French infants by 6 months of age, from 1,740 mIU/ml for infants 0 to 1 month old to 223 mIU/ml for infants 5 to 6 months old, and that 90% of infants are not protected against measles after 6 months of age. Infant protection against measles could be optimized both by increasing herd immunity through an increased vaccine coverage and by lowering the age of routine vaccination from 12 to 9 months.     

Effect of vitamin C in reducing the toxicity of endosulfan in liver in rabbits

In this study, the effect of endosulfan, an organochlorine pesticide, and the ameliorating effect of vitamin C on the livers of New Zealand white rabbits were studied. Livers of the rabbits were examined grossly and histopathologically, and caspase-3 activity was detected by immunohistochemical methods. A total of twenty-four rabbits were divided into four groups (n=6). Rabbits in Group I (END) were daily given a sublethal dose of endosulfan (1 mg/kg bw) in corn oil by oral gavage for 6 weeks. Group II (END+C) received the same dose of endosulfan and additionally Vit C (20 mg/kg bw) every other day during this period. Group III (OIL+C) received corn oil daily by oral gavage and vitamin C every other day for 6 weeks. Group IV (OIL), the control group, received only corn oil daily, by oral gavage throughout the experiment. The concentration of α-endosulfan in the END group was higher in livers (0.102±0.012 ppb) than the β-endosulfan (0.072±0.001 ppb). Decreased accumulation of α and β endosulfan was observed in the END+C group (0.025±0.003 and 0.016±0.002 ppb, respectively) (p<0.0001). The most prominent gross findings at the necropsy were seen in the END group, in which swollen and pale livers were commonly observed. Hemorrhages, degenerations, necrosis, and in some rabbits bile duct hyperplasia were the marked histopathological findings of the END group. Caspase-3 positive reaction was more severe in this group than in the others. An ameliorating effect of Vit C on gross, histopathological and immunohistochemical findings was observed in the END+C group. The results revealed that endosulfan is highly toxic for rabbit livers. However, toxicity was decreased by Vit C treatment, which reduced the accumulation of endosulfan in livers four-fold.