树突状细胞和抗原负载树突状细胞在肿瘤模型鼠体内的分布和形态学观察

目的:研究体外培养的小鼠树突状细胞(dentritic cells,DCs)和抗原负载树突状细胞在肿瘤模型鼠体内的分布和形态,为肿瘤的生物学治疗提供形态学基础.方法:分离和培养DC,制备B16黑色素瘤细胞抗原,进行共培养,即为抗原负载的DC,Brdu标记DC和抗原负载的DC,建立B16黑色素瘤小鼠模型,于瘤周围皮下注射Brdu标记的DC和抗原负载的DC.应用光镜、免疫组化方法和透射电镜观察DC和抗原负载DC在肿瘤模型鼠体内的分布和形态.结果:免疫组化染色显示Brdu标记的抗原负载DC与DC比较,体积较大.实验组Brdu标记的DC和抗原负载DC分布的数密度和面密度,分别与对照组比较,有显著差异(P＜0.01).电镜下抗原负载DC细胞与DC比较体积较大,核有切迹,细胞表面的突起较粗大弯曲,形态较成熟.结论:抗原负载DC比DC更易集聚于肿瘤组织周围,推测抗原负载DC比Dc可能诱导抗肿瘤效应更强.     

p53转染黑色素瘤细胞修饰的树突状细胞疫苗体外抗肿瘤作用的研究

利用野生型p53质粒转染黑色素瘤B16细胞,反复冻融法提取p53修饰的肿瘤抗原(p53-Ag),将抗原体外冲击同基因小鼠骨髓来源的树突状细胞(dendritic cells,DC)制备特异性DC肿瘤疫苗;观察DC诱导的淋巴细胞增殖反应和细胞毒性T淋巴细胞(cytotoxic T lymphocytes,CTL)对黑色素瘤细胞的细胞毒效应,分析其诱导肿瘤抗原特异性免疫应答的机制。结果显示,p53-肿瘤抗原冲击的DC可显著刺激淋巴细胞增殖,其诱导的CTL效应对肿瘤细胞也有很好的杀伤效果。     

透明质酸介导的树突状细胞肿瘤抗原提呈效应的形态学研究

目的:探讨透明质酸对树突状细胞肿瘤抗原提呈效应的调节作用.方法:建立B16黑色素瘤小鼠模型;用GM-CSF和IL-4诱导扩增小鼠骨髓来源的树突状细胞,并用透明质酸孵育,Brdu标记;经肿瘤周围皮下回输,以普通DC、生理盐水为对照组;测量瘤体积,计算抑瘤率.光镜、透射电镜、免疫组织化学法观察HA-DC于肿瘤局部组织和淋巴结内的分布和形态学特征.结果:HA-DC细胞组的抑瘤作用强于DC细胞组(P＜0.05);HA-DC细胞主要分布于肿瘤周围和淋巴结副皮质区,透射电镜观察可见HA-DC组肿瘤周围组织中有大量树突状细胞和淋巴细胞浸润,相互有膜接触,淋巴细胞以突起深入肿瘤细胞,并与其接触、融合,肿瘤细胞发生凋亡.结论:DC负载透明质酸后可以有效激活和扩增淋巴细胞,增强机体肿瘤特异性CTL效应.     

体外培养的小鼠抗原负载树突状细胞的形态学特征

目的:研究体外培养的小鼠抗原负载树突状细胞(dentritic cells,DCs)的形态学特征,为肿瘤的生物学治疗提供形态学基础.方法:分离和培养DC,制备B16黑色素瘤细胞抗原,进行共培养,即为抗原负栽的DC.建立B16黑色素瘸小鼠模型,于瘤周围皮下注射抗原负载的DC.应用光镜、免疫组化方法和透射电镜观察抗原负载DC的形态学特征.结果:培养的抗原负载DC与DC比较,体积较大,表面突起较粗大且弯曲.免疫组化染色显示抗原负载树突状细胞主要分布于肿瘤周围皮肤的乳头层、网织层和肿瘤周围,于局域淋巴结的被膜下窦和副皮质区有散在分布.电镜下抗原负载DC细胞体积较大,核有切迹,细胞表面的突起,与肿瘤细胞和淋巴细胞接触密切.结论:抗原负载DC表现出比一般树突状细胞功能更加活跃的形态特征,冻融法全细胞来源的肿瘤抗原负载DC可以获得理想的DC疫苗.     

肿瘤抗原基因转染的DC疫苗研究进展

树突状细胞是机体内最重要、功能最强的专职抗原递呈细胞,是抗肿瘤免疫的最好佐剂。将不同形式肿瘤抗原负载的DC制成疫苗,可以在体内诱导特异性杀伤性T细胞（CTL）的生成,激发人体有效的特异性抗肿瘤免疫功能。其中肿瘤抗原原因转当的DC疫苗具有很多独特的优点,可望作为一种新型肿瘤疫苗用于肿瘤的防治。本文主要就其作用特点、体内应用的可行性及抗肿瘤作用效果的实验研究进展等方面作一综述。     

抗原负载DCs诱导的CIK细胞对B16黑色素瘤抑制作用的形态学观察

目的:探讨抗原负载树突状细胞(dentritic cells,DCs)诱导的CIK(cytokine induced killer)细胞对B16黑色素瘤的抑瘤作用。方法:分离、培养DC和CIK细胞,取部分DC进行肿瘤抗原负载,将其与CIK细胞按1:10的比例共培养3d,即为抗原负载的DC-CIK。建立B16黑色素瘤小鼠模型,分别于瘤周围皮下注射经Brdu标记的CIK、DC-CIK、抗原负载DC-CIK。按注射细胞进行分组,测量注射前后各组小鼠的瘤体积,计算抑瘤率,比较其抑瘤作用。应用免疫组化方法和透射电镜观察抗原负载DC-CIK细胞在皮肤中的分布及杀伤肿瘤细胞的形态学表现。结果:抗原负载DC诱导的CIK(细胞组抑瘤率(86.57%)高于CIK细胞组(33.34%,P<0.05)和DC-CIK细胞组(61.08%,P<0.05);光镜下抗原负载DC-CIK细胞主要分布在皮下组织,癌组织周围,特别是癌巢周边。透射电镜下抗原负载DC-CIK细胞体积大,核有切迹,细胞质内细胞器丰富,粗面内质网扩张。细胞表面有突起,与肿瘤细胞密切接触。大量肿瘤细胞凋亡、坏死。结论:CIK细胞经抗原负载DC诱导后抑瘤作用明显强于单纯CIK细胞和DC-CIK细胞。     

PEG10基因转染的树突状细胞疫苗对肝癌细胞的杀伤实验研究

目的:研究印记基因PEG10修饰的树突状细胞(DC)疫苗对肝癌细胞的杀伤效应,为肝癌的治疗提供新的策略。方法:将重组PEG10腺病毒rAd-PEG10感染HLA-A2阳性的人外周血来源的DC,制备PEG10基因修饰的DC疫苗,并在体外刺激HLA-A2阳性限制性的单个核细胞,酶联免疫斑点试验(Enzyme Linked Immunospot Assay, ELISPOT)和标准⁵¹Cr释放试验分别检测PEG10腺病毒感染的DC所诱导的特异性CTL活性,并检测对HLA-A2阳性的HepG2肝癌细胞的杀伤作用。结果:成功制备了PEG10基因修饰的树突状细胞(DC)疫苗,并在体外能有效诱导抗原特异性CTL效应,对HepG2肝癌细胞有明显的杀伤毒性。结论:PEG10基因修饰的树突状细胞能有效激发出特异性CTL应答,并对HepG2肝癌细胞有明显的杀伤毒性,为肝癌治疗提供了新思路。     

CpG-ODN2216致敏的单核细胞培养上清对HBV相关性肝癌病人的树突状细胞表型和功能的影响

目的:研究CpG-ODN2216致敏的外周血单核细胞(PBMC)培养上清液对HBV相关性肝癌病人的树突状细胞(DC)成熟与功能的影响,寻求一种增强DC疫苗效果的方法。方法:从9例HBV相关性肝癌患者PBMC中诱导出未成熟的单核细胞来源的DC(MoDC),经HBV核心抗原(HBcAg)负载后,用CpG-ODN2216刺激的PBMC上清液、“细胞因子鸡尾酒(IL-1β、IL-6、TNF-α和PGE2)”以及两者的联合作用促进MoDC的进一步成熟,检测MoDC表型和功能;选择其中5例HLA-A2 病人,用成熟MoDC诱导自身T细胞产生HBV特异性CD8 的细胞毒性T淋巴细胞(CTL)。结果:用细胞因子鸡尾酒和CpG-ODN2216刺激的PBMC上清液联合作用可明显增强MoDC表面的CD80、CD83和CD1a表达,其对HBcAg负载的MoDC促成熟作用大于单独用细胞因子鸡尾酒或单独用CpG-ODN2216刺激PBMC的上清液。联合作用促进MoDC分泌IL-12和IL-10的能力明显强于单独应用PBMC上清液或细胞因子鸡尾酒,其刺激自体T细胞分泌IFN-γ、TNF-α、IL-6的能力也明显增高。联合作用促成熟的MoDC诱导HLA-A2 病人的自体T细胞产生HBVcore18-27特异性CD8 CTL的频率明显高于细胞因子鸡尾酒单独促成熟的MoDC。结论:CpG-ODN2216刺激PBMC的上清液和细胞因子鸡尾酒联合作用可以明显促进HBcAg负载的HBV相关性肝癌病人的MoDC成熟,增强MoDC分泌细胞因子、刺激自体特异性T淋巴细胞应答、诱导HBV特异性细胞毒性T细胞的能力。为提高HBV特异性树突状细胞疫苗的效果提供了一种可行方案。     

烟曲霉抗原Asp f16HLA-A*0201限制性的CD8+CTL抗原表位生物信息学预测与实验室鉴定

目的 预测与鉴定烟曲霉抗原Asp f16的HLA-A *0201限制性CD8+细胞毒性T细胞(CTL)抗原表位.方法 以国人常见的HLA-A*0201位点为靶点,依据生物信息学软件扫描烟曲霉特异性抗原Asp f16的全部427个氨基酸序列.使用HLA-A *0201转基因小鼠制备骨髓来源的树突状细胞(DC)和CTL.流式细胞仪技术检测DC表面MHC Ⅱ类抗原,CD80,CD86和CD11c的表达来验证其是否成熟.ELISPOT试验检测烟曲霉抗原多肽特异性CTL产生的细胞因子IFN-γ.四聚体(Tetramer)试验证实烟曲霉特异性CTL与抗原肽,HLA-A*0201分子复合体的亲和性.结果 根据与MHC I类分子结合的半衰期评分,选择了3个HLA-A*0201限制性抗原表位.流式细胞仪分析示成熟DC高表达HLA Ⅱ类抗原,CD80,CD86和CD11c.Tetramer试验证实烟曲霉特异性T细胞受体与抗原肽,HLA-A*0201分子复合体的高亲和性.ELISPOT实验结果 表明烟曲霉抗原肽体外可以活化CD8+CTL,被负载了抗原肽的DC刺激活化后可以产生IFN-γ.结论 本研究成功鉴定烟曲霉抗原Asp f16的HLA-A*0201限制性CD8+CTL表位,可作为疫苗设计的候选表位,为进一步研发新型抗烟曲霉疫苗提供参考.     

Hs-exosomes致敏树突状细胞介导的抗卵巢癌免疫治疗的实验研究

目的检测卵巢癌细胞的外排小体Hs-exosomes致敏树突状细胞DC诱导T淋巴细胞CTL特异性杀伤卵巢癌细胞的能力。方法:分离卵巢癌细胞株2780释放的Hs-exosomes,将其致敏DC并与T淋巴细胞共培养,检测CTL体外细胞毒活性。结果:Hs-exosomes致敏DC激活CTL的抗肿瘤能力显著高于未致敏DC组。结论:2780细胞释放的Hs-exosomes致敏DC激活T淋巴细胞对肿瘤具有很强的杀伤作用。     

B7家族的新成员

T细胞的活化需要共刺激分子和其受体及特异性抗原与T细胞受体的双信号作用。B7家族成员是重要的共刺激分子,除B7－1和B7－2,新近又发现了一些新成员：B7RP－1（又名B7h,GL50或ICOSL）为鼠ICOS（inducible costimulator,CD28家族的第三位成员）的配体,其人的同源物命名为B7－2（也称为GL50或ICOSL）,它对TG细胞生长及细胞因子产生的共刺激作用已明显,B7－H1（也称PD－1L）,B7H3是一类不与ICOS结合的B7家族新成员。现已证实。现已证实,这些分子与其受体之间的作用在T细胞增殖及发挥效应中扮演重要角色,它们在许多疾病中的作用也引起学者的普遍关注。     

家兔BMP7基因的克隆及其生物信息学分析

在对已知部分编码序列(CDS)进行分析的基础上, 采用RT-PCR分步扩增以及RACE方法, 对家兔BMP7基因3′和5′末端未知序列进行了克隆与生物信息学分析。测序结果综合分析表明, 所获序列共计1 654 bp, 包括家兔BMP7近全长前肽、全长成熟肽CDS及3′非翻译序列(3′UTR), 将已有的序列向5′和3′端分别延伸了395 bp和628 bp。序列对比表明, 克隆的家兔BMP7 CDS部分与人、小鼠的对应序列的同源性分别为91.89%和89.32%, 预测的氨基酸序列同源性分别为96.51%和96.01%。家兔BMP7 3′UTR长446 bp, 与人、小鼠对应序列同源性分别为57.38%和45.57%; 具有2个转录终止信号位点。推测家兔BMP7成熟蛋白有BMPs特有的7个位置固定的半胱氨酸残基和TGF-β家族指纹。家兔BMP7 3′UTR区转录终止信号的可选择性可能与基因转录后调控有关。     

7-DEAZAPURIN-2,6-DIAMINE AND 7-DEAZAGUANINE: SYNTHESIS AND PROPERTY OF 7-SUBSTITUTED NUCLEOSIDES AND OLIGONUCLEOTIDES

The synthesis of 7-substituted 7-deazaguanine and 7-deazaadenine ribonucleosides 1–2, the incorporation of 3a–d into oligonucleotides, and the stability of the corresponding duplexes and base discrimination are described. The pK_a values of 3–4 are determined.     

Synthesis of 7-trifluoromethyl-7-deazapurine ribonucleoside analogs and their monophosphate prodrugs

Abstract

Novel 7-trifluoromethyl-7-deazapurine ribonucleoside analogs (13a-c) and their Protides (15a-c) were successfully synthesized from ribolactol or 1-α-bromo-ribose derivatives using Silyl-Hilbert-Johnson or nucleobase-anion substitution reactions followed by key aromatic trifluoromethyl substitution. Newly prepared compounds were evaluated against a panel of RNA viruses, including HCV, Ebola or Zika viruses.     

7-SUBSTITUTED 8-AZA-7-DEAZAPURINES AND 2,8-DIAZA-7-DEAZA-PURINES: SYNTHESIS OF NUCLEOSIDES AND OLIGONUCLEOTIDES

7-Substituted 8-aza-7-deazaadenosines 1a–e were synthesized by Sonogashira cross coupling from the corresponding 7-iodo nucleoside in 36–79% yields. Starting from 7-bromo (or 7-iodo)-8-aza-7-deazaadenine, 2a,b were obtained by acid-catalyzed glycosylation followed by deprotection in 53 and 35% yields, repectively. Compounds 2b was applied to cross coupling reaction to give 2c-d in 34–95% yield. Compounds 2a and 4b were further transformed to the phosphoramidites 5 and 6b in 9 and 49% overall yields, which were incorporated into oligonucleotides.     

Simultaneous determination of coumarin, 7-hydroxycoumarin and 7-hydroxycoumarin glucuronide in human serum and plasma by high-performance liquid chromatography

A HPLC method was developed for the determination of the metabolites of coumarin and 7-hydroxycoumarin in plasma and serum. Separation was based on gradient elution of 7-hydroxycoumarin glucuronide, 7-hydroxycoumarin, coumarin and finally 4-hydroxycoumarin (which is used as an internal standard). Standards, prepared in plasma or serum, and samples were treated with trichloroacetic acid, mixed and centrifuged. The supernatant was removed and analyzed by reversed-phase high-performance liquid chromatography on a C₁₈ column. The limit of detection was 50 ng/ml for 7-hydroxycoumarin and 200 ng/ml for coumarin and 7-hydroxycoumarin glucuronide. The linear range was 0.5–100 μg/ml for each of the analytes. The percentage relative standard deviation about the mean measured concentrations were all below 10%. There was no statistical difference between the standard curves prepared in plasma or serum. The method developed was applied to the determination of each of the three compounds in serum, after the administration of 7-hydroxycoumarin, and in plasma after the administration of coumarin. The concentrations of total 7-hydroxycoumarin in the serum samples were also determined by another HPLC method and the results were compared. There was no statistical difference between the results determined.     

One step engineering of T7-expression strains for protein production: increasing the host-range of the T7-expression system

The T7-expression system has been very useful for protein expression in Escherichia coli. However, it is often desirable to over-express proteins in species other than E. coli. Here, we constructed an inducible broad-host-range T7-expression transposon, which allows simple one-step construction of T7-expression strains in various species, providing the option to over-express proteins of interest in a broader host-range. This transposon contains the T7 RNA polymerase driven by the lacUV5 promoter, which is repressed by the lac-repressor. Leaky expression is prevented by the presence of T7-lysozyme on this construct. The complete T7-expression system is flanked by mariner transposon repeats of the suicidal R6Kgammaori plasmid, pBT20-Deltabla. Stable integration of the whole system is possible by a one-step selection for a Flp-excisable Gm(R)-marker. We showed the engineering of E. coli, Pseudomonas aeruginosa, Erwinia carotovora, Salmonella choleraesuis, Agrobacterium tumefaciens, and Chromobacterium violaceum strains with this construct and demonstrated the expression of the Burkholderia pseudomallei Asd protein in these hosts, by induction with isopropyl-beta-d-thiogalactopyranoside (IPTG).     

Microbial degradation of 7-ketocholesterol

7-Ketocholesterol (7KC) is an oxidized derivative of cholesterol suspected to be involved in the pathogenesis of atherosclerosis and possibly Alzheimer’s disease. While some oxysterols are important biological mediators, 7KC is generally cytotoxic and interferes with cellular homeostasis. Despite recent interest in preventing the accumulation of 7KC in a variety of matrices to avoid adverse biological effects, its microbial degradation has not been previously addressed in the peer-reviewed literature. Thus, the rate and extent of biodegradation of this oxysterol was investigated to bridge this gap. A wide variety of bacteria isolated from soil or activated sludge, including Proteobacterium Y-134, Sphingomonas sp. JEM-1, Nocardia nova, Rhodococcus sp. RHA1, and Pseduomonas aeruginosa, utilized 7KC as a sole carbon and energy source, resulting in its mineralization. Nocardia nova, which is known to produce biosurfactants, was the fastest degrader. This study supports the notion that microbial catabolic enzymes could be exploited to control 7KC levels in potential biotechnological applications for agricultural, environmental, or medical use.