人新型干扰素κ的基因克隆、表达、纯化及其抗病毒活性的初步研究

目的制备人干扰素κ(hIFNκ)并初步研究其生物学活性。方法克隆hIFNκ的cDNA并根据大肠埃希菌的密码子偏好性人工合成了hIFNκ基因,在大肠埃希菌DH5α中高效表达、纯化后测定了rhIFNκ的多种生物学活性,包括抗病毒活性、抗细胞增殖活性、种属特异性以及NK细胞调节活性。结果成功地获得了高纯度的rhIFNκ,纯度在90%以上。利用WISHVSV系统检测rhIFNκ的抗病毒活力为2.0×106IU/mg。与rhIFNα2b的比较发现,rhIFNκ无论在抗病毒活性、细胞生长抑制,还是在促NK细胞活性方面均弱于前者。结论rhIFNκ在不同种属来源细胞上的抗病毒活性因种属来源而异,不同的病毒对rhIFNκ的敏感性是不同的。     

新型重组人IFN-λ2的高效表达、纯化与抗病毒活性研究

目的在大肠埃希菌中高效表达重组人干扰素λ2(rhIFNλ2),并对其抗病毒活性进行初步研究。方法根据大肠埃希菌的偏爱密码子人工设计合成人干扰素λ2(hIFNλ2)的高表达基因,将其克隆到原核表达载体pBV220,在大肠埃希菌中进行表达,表达产物经变性、复性、阳离子交换层析及分子筛层析纯化,测定其抗病毒活性、种属特异性及抗HBV活性。结果在大肠埃希菌表达的目的蛋白占细胞总蛋白量的15%左右,纯化后的纯度达到90%以上,在WISH细胞上抗VSV活性约为1.5×106IU/mg。与rhIFNα2b比较,表达产物在非灵长类细胞上的抗病毒活性较在灵长类细胞上弱,目的蛋白在HepG2.2.15细胞上表现有与rhIFNα2b相似的抗HBV活性。结论hIFNλ2可以在大肠埃希菌内实现高效表达,表达产物具有抗病毒活性,有与rhIFNα2b相似的抗HBV活性,本型IFN有较严格的种属特异性。     

重组人干扰素Epsilon的表达纯化及生物学性质研究

目的表达纯化一种新型重组人干扰素Epsilon(rhIFNε155ser),并对它的生物学特性进行初步研究。方法人工合成rhIFNε155ser的全基因序列,并按照大肠埃希菌密码子嗜性作适当改造,然后构建到原核表达载体pBV220,在大肠埃希菌DH5α中表达。将表达的包涵体蛋白纯化复性后,对最终产物的抗病毒活性、细胞生长抑制活性和NK细胞刺激活性进行鉴定。同时,利用芯片技术,从基因的水平对rhIFNε155ser的生物机制进行初步的了解。结果rhIFNε155ser以包涵体的形式表达,经纯化蛋白纯度可达95%。复性后rhIFNε155ser在WISH抗VSV系统中的抗病毒活性可达6×105IU/mg。在100～1000pg/ml下rhIFNε155ser具有剂量依赖性的抗增殖活性,而NK细胞刺激活性无剂量依赖性。基因芯片扫描发现,22278个位点中,有283个基因显著上调,另外1894个显著下降。结论成功地表达了rhIFNε155ser,发现此IFN具有一定的抗病毒、抗增殖和NK细胞刺激活性。芯片技术可进一步拓展对IFN的功能研究。     

hIEN-λ1(hIL-29)基因及在COS-7细胞中瞬时表达和抗病毒效应

目的克隆hIFN-λ1基因,构建pcDNA3.1 A-IFN-λ1表达质粒,并在真核细胞中获得表达,以进一步研究rhIFN-λ1的生物学特性.方法采用RT-PCR法从病毒诱导的A549细胞mRNA中克隆hIFN-λ1基因,并重组于pcDNA3.1A真核表达载体上.结果经双酶切和PCR鉴定及DNA序列分析,发现所克隆的基因与GenBank公布的序列一致,并在COS-7细胞中获得了有效瞬时表达.结论成功克隆了hIFN-λ1基因,并成功地获得了瞬时表达,其rhIFN-λ1表达产物具有抗病毒活性.     

hIFN-λ1（hIL-29）基因及在COS-7细胞中瞬时表达和抗病毒效应

目的：克隆hIFN-λ1基因，构建pcDNA．3．IA-IFN—λ1表达质粒，并在真核细胞中获得表达，以进一步研究rhIFN-λ1的生物学特性。方法：采用RT-PCR法从病毒诱导的A549细胞mRNA中克隆hIFN-λ1基因，并重组于pcDNA3．1A真核表达载体上。结果：经双酶切和PCR鉴定及DNA序列分析，发现所克隆的基因与GenBank公布的序列一致，并在COS-7细胞中获得了有效瞬时表达。结论：成功克隆了hIFN-λ1基因，并成功地获得了瞬时表达，其rhIFN-λ1表达产物具有抗病毒活性。     

人Epsilon干扰素在CHO细胞中的表达及生物学活性的研究

目的 为了研究新发现的人epsilon干扰素（hIFN-ε）的生物学活性，我们通过RT-PCR克隆了hIFN-ε基因，并构建pcDNA3．1／myc-his（-）A-hIFN-ε（以下简称pcDNA3-1A-hIFN-ε）的真核表达载体，在CHO细胞中表达，并研究真核细胞重组表达的rhIFN-ε的生物学活性。方法 用TNF-α刺激人宫颈癌HeLa细胞，抽提总RNA，经RT-PCR获得全长cDNA，与pcDNA3．1／myc-his（-）A真核表达载体连接，构建重组体pcDNA3．1A-hIFN-ε并在CHO细胞中进行表达，采用微量细胞病变抑制试验研究表达产物中的rhIFN-ε对多种病毒的抗病毒活性；MTT法检测其对A375、HeLa和A549细胞的生长影响，并通过在Wish、HeLa、A375细胞中诱导MxA抗病毒蛋白的产生研究hIFN-ε的抗病毒机制。结果 经PCR和限制性酶切鉴定以及DNA测序，结果表明已经成功构建了重组体pcDNA3．1A-hIFN-ε，并在CHO细胞中稳定表达了rhIFN-ε蛋白，该蛋白具有抗HSV-I、PolioV、Ad3和VSV病毒的作用，能够抑制HeLa、A375、A549细胞的生长，刺激Wish、HeLa、A375细胞产生MxA蛋白。结论 本研究成功地构建了pcDNA3．1A-hIFN-ε真核表达载体并在CHO细胞中获得稳定表达，证明了ddFN．￡蛋白具有抗病毒和抗增殖活性，其抗病毒效应的分子机理可能与诱导细胞产生MxA抗病毒蛋白有关，为今后研究rhIFN-ε的生物学功能和基因重组药物研制及其开展基因治疗奠定了基础。     

新型基因工程干扰素受体结合域的改造及其生物活性测定

目的 改造干扰素功能结合域，以提高干扰素的生物学活性。方法 在新型基因工程干扰素（IFNα1c/86D)AB环内通过点突变技术引入2个独立酶切位点EcoRV和EstEⅡ，用聚合酶链反应（PCR）技术在干扰素cDNA水平对母体干扰素LoopAB的31位甲硫氨酸换成天冬氨酸（M－D），32位天冬氨酸换成脯氨酸（D－P），将重组基因在大肠埃希菌中表达，用滤泡口炎病毒（VSV）－人羊膜传代细胞（WISH）系统检测抗病毒活性。用比色MTT实验检测抗增殖活性。结果 通过突变，31和32位氨基酸获得重组突变体3132IFNα1c/86D，经限制性内切酶图分析、DNA序列和抗病毒活性测定，初步表明3132IFNα1c/86D是母体干扰素IFNα1c/86D抗病毒活性的8倍，抗增殖作用与母体干扰素相比差异无显著性。结论 改造干扰素受体结合域，可提高干扰素的抗病毒活性。     

PD-L1重组蛋白的表达及生物学活性分析

目的 构建细胞程序死亡因子1配体1(PD-L1)的重组表达质粒,在原核系统中表达并分析其生物学活性.方法 经密码子优化后合成PD-L1全基因序列,构建硫氧还原蛋白-pET43b/(PD-L1)重组表达质粒并在大肠埃希菌中表达;用ELISA验证表达产物与其受体结合的生物学活性.结果 正确构建了PD-L1重组表达质粒及其大肠埃菌基因工程菌,能稳定、高效地表达目的 蛋白,相对分子质量为47×103,目的 蛋白能与其受体特异性结合.结论 成功获得有生物学活性的PD-L1重组蛋白,为研制单克隆抗体及其与病毒感染慢性化的关系提供基础条件.     

益生菌抑制大肠埃希菌K1株黏附与侵袭的实验研究

目的评价三联活菌片中的益生菌对大肠埃希菌K1株在肠上皮黏附和侵袭的抑制作用。方法将大肠埃希菌K1株与Lovo细胞共孵育,采用黏附性抑制和竞争性排除方法,检测大肠埃希菌K1株黏附侵袭于Lovo细胞的数量,并采用流式细胞术分析益生菌对大肠埃希菌K1株诱导的细胞凋亡的抑制作用。将Sprague Dawley乳鼠随机分为实验组（益生菌和致病菌）与对照组（致病菌）。应用活菌计数法,对各组乳鼠肠道和血液中大肠埃希菌K1株进行定量检测,观察益生菌对大肠埃希菌K1株血行转移的拮抗作用。结果益生菌在体外能显著抑制大肠埃希菌K1株黏附侵袭于Lovo细胞（P〈0.01）,其抑制作用呈剂量依赖性;益生菌能显著降低大肠埃希菌K1株诱导的细胞凋亡（P〈0.01）;益生菌能显著抑制大肠埃希菌K1株的生长与血行转移,患菌血症的乳鼠数量显著降低（P〈0.01）。结论三联活菌片中益生菌能显著抑制大肠埃希菌K1株对肠上皮的黏附损伤和血行转移。     

TAT-EGFP融合蛋白的表达纯化及穿膜活性的研究

目的在大肠埃希菌中高效表达TAT-EGFP融合蛋白并鉴定纯化,然后进行穿膜活性的研究。方法以本室前期构建的重组质粒pQE-EGFP为模板,采用PCR方法特异性扩增TAT-EGFP基因序列,随后克隆于原核表达载体pQE-31,所构建的重组质粒经测序鉴定后转化大肠埃希菌JM109,IPTG诱导表达;SDS-PAGE和Western blotting鉴定表达蛋白质,经Ni2+-金属螯合亲和层析纯化,将纯化蛋白加入体外培养的小鼠黑色素瘤B16细胞中,荧光显微镜下观察TAT蛋白的穿膜活性。结果成功构建了pQE-TAT-EGFP重组质粒的,转化大肠埃希菌JM109,经IPTG诱导,目的蛋白表达率为25%,SDS-PAGE、Western blotting初步测定目的蛋白的相对分子质量(Mr)约为30160,纯化得到了目的融合蛋白TAT-EGFP。并在体外培养的B16细胞中证实TAT-EGFP融合蛋白穿透生物膜的能力。结论通过对TAT-EGFP融合蛋白穿膜活性的分析,证实了TAT具有穿膜活性,为TAT-PEⅢ融合蛋白抑瘤活性的研究提供了理论依据,也为生物大分子药物进入组织细胞内发挥治疗作用奠定了基础。     

Chemical Composition of 8 Eucalyptus species' Essential Oils and the Evaluation of Their Antibacterial, Antifungal and Antiviral activities

ABSTRACT: BACKGROUND: In 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi. METHODS: The essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out. RESULTS: Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils. CONCLUSIONS: E. odorata showed the strongest activity against S. aureus, H. influenzae, S. agalactiae, S. pyogenes, S.pneumoniae and against all the tested fungal strains. In addition, E. odorata oil showed the most cytotoxic effect. However, the best antiviral activity appeared with E. bicostata. Virus pretreatment with E. bicostata essential oil showed better antiviral activity (IC50 = 0.7 mg/ml, SI = 22.8) than cell-pretreatment (IC50 = 4.8 mg/ml, SI = 3.33). The essential oil of E. astringens showed antiviral activity only when incubated with virus prior to cell infection. This activity was dose-dependent and the antiviral activity diminished with the decreasing essential oil concentration.     

Protection of mice against encephalomyocarditis virus infection by chemically modified transfer RNAs.

Periodate or nitrous acid treatment greatly decreases the ability of unfractionated Escherichia coli transfer RNA (tRNA) to be aminoacylated by tRNA-synthetases but these treatments do not affect their antiviral activity against encephalomyocarditis virus infection of mice. Bisulphite treatment of E. coli tRNA reduces its ability to be aminoacylated by 20% and has no effect on antiviral activity. Bromine water treatment of tRNA under conditions causing extensive base modifications eliminates aminoacylation and the antiviral activity of E. coli tRNA. Periodate treatment of yeast tRNA does not affect its antiviral activity and nitrous acid treatment increases its antiviral activity to that of E. coli tRNA. The ability to be aminoacylated does not therefore appear to be essential for antiviral activity of tRNA but extensive modification (bromine water treatment) does destroy antiviral activity.     

可溶型人干细胞因子cDNA的克隆表达、复性与纯化

目的 :构建可溶型人干细胞因子 (hSCF)基因的表达载体。优化培养条件 ,实现hSCF基因在大肠杆菌中的高表达。方法 :利用PCR技术 ,以人淋巴结cDNA为模板扩增并克隆hSCF基因。用简并PCR对hSCF基因 5′端的序列进行修饰 ,以实现在大肠杆菌中的高效表达 ;用MTT比色法测定初步复性和纯化的hSCF蛋白的生物学活性。结果 :扩增并克隆了hSCF成熟肽cDNA。将其插入表达载体pBV2 2 0构建了hSCF基因的表达质粒 ,并在大肠菌中初步表达。表达量占总菌体的 2 0 %以上 ,优化培养条件后表达量可达到 4 0 %以上 ,表达产物为包涵体。将包涵体溶解在 8mol/L脲或 7mol/L盐酸胍中 ,用疏水色谱法进行复性并同时纯化 ,得到具有天然生物学活性的rhSCF蛋白。结论 :成功地克隆hSCF基因 ,并实现在原核系统中的高表达 ,所获表达菌株可用于生产以获得具有生物学活性的rhSCF蛋白产品。     

人内皮抑素基因改造、表达、纯化及活性检测

目的克隆诱变的人内皮抑素(human endostatin,hES)氨基端基因,并检测其活性。方法双酶切已诱变的人内皮抑素基因,电泳回收氨基端片段,与质粒pTYB-2重组,转化E．coli BL-21(DE3)。通过鸡胚绒毛尿囊膜(CAM)实验,MTT实验,HE染色及流式细胞术检测重组小分子人内皮抑素对新生血管生成、细胞增殖和细胞凋亡的影响。结果基因重组小分子内皮抑素对鸡胚尿囊膜新生血管生成具有明显的抑制作用;对脐静脉内皮细胞和肝癌细胞增殖的抑制存在量效关系;作用24h后,观察到细胞凋亡现象;与对照组相比,细胞凋亡数增加。结论成功构建了人内皮抑素氨基端基因工程菌,得到了具有生物活性的氨基端小分子内皮抑素,为便利临床应用奠定了基础。     

Antiviral activity of shiga toxin requires enzymatic activity and is associated with increased permeability of the target cells

This study expanded our earlier finding that Shiga toxin type 1 (Stx1) has activity against bovine leukemia virus (BLV) (W. A. Ferens and C. J. Hovde, Infect. Immun. 68:4462-4469, 2000). The Stx molecular motifs required for antiviral activity were identified, and a mechanism of Stx action on virally infected cells is suggested. Using inhibition of BLV-dependent spontaneous lymphocyte proliferation as a measure of antiviral activity, we showed that Stx2 had antiviral activity similar to that of Stx1. Enzymatic and antiviral activities of three StxA1 chain mutants deficient in enzymatic activity or aspects of receptor-mediated cytotoxicity were compared. Using protein synthesis inhibition to measure enzymatic activity, the mutant E167D was 300-fold less catalytically active than wild-type StxA1, was minimally active in antiviral assays, and did not inhibit synthesis of viral proteins. Two StxA1 mutants, A231D-G234E and StxA(1)1 (enzymatically active but unable to kill cells via the classical receptor-mediated route), had undiminished antiviral activity. Although binding of radiolabeled StxA1 to bovine blood cells or to free virus was not detected, flow cytometric analysis showed that the number of BLV-expressing cells were specifically reduced in cultures treated with Stx. These unique and rare lymphocytes were highly permeable to 40- and 70-kDa fluorescent dextrans, indicating that direct absorption of toxins by virus-expressing cells is a potential mechanism of target cell intoxication. These results support the hypothesis that Stx-producing Escherichia coli colonization of the gastrointestinal tract may benefit ruminant hosts by the ability of Stxs to exert antiviral activity.     

大鼠HSPB7蛋白的表达、活性研究及抗体制备

目的克隆SD大鼠热休克蛋白HSPB7基因,通过原核表达、纯化获得HSPB7蛋白,对其活性进行初步研究,并制备其多克隆抗体,为进一步研究HSPB7蛋白奠定基础。方法从SD大鼠心脏组织中提取总RNA,经逆转录PCR得到HSPB7基因,亚克隆入pET-43.1a(+)载体中,转化大肠杆菌BL21(DE3)菌株,获得可溶性表达产物。经纯化、质谱鉴定后进行生物学活性研究,并用纯化蛋白免疫新西兰兔,分离血清,Westernblot法测定抗体效价和特异性。结果原核表达载体pET-43.1a-HSPB7成功构建,可在大肠杆菌BL21(DE3)中诱导表达,得到相对分子质量(Mr)约18600的HSPB7蛋白,纯化蛋白经质谱鉴定正确。HSPB7具有分子伴侣活性,这种活性具有温度依赖性。用纯化的蛋白免疫新西兰大耳白兔,制备的多克隆抗体效价达1∶16000,且具有较强免疫特异性。结论得到具有生物学活性的大鼠HSPB7蛋白,成功制备了兔抗大鼠HSPB7蛋白的多克隆抗体,为后续研究提供了重要的实验材料。     

重组铜绿假单胞菌外毒素PE38KDEL的克隆、表达与活性检测

目的对铜绿假单胞菌外毒素A的编码序列进行改造,以获得相对分子质量小、活性强的重组毒素PE38KDEL。方法基于铜绿假单胞菌外毒素A的编码序列的高GC含量,通过PCR反应和酶切技术,构建重组毒素PE38KDEL基因,并于大肠杆菌表达,用Westernblot分析表达产物。为检测其生物活性,将其与靶向分子IL4突变体cpIL4(13D)融合,构建融合蛋白表达载体,并于大肠杆菌表达,表达产物经亲和色谱和阴离子交换色谱纯化后,用MTT法检测其对表达IL4受体的黑色素瘤细胞LiBr的细胞毒性。结果成功构建了PE38KDEL基因,并在大肠杆菌BL21(DE3)中得到了高效表达,表达量占细胞全蛋白的21%左右;构建了融合蛋白cpIL4(13D)PE38KDEL,并于大肠杆菌AD494(DE3)中得到高效表达,纯化后融合蛋白的纯度达95%以上,细胞毒实验证明其对黑色素瘤细胞LiBr具有良好的杀伤作用,这说明改造后的PE38KDEL是具有细胞毒效应的。结论重组毒素PE38KDEL的构建,为各种导向药物的构建奠定了基础。     

Murine monoclonal antibodies against human fibroblast (beta) interferon. Correlation of the neutralization of antiviral and antiproliferative activities

Eight mouse hybridoma lines secreting monoclonal antibodies (MoAb) to human fibroblast interferon (HuIFN-beta) were established. All MoAbs were capable of neutralizing two different biological activities of HuIFN-beta: the antiviral activity and the antiproliferative activity. Positive correlation was demonstrated between the ability of hybridoma culture supernatants to neutralize the antiviral and antiproliferative effects of human fibroblast IFN. The neutralizing capacity of individual hybridoma culture supernatants depended on the concentration of MoAb in the sample. Only one of IFN-neutralizing MoAbs has shown binding capacity to human fibroblast IFN when used in enzyme immunoassay as solid-phase antigen. This MoAb was purified to homogeneity and its specific neutralizing activity against HuIFN-beta was calculated (3.5 X 10(4) I.U. per mg).     

Gene cloning, sequencing, expression and biological activity of giant panda (Ailuropoda melanoleuca) interferon-alpha

The giant panda (Ailuropoda melanoleuca) is an endangered species and indigenous to China. In mammals, multiple subtypes of interferon-alpha (IFN-alpha) exist, most of which possess antiviral activity. Little is known about giant panda IFN-alpha genes and the role they may play in giant panda immunological responses to viruses. We have cloned genes encoding 12 giant panda IFN-alpha (AmIFN-alpha or AmIFNA) subtypes that share from 90 to 99% amino acid sequence identity. AmIFN-alpha12 has one additional amino acid at position 57, which is not present in other subtypes. Sequence identity of the AmIFN-alpha proteins encoded by the 12 genes compared to human IFN-alpha2 is approximately 58%. Unlike most of the human subtypes, each of the 12 giant panda IFN sequences has an N-glycosylation recognition site. Expression of all 12 AmIFN-alpha subtypes in 293 cells was confirmed by SDS-PAGE and Western blotting analysis. The antiviral activity and antiproliferative activity of each AmIFN-alpha subtype produced in transiently transfected 293 cell cultures were tested in vitro. All AmIFN-alpha subtypes were found to be stable at pH 2 or 65 degrees C and to exhibit antiviral activity. Some IFN subtypes (AmIFN-alpha8 and AmIFN-alpha4) showed higher biological activity levels than others, whereas AmIFN-alpha11 exhibited lower activity. AmIFN-alpha had various antiproliferative activities to different target cells. To B16 cells, AmIFN-alpha3, AmIFN-alpha4, AmIFN-alpha8 had the highest activities, while to K562 cells, AmIFN-alpha3, AmIFN-alpha7, AmIFN-alpha10 had the highest activities. The various IFN-alpha subtypes displayed a good correlation between their antiviral and antiproliferative potencies.