Fas与FasL的分子及细胞生物学研究进展

Fas是Ⅰ型膜蛋白,属TNF受体家族成员,许多细胞表达Fas。而Fas配体(FasL)只在激活T淋巴细胞表达,是Ⅱ型膜蛋白,属TNF家族成员,当FasL与Fas结合时,Fas可向细胞传递“死亡信号”,细胞在数小时内凋亡,Fas-FasL介导的细胞调亡在免疫调控及免疫病理中,可能有重要作用。     

Bcl-X_L表达的上调可以保护CD40激活的人B细胞免于Fas介导的凋亡

免疫系统平衡的维持有赖于淋巴细胞成熟过程中抗原特异性克隆的选择性存活与凋亡。静止B细胞（naiveBcell）经CD40＆活可诱导Fas表达，Fas－Fas配体（FasL）的结合导致的激活B细胞的凋亡是防止抗原特异性克隆过分增殖的重要机制。而抗-Ig可部分保护B细胞免于Fas介导的凋亡，这种现象的细胞内机制还不清楚，该文研究了人扁桃体B细胞，Fas及bcl－2家族基因产物的表达，如Bcl－2，Bcl-X，Bax和Mcl-1。将人扁桃体B细胞经过Percoll不连续密度梯度离心（80％，60％，50％），分离出静止B细胞（位于60％～80％之间的细胞），经FACS分析…     

TRAIL:TNF配基家族诱导细胞凋亡的新成员

作者克隆了TNF家族的一个新成员,将其命名为TRAIL。它可以在许多细胞内快速诱导细胞凋亡,也能在大多病毒感染的原细胞内诱导细胞程序化死亡。TRAIL为一种Ⅱ型膜蛋白,其C-末端-170氨基酸与Fas配基(FasL)有30％相同,可以在包括胸腺、脾、前列腺和肺等人体组织内广泛表达。人TRAIL基因的遗传结构与TNF家族的其他成员有     

妊娠免疫耐受与器官移植

正常妊娠显示母体对同种异体胎儿的免疫耐受。最近研究表明母胎耐受与非经典HLA－I类分子HLA－G及HLA－E表达和TNF相关的凋亡诱导配体（TNF-related apoptosis-inducing ligand,TRAIL）及其受体TRAILR相互作用以及和Fas配体（FasL)表达有关。本文就这些分子在母胎耐受中的作用机制及在移植免疫中的应用前景作一综述。     

超抗原对NK细胞亚群凋亡诱导配体表达与功能的调节

目的 研究凋亡诱导配体分子在超抗原活化NK细胞CD56^bright出亚群和CD56^dim亚群上的表达规律和功能。方法以超抗原金黄色葡萄球菌肠毒素A/B（SEA/B）活化PBMC为模型,应用双重免疫荧光染色和流式细胞术分析,观察不同活化模型中凋亡诱导配体分子在NK细胞CD56^bright和CD56^dim亚群表达的变化;采用^51Cr释放实验及抗体阻断实验,观察NK细胞亚群的功能与凋亡诱导配体分子表达的关系;利用激光共聚焦显微镜,观察凋亡诱导配体分子在NK细胞杀伤相的分布。结果当超抗原浓度为0．1μg／mL时,TRAIL和TNF在NK细胞上的表达率及NK细胞杀伤活性于培养第2天时达到高峰,FasL在NK细胞上表达未见明显变化。TRAIL和TNF分子聚集于NK细胞与靶细胞的接触部位,FasL分布未见明显变化。结论超抗原SEA和SEB促进TRAIL和TNF在CD56^dim亚群表达,TRAIL和TNF可能参与NK细胞免疫突触的形成。     

妊娠免疫耐受与器官移植

正常妊娠显示母体对同种异体胎儿的免疫耐受。最近研究表明母胎耐受与非经典HLA Ⅰ类分子HLA G及HLA E表达和TNF相关的凋亡诱导配体 (TNF relatedapoptosis inducingligand ,TRAIL)及其受体TRAILR相互作用以及和Fas配体 (FasL)表达有关。本文就这些分子在母胎耐受中的作用机制及在移植免疫中的应用前景作一综述。     

TRAIL对CIA小鼠脾细胞表达Th1/Th2细胞因子的影响

 摘要：目的 观察肿瘤坏死因子相关凋亡诱导配体（Tumor Necrosis Factor Related Apoptosis Inducing Ligand , TRAIL）对胶原诱导型关节炎（Collagen-induced arthritis, CIA）小鼠的治疗效果,探讨TRAIL治疗类风湿性关节炎（Rheumatoid Arthritis, RA）的可能机制。方法 牛Ⅱ型胶原蛋白加弗氏完全佐剂免疫DBA/1J小鼠建立CIA模型,采用重组腺相关病毒AAV-TRAIL关节腔内注射进行治疗。CBA和流式细胞术检测Th1/Th2细胞因子的分泌。结果 AAV-TRAIL可改善CIA小鼠的病情,体外研究其机制发现TRAIL可抑制CIA小鼠的脾细胞分泌Th1型细胞因子,但对Th2型细胞因子没有作用。结论TRAIL对CIA小鼠的治疗作用可能和TRAIL抑制Th1型细胞因子分泌相关。     

超抗原SEB对CD8+T细胞凋亡诱导配体表达的影响

为了探讨超抗原SEB对CD8 T细胞凋亡诱导配体在细胞胞内和膜表面表达的影响,以SEB及PHA刺激PBMC,用免疫荧光染色结合三色流式细胞术,分析比较刺激前后PBMC中CD8 T细胞三种主要的凋亡诱导配体TRAIL、FasL和TNF-α在细胞胞内和膜表面表达的变化.结果表明,SEB上调FasL在CD8 T细胞胞内(34.8%至42.5%)和TRAIL在CD8 T细胞膜表面(7%至20.7%)的表达,SEB还可同时上调TNF-α在CD8 T细胞膜表面(7%至45.7%)及胞内(23.9%至88.7%)的表达.说明SEB能上调不同凋亡诱导配体在CD8 T细胞膜表面或胞内的表达,这可能是SEB影响CD8 T细胞效应功能的方式之一.     

APO—1／Fas及其配体介导超抗原SEB诱导的淋巴细胞凋亡

为了探讨超抗原诱导的淋巴细胞凋亡机制．本实验采用超抗原金黄色葡萄球菌肠毒素B（SEB）处理人外周血单个核细胞,采用流式细胞术检测细胞DNA断裂的百分率;同时动态观察了细胞表面APO-1、FasL的表达及细胞内Bcl－2蛋白的表达。结果表明,SEB不但可引起人外周血淋巴细胞凋亡,而且可诱导淋巴细胞表达APO-1和FasL。细胞凋亡的百分率与细胞表面APO-1和FasL的表达呈正相关（r＝0．71,r＝0．98）,与细胞内Bcl－2表达呈负相关（r＝－0．72）。由此可见,APO－1／Fas及其配体参与了超抗原SEB诱导的淋巴细胞凋亡。     

TNF家族新成员TRAIL及其受体与细胞凋亡

肿瘤坏死因子家族(TNF)成员在细胞凋亡的调控中发挥重要作用。TRAIL(TNF related apoptosis inducing ligand)是最近发现的TNF家族成员。在体外史验中,TRAIL能诱导多种肿瘤细胞凋亡,而正常组织细胞却对其不敏感,提示TRAIL可能成为一种新的抗肿瘤药物。TRAIL受体的发现揭示了一种新的细胞凋亡调控机制,即通过假受体竞争性抑制配体,从而诱导细胞凋亡作用。TRAIL可能与Fas系统互补而发挥作用,并且与HIV-1感染所致的T细胞减少及p53介导的DNA损伤所致细胞凋亡有关。     

CaO-MgO-P_2O_5-SiO_2-CaF_2系统自硬性玻璃的研究

为研究钙离子、镁离子在体内环境中对自硬性玻璃结晶行为的影响,为自硬性生物活性玻璃的临床应用提供依据,本文设计了CaO-P2O5-SiO2-CaF2(Ca-glass)和CaO-MgO-P2O5-SiO2-CaF2(CaMg-glass)系统玻璃并使用模拟体液(simulated body flu id,SBF)进行了研究。首先采用磷酸氢二氨[(NH4)2HPO4]/[NH4H2PO4]硬化液与Ca-glass、CaMg-glass制成硬化体,然后使用X射线衍射(XRD)、扫描电镜(SEM)、失重、力学分析等方法,研究硬化体在SBF中的结晶性、降解性和力学性能。实验结果表明,玻璃粉末与磷酸铵缓冲溶液反应形成了磷酸铵钙[(NH4)2.Ca(HPO4)2.H2O]硬化体。硬化体经过SBF浸泡,Ca-glass系统硬化体中部分磷酸铵钙转化成羟基磷灰石,而CaMg-glass系统硬化体仍然为磷酸铵钙。Ca-glass与CaMg-glass硬化体在SBF中浸泡28天分别降解19.4%和31.3%,抗压强度分别为93.14MPa和64.52MPa。镁离子的歧化作用是导致Ca-glass、CaMg-glass硬化体结晶性能、降解性能以及力学性能差别的主要原因。     

2-Perbromomethyl-2-oxazoline: a novel trifunctional initiator for the ring-opening polymerization of 2-methyl-2-oxazoline

Polymerization of 2-methyl-2-oxazoline was carried out using a trifunctional initiator, 2-perbromomethyl-2-oxazoline. The degree of polymerization (DP) of the resulting polymer was very close to the feed mole ratio of the monomer to initiator. The number-average molecular weight M?_n increased linearly with conversion, indicating the living nature of the propagating chain end. ¹H NMR and end-group analyses results are consistent with the proposal that the polymer possesses a star-shaped structure.     

Corticosteroid-interleukin 2 interactions: inhibition of binding of interleukin 2 to interleukin 2 receptors.

PHA activated human peripheral blood mononuclear cells (MNC) were incubated with human interleukin 2 (IL-2) in the absence or in the presence of 10(-6)-10(-9) M hydrocortisone (HC). HC suppressed the proliferative response of the activated MNC to highly purified human leucocyte IL-2 in a dose dependent manner. This suppression was in full accordance with an inhibition of the IL-2 binding capacity, whereby the high affinity binding sites were reduced by 85%, while the low affinity sites were less affected. The mechanism by which HC inhibits the binding of IL-2 is still unknown. Evidence is presented that HC binds only weakly to IL-2. We conclude that HC interferes with the IL-2 binding by modulating the binding and/or signal processing function of the IL-2 receptor.     

Isolation of a novel KIR2DL3-specific mAb: comparative analysis of the surface distribution and function of KIR2DL2, KIR2DL3 and KIR2DS2

In recent years an increasing number of sequences coding for new KIRs have been described. However, the limited availability of mAbs with unique KIR specificities has hindered an exhaustive assessment of their actual function, HLA-specificity, expression at the cell surface and distribution in different cell populations. In this study we report the generation of a novel mAb (ECM41) specific for KIR2DL3 molecules. By the use of cell transfectants expressing one or other KIR we show that this reagent allows discrimination of KIR2DL3 from other GL183 mAb-reactive molecules such as KIR2DL2 and KIR2DS2. Moreover we show that this novel mAb can be used to assess the surface expression and distribution of KIR2DL3 in different polyclonal NK populations and in NK cell clones. Along this line, we were able to analyze the HLA class I specificity of NK clones expressing either KIR2DL3 or KIR2DL2, two inhibitory receptors that were so far serologically undistinguishable. Finally, the combined use of GL183 and ECM41 mAbs in redirected killing assays allowed us to investigate the functional outcome of the simultaneous engagement of KIR2DL3 and KIR2DS2 in NK cell clones co-expressing KIRs that display opposite (inhibitory vs activating) function.     

13C NMR spectroscopy of 2-formamido-2-methylpropyl acrylate and poly(2-formamido-2-methylpropyl acrylate)

The synthesis and characterization of 2-formamido-2-methylpropyl acrylate (FMPA) is reported. ¹³C NMR spectra of FMPA in CDCl₃, CD₃OD, DMSO-d₆, DMF-d₇, and D₂O exhibit two pairs of lines for all seven carbon atoms at room temperature; the ratio of the two conformers varies moderately with solvent (21 : 79 to 41 : 59). The conformers are believed to involve strong internal hydrogen bonding which is not completely broken even by the addition of trifluoroacetic acid to CDCl₃ (1/1, v/v). However, the pairs of lines coalesce in turn as the temperature is raised to 120°C in DMSO-d₆. FMPA was polymerized at 35°C in DMF and CHCl₃, using a free radical initiator and the polymer was characterized by ¹³C NMR spectroscopy.     

肌肽减轻H_2O_2诱导的N2a细胞损伤

目的探究肌肽对H2O2诱导的N2a细胞损伤的保护作用及其机制。方法将N2a细胞分为对照组、损伤组(给予H2O2)和肌肽保护组(预先加入肌肽)。用相差显微镜观察了细胞形态,用免疫荧光染色和免疫印迹实验检测细胞AKT1和FAS-L的蛋白表达。结果肌肽显著增加了N2a细胞增殖能力(P0.05);与对照组比较,H2O2损伤组细胞形态发生明显改变,细胞皱缩,胞膜变厚并出现发泡现象;而肌肽保护组细胞形态较损伤组明显改善;免疫荧光染色和免疫印迹实验显示,损伤组AKT1的表达显著低于对照组,FAS-L的表达显著高于对照组。而肌肽保护组AKT1的表达显著高于对照组,FAS-L的表达显著低于对照组(P0.05)。结论肌肽能够减轻N2a细胞对H2O2诱导的细胞损伤。     

An apparent KIR2DS2-negative KIR2DL2-positive genotype discloses the novel allele KIR2DS2*00104

KIR2DS2*00104 lacks a distinctive synonymous substitution of KIR2DS2 in nucleotide 418 that affects KIR genotyping.     

Synthesis and copolymerization of macromonomers based on 2-nonyl- and 2-phenyl-2-oxazoline

Several macromonomers were prepared by cationic ring-opening polymerization of 2-nonyl- and 2-phenyl-2-oxazoline using different techniques of functionalization. Introduction of the unsaturated functional group directly via a suitable termination agent proved to be superior to the use of a phenol-functionalized initiator and to the introduction of hydroxyl end groups via hydrolysis of the reactive cationic chain end and subsequent esterification with methacryloyl chloride. The macromonomers were characterized by spectroscopic techniques as well as GPC. One of the 4-vinylbenzyl-terminated macromonomers was copolymerized with MMA in different ratios. The copolymerization parameter r₁ was determined to be 0.75. The resulting graft copolymers were characterized regarding number of grafts per chain, molar mass, and glass transition temperature.     

NDRG2对肝癌细胞HepG2凋亡的诱导作用

目的：探讨NDRG2对肝癌细胞HepG2凋亡的诱导作用。方法：用RT-PCR获取NDRG2基因。测序判断正确后，将其克隆入含绿色荧光蛋白(GFP)基因的真核表达载体pIRES2-EGFP中，并转染NDRG2表达阴性的HepG2细胞。用光镜观察转染细胞的形态变化；荧光显微镜观察NDRG2蛋白的定位；流式细胞仪分析细胞周期的改变；透射电镜进一步观察细胞超微结构的改变。结果：获得了NDRG2基因，成功地构建了pIRES2-EGFP-NDRG2真核表达载体。转染HepG2细胞后，细胞生长受抑，结构破坏并死亡。荧光显微镜观察到NDRG2在胞质中表达，流式细胞仪检测出现G1期阻滞和凋亡峰，透射电镜观察到典型的细胞凋亡特征。结论：NDRG2基因具有诱导HepG2细胞凋亡的作用，其机制有待进一步研究。     

Synthesis and polymerization of 2-cyano-2-methyltrimethylene carbonate

2-Cyano -methyltrimethylene carbonate (CMTC, 2 ) was synthesized starting from 2-methylacrolein (6), propionaldehyde (8) or 2-hydroxymethyl-2-methyl-1,3-propanediol (9). A key position in this synthesis is held by 2,2-bis(hydroxymethyl)propionitrile ( 3 ), which in a first step, is reacted — in conjunction with 2,2-dimethyl-1,3-propanediol ( 20 0) — with diphenyl carbonate ( 17 ) to result in a statistical copolycarbonate. Ring-closing depolymerization of this polymer, with a catalyst based on tin, yields in a second step the title monomer, CMTC (2), along with 2,2-dimethyltrimethylene carbonate (DTC, 1b ). Separation of the two monomers can be achieved by selective solubilization of the latter in toluene. Polymerization of CMTC is performed preferentially by using weak nucleophiles as initiators, such as Et₂AlOEt, Al(O-secBu)₃ or MgBu₂, since strong nucleophiles such as BuLi or ZnEt₂ tend to give side reactions with the cyano group. Copolymerization of CMTC with DTC results in statistical copolymers. With Et₂AlOEt as initiator copolymers with Bernoulli statistics are obtained, with a ratio of diads DTC/DTC : (DTC/CMTC + CMTC/DTC) : CMTC/CMTC equal to 1:2:1 for equimolar feed composition. With MgBu₂ as initiator and the same feed composition, a copolymer with the diad ratio 1:5:1 is obtained. Poly(CMTC) is a crystalline polymer with a melting point of 132.9°C and a glass transition temperature of 68.8 °C.