密码子优化的肺炎支原体P1蛋白在大肠杆菌中的克隆表达

目的:获得密码子优化的肺炎支原体P1黏附蛋白优势表位抗原基因,并在大肠杆菌中表达,为临床诊断试剂和疫苗研制打下基础。方法:采用生物信息学分析肺炎支原体P1蛋白的抗原表位,筛选特异性P1蛋白优势表位区;采用大肠杆菌优势密码子,设计上述P1蛋白优势表位基因序列;采用退火PCR技术合成上述基因,并利用载体pGEX-4T-2实现P1优势表位抗原在大肠杆菌中的表达;采用ELISA法对纯化的P1抗原活性进行测定。结果:肺炎支原体P1蛋白特异性抗原表位主要位于1154~1521 aa,获得的P1优化密码子基因平行突变37个稀有密码子和2个终止密码子;在大肠杆菌中表达的GST-P1融合蛋白的相对分子质量为65.9×103,纯化后重组抗原能与肺炎支原体感染者血清发生特异性的免疫反应。结论:采用密码子优化基因合成技术实现了肺炎支原体P1优势表位抗原在大肠杆菌中的高效表达,为肺炎支原体感染的诊断试剂研究提供了重要参考。     

人3型腺病毒六邻体高变区HVR1、HVR2、HVR5、HVR7的氨基酸修饰限制研究

传统腺病毒载体的局限性使得外源抗原以衣壳融合的方式在腺病毒载体上的应用越来越广泛,但是在3型腺病毒（Adenovirus serotype 3, Ad3)载体六邻体高变区(Hypervariable region,HVR)改造过程中经常出现无法成功拯救病毒的情况,本研究主要根据对生物信息学预测的HVR1,HVR2,HVR5,HVR7中某些氨基酸进行删减或保留,通过构建重组Ad3载体pBRAdΔE3GFP-mHexon,转染AD293细胞,验证Ad3载体在六邻体高变区的这些氨基酸有所改动时对病毒拯救的影响。由此获得高变区HVR1、HVR2、HVR5和HVR7在基因工程改造中应该保留的氨基酸的数据,这一研究结果为人3型腺病毒六邻体融合表达策略提供了操作依据,也为人3型腺病毒六邻体表达外源抗原表位,作为多价疫苗载体展示平台的应用奠定了基础。     

2012年大连市流行性角结膜炎疫情的病原鉴定与基因特征分析

目的 鉴定一起大连市流行性角结膜炎疫情的病原体及型别.方法 采用荧光PCR方法针对30份眼拭标本进行检测,确定病原,并针对特定片段扩增产物测序进行分子定型.结果 21份标本荧光PCR检测结果为腺病毒阳性,核苷酸序列与人腺病毒15、29、56及其重组型高度同源,多重序列比对后构建的系统进化树上与人腺病毒56及其重组型位于同一分支.结论 本次疫情的致病病原为D亚属人腺病毒,疑为人腺病毒56型或其重组型.后续需要开展对五邻体(Penton)及纤突(Fi-ber)基因的全核苷酸序列测定及生物信息学分析最终确定型别.     

快速获取55型腺病毒基因组序列的方法

【目的】建立快速获取55型腺病毒的全长基因组序列的方法。【方法】根据55型腺病毒的基因组特点,设计覆盖55型腺病毒基因组序列的12对引物,分别以55型腺病毒DNA为模板,扩增得到12个PCR产物,通过对12个PCR产物测序及序列拼接,获得55型腺病毒的全长基因组序列。【结果】从本院急性上呼吸道感染者咽拭子标本中分离得到一株55型腺病毒毒株SF04/SC/2016,以其DNA为模板扩增成功获得12个PCR产物,对其进行测序,并对12段序列进行拼接得到55型腺病毒的全长基因组序列,与已报到的各型腺病毒序列进行比对,采用邻位相连法构建系统发育进化树,所得序列与55型腺病毒处于同一分支,进一步确认该病原体为55型腺病毒。【结论】研究公布的序列和方法,能够实现更方便对腺病毒的快速测序,为揭示55型腺病毒的进化特点及制订疾病防控策略提供了有效手段。     

甲型H1N1流感病毒NA、PB2和PA表位抗原区段的克隆和表达

目的:分析比对甲型H1N1流感病毒神经氨酸酶(NA)、聚合酶B2(PB2)和聚合酶A(PA)抗原的序列,克隆表达保守的和变异的表位抗原区段,为免疫学诊断试剂的研究提供候选抗原。方法:采用BioSun生物学软件比较新近公布的A/H1N1流感病毒和我国猪流感病毒浙江株NA、PB2和PA抗原序列,并预测筛选NA、PB2和PA抗原表位保守区段与变异区段,采用PCR逐步合成法合成NA、PB2和PA表位抗原区段基因序列,并利用原核表达载体pBVIL1进行克隆表达。结果:筛选的保守表位抗原区段和变异表位抗原区段为NA/135～180aa、NA/310～350aa、PB2/1～80aa、PA/41～90aa、PA/231～280aa和PA/341～400aa;获得6条表位抗原区段基因序列,且6条表位抗原区段均获得了高效表达,得到纯化后的抗原。结论:获得了A/H1N1流感病毒NA、PB2和PA表位抗原区段,为进一步研制特异的甲型流感病毒快速诊断试剂提供了抗原储备。     

仙台病毒BB1株6个编码基因的克隆及表达

在仙台病毒BB1株全基因组序列测定的基础上,用反转录和PCR方法获得了核蛋白基因(N),磷蛋白基因(P),神经血凝素基因(HN),基质蛋白基因(M)、融合蛋白基因(F)和聚合酶蛋白基因(L)等6个编码基因全长克隆;测序结果表明,其序列与Genbank中登录的序列(DQ219803)完全一致。为了提供仙台病毒基因组载体拯救和包装所需的反式作用蛋白,将N、P、M、F、HN和L分别克隆到腺病毒穿梭表达载体pDC316上,将它们分别与腺病毒基因组质粒pBHGlox△E1,3Cre共转染HEK293细胞,获得了6种复制缺陷性重组腺病毒Ad5-N、Ad5-P、Ad5-M、Ad5-F、Ad5-HN和Ad5-L。酶切结果表明6种重组腺病毒穿梭质粒构建正确;用PCR方法证明所获得的6种重组腺病毒分别携带了上述6个编码基因;用重组腺病毒感染LLC-MK2细胞后用Western blotting和免疫荧光方法检测到了相应仙台病毒编码基因的表达。本研究为仙台病毒BB1株全长基因组的拼接和病毒载体包装系统组建打下了基础。     

人呼吸道合胞病毒M蛋白非复制型重组腺病毒的构建和鉴定

人呼吸道合胞病毒（human respiratory syncytial virus, RSV)基质蛋白（matrix protein,M）在RSV形态发生上具有重要作用,因含有CTL抗原表位,在疫苗研究上具有一定意义。为此,应用RT-PCR 方法从感染RSV的HEp-2 细胞中扩增获得M蛋白基因,构建了含M基因的非复制型重组腺病毒并进行表达和鉴定。基因序列分析显示RSV M基因仅有一处碱基发生错义突变。非复制型重组腺病毒DNA分子FGAd/RSVM转染293细胞,观察到细胞出现CPE,RT-PCR发现M基因有转录,Western blotting及间接免疫荧光分析检测到M蛋白。成功克隆A亚型RSV Long株M基因,并获得一株可表达A亚型RSV M蛋白的非复制型重组腺病毒FGAd/RSVM,可用于体内研究观察其免疫效果及免疫保护作用。     

猪圆环病毒Ⅱ型Cap蛋白重组腺病毒的构建与鉴定

猪圆环病毒Ⅱ型(PCV2)是近年来新发现的引起仔猪多系统衰弱综合症的必需病原,含有两个主要的阅读框ORF1和ORF2,分别编码复制相关蛋白(Rep)和核衣壳蛋白(Cap),其中Cap含有病毒主要抗原表位,是研究PCV2基因工程苗的主要候选目的基因。本研究利用PCR技术将Cap蛋白基因克隆入人5型腺病毒穿梭载体(pShuttle-CMV),与腺病毒骨架载体(pAdEasyTM)共转化大肠杆菌BJ5183进行同源重组并转染HEK-293A细胞,经多次亚克隆获得了重组腺病毒rAd-Cap,测定其TCID50为1013.7/mL。用RT-PCR、间接ELISA、Westernblot和IPMA等方法证明了Cap蛋白在腺病毒中获得表达。该研究为发展PCV2的重组腺病毒基因工程疫苗奠定了基础。     

分泌睫状神经营养因子腺病毒载体的构建及小量复制病毒增强其分泌表 达的研究

目的:探讨复制型腺病毒能否增强增殖缺陷型腺病毒Ad5-hCNTF所携带外源基因的表达分泌。方法:亚克隆获得分泌型睫状神经营养因子的基因(ciliary neurotrophic factor),然后将此基因插入到穿梭质粒pshuttle。pshuttle-hCNTF经pme1酶切后,CIAP去磷酸化,利用Ad-EASY腺病毒制备系统,将其与腺病毒骨架质粒pAdEasy-1共同转化大肠杆菌BJ5183,通过同源重组,筛选出含目的基因的重组型腺病毒质粒的菌株,获得大量该质粒后转染病毒包装细胞AD-293,成功包装出一种血清5型增殖缺陷型腺病毒Ad5-hCNTF。结果:经PCR鉴定该病毒含有该基因片断,Western blotting证实该病毒感染细胞后能表达CNTF蛋白。采用ELISA法检测培养液证实感染细胞能高水平地分泌CNTF。结论:体外实验表明在不同滴度的复制型腺病毒Ad5-E1+E3+的带动下,该病毒感染细胞后分泌表达目的蛋白的水平显著提高,为今后应用Ad作为基因治疗的载体提供实验证据。     

An immunodominant domain in adenovirus type 2 early region 1A proteins.

Six independent rat hybridoma cell lines producing monoclonal antibodies to human subgroup C adenovirus early region 1A (E1A) proteins were isolated. Competition binding experiments revealed that each of the monoclonal antibodies was directed against the same epitope or overlapping cluster of epitopes on the E1A proteins. Viral E1A deletion mutants and deleted forms of E1A proteins expressed in Escherichia coli were used to localize the antibody recognition sites to sequences between amino acids 23 and 120, encoded within the first exon of the E1A gene. Similarly, polyclonal antisera raised against the trpE-E1A fusion protein, as well as against the native, biologically active E1A protein, were also directed primarily against this immunodominant region.     

人乳头瘤病毒11型L2NE7E6融合蛋白的原核表达及其诱发的T细胞免疫反应

目的:在原核表达系统中表达人乳头瘤病毒11型(HPV11)L2NE7E6融合蛋白,纯化蛋白后免疫小鼠,检测其诱发的T细胞免疫水平,并筛选HPV11 E6、E7特异的T细胞表位肽。方法:用重叠PCR方法构建HPV11L2NE7E6融合基因并插入原核表达质粒,在大肠杆菌中经IPTG诱导表达融合蛋白L2NE7E6,用SDS-PAGE和West-ern印迹鉴定融合蛋白的表达。Q柱纯化蛋白后免疫C57BL/6小鼠,分别用覆盖HPV11 E6和E7蛋白序列的肽库,采用酶联免疫斑点法(ELISPOT)检测其诱发的E7、E6特异的T细胞免疫反应,并筛选E7、E6特异的T细胞表位肽。结果:在原核表达系统中有效表达了HPV11 L2NE7E6融合蛋白,蛋白纯化后免疫C57BL/6小鼠,分别能检测到针对HPV11 E6、E7肽库刺激产生的特异性T细胞免疫反应。经肽池筛选到1条强的E6 T细胞表位肽E6aa41-55(AEI-YAYAYKNLKVVW);而E7只筛选到2条弱的T细胞表位肽,分别为E7aa53-67(QILTCCCGCDSNVRL)和E7aa73-87(DGDIRQLQDLLLGTL)。结论:HPV11 L2NE7E6融合蛋白能诱发小鼠产生E6、E7特异性细胞免疫反应,可作为尖锐湿疣免疫治疗候选疫苗。     

T cell immunity to type II collagen in the biobreeding rat: the identification and characterization of RT1u-restricted T cell epitopes on alpha 1(II)

Susceptibility to experimental collagen-induced arthritis in rodents is dependent on MHC class II elements to bind peptides from the type II collagen (CII) molecule. Although a substantial body of data has been reported in mice defining these peptide Ags, little has been reported in rats. In this study, we investigate the locations and sequences of CII peptides, which are bound by RT1(u) molecules, expressed by diabetic-resistant, arthritis-susceptible Biobreeding rats, and, in turn, stimulate CII-specific T cells. By using overlapping and substituted peptide homologues of CII, we have identified and characterized an immunodominant and five subdominant epitopes on CII, which stimulate RT1(u)-restricted T cell proliferation. The immunodominant epitope, CII (186-192), contains a QGPRG core sequence, which was found in a subdominant epitope CII (906-916). Similar sequences containing single conservative substitutions were identified in three other epitopes. One, CII (263-272), contained a conservatively substituted R-->K substitution, whereas CII (880-889) and CII (906-916) contained nonconservative substitutions, i.e., P-->D and R-->M, respectively. Homologue peptides containing these sequences stimulated T cell proliferative responses, although less intensely than peptides containing CII (186-192). Substituting QGR residues in the QGPRG core with alanine, isoleucine, or proline reduced proliferation, as did substituting flanking E and G residues at the N terminus and E at the C terminus. Collectively, these data indicate that RT1(u)-restricted immunodominant and several subdominant epitopes on CII often share a QGPRG-like motif, with conservative substitutions present at either P or R positions. This motif is similar to one recognized by collagen-induced arthritis-susceptible HLA-DR1- and HLA-DR4-transgenic mice.     

B Cell Epitopes within VP1 of Type O Foot-and-mouth Disease Virus for Detection of Viral Antibodies

In this study,the coding region of type O FMDV capsid protein VP1 and a series of codon optimized DNA sequences coding for VP1 amino acid residues 141-160(epitope1),tandem repeat 200-213(epitope2(+2)) and the combination of two epitopes(epitope1-2)was genetically cloned into the prokaryotic expression vector pPROExHTb and pGEX4T-1,respectively.VP1 and the fused epitopes GST-E1,GST-E2(+2)and GST-E1-2 were successfully solubly expressed in the cytoplasm of Escherichia coli and Western blot analysis demonstrat...     

A组轮状病毒多个结构蛋白抗原表位的串联表达及其免疫原性的检测

从北京腹泻婴儿粪便提取的轮状病毒(rotavirus,RV)(T114株)的RNA中,克隆到轮状病毒结构蛋白基因vp4,vp6和vp7的全长cDNA,对它们编码的蛋白质序列和可能的抗原表位肽进行了预测,选择了RV主要抗原蛋白VP7、VP6和VP4的4个抗原表位肽,通过人工合成DNA的方式将这些抗原表位肽基因串联融合成一个阅读框RME(rotavirus multipleepitopes,RME)并构建原核表达载体.大肠杆菌表达的RME在ELISA反应中可被RV多克隆抗体识别,纯化的RME蛋白注射免疫小鼠可诱导特异性免疫应答,产生高滴度的同源氨基酸序列特异抗体和人RV抗体,其中针对RME的IgG抗体滴度达到l∶40 000,针对单个抗原表位EV7、EV6和EV4的IgG抗体滴度达l∶10 000～l∶20 000,针对RV Wa株的IgG抗体滴度较低为l∶2 500,但能特异地中和该病毒对MAC145细胞的侵染.上述结果为新型RV基因工程疫苗的研发提供了论据和基础.     

Epitope analysis of the FanC subunit protein of the K99 (F5) fimbriae of enterotoxigenic Escherichia coli using a recombinant fusion technique

We have used a recombinant approach to characterise the B- and T-cell epitopes of FanC, the major subunit polypeptide of K99 (F5) fimbriae of enterotoxigenic Escherichia coli strains. This involved the fusion of FanC and its carboxy-terminal truncated derivatives to a reporter, the E. coli alkaline phosphatase (PhoA), generating stable, recombinant fusions. The B-cell epitopes of FanC were characterised by Western blotting of FanC::PhoA fusion proteins with a polyclonal mouse antiserum directed against K99 fimbrial antigen, and with a panel of monoclonal antibodies generated to the K99 antigen. An attempt to characterise the T-cell epitopes of the fimbrial subunit was made by standard in vitro T-cell proliferation assay. Our results suggest that the B-cell epitopes of FanC are likely to be continuous, with a potentially immunodominant epitope at the carboxy-terminus. However, T-cell proliferation assays with the FanC::PhoA fusion proteins did not indicate any immunodominant T-cell epitope(s). We hypothesise that fusion of FanC peptides to PhoA had resulted in altered folding of the peptides for antibody and T-cell recognition, highlighting the potential problems and drawbacks of the recombinant fusion technique in defining the epitopes of certain proteins.     

Increasing the expression levels of papillomavirus major capsid protein in Escherichia coli by N-terminal deletion

The major capsid protein L1 of human papillomavirus (HPV) contains the immunodominant neutralization epitopes of the virus and can auto-assembles to form virus-like particles (VLPs). Therefore, HPV L1 capsid proteins have been well investigated as potential vaccine candidates. To express large quantities of human papillomavirus type 16 (HPV-16) L1 in Escherichia coli (E. coli), The HPV-16 L1 gene was cloned into pGEX-4T-1, resulting in only low expression levels of HPV-16 L1 in E. coli. The first 129 nucleotides of the 5' end of the L1 gene, which contains the major inhibitory RNA element, were then deleted. The deletion RNA was efficiently translated, resulting in about 2-fold higher L1 accumulation in E. coli. The N-terminal amino-acid deletion did not affect the ability of L1 to auto-assemble in E. coli and form small VLPs.     

乙肝前S2抗原决定簇串联体与核心抗原的基因融合与表达

乙肝前Ｓ２（ＨＢＶＰｒｅＳ２）肽段由５５个氨基酸组成,其Ｎ端肽段含Ｔｈ和Ｂ细胞抗原决定簇,为增强ＰｒｅＳ２的抗原性,本实验采用将化学合成的ＰｒｅＳ２ｅｐｉｔｏｐｅ（１２０－１４５）基因以串联方式与ＨＢｃＡｇ的基因进行了融合,融合基因在大肠杆菌中获得表达,并通过ＥＬＩＳＡ比较研究了融合蛋白中ＰｒｅＳ_２ｅｐｉｔｏｐｅ单体及串联体的抗原性差异。     

Analysis of adenovirus transforming proteins from early regions 1A and 1B with antisera to inducible fusion antigens produced in Escherichia coli.

Plasmid vectors were constructed which expressed three adenovirus tumor antigens fused to a portion of the trpE protein of Escherichia coli. Insertion of adenovirus type 2 DNA from early region 1A (E1A) into such a plasmid led to a fusion protein which contained the C-terminal 266 amino acids of the 289-amino acid protein encoded by the viral 13S mRNA. Similarly, insertion of adenovirus type 5 DNA corresponding to the E1B 55- and 21-kilodalton proteins led to production of fusion proteins containing amino acid sequences from these proteins. After induction with indoleacrylic acid, fusion proteins accumulated stably in the E. coli cells. By using a simple extraction of insoluble protein, 1 to 10 mg of fusion protein per liter of culture was obtained. The fusion proteins were purified on preparative polyacrylamide gels and used to immunize rabbits. Specific antisera for the E1A 289- and closely related 243-amino acid proteins and the E1B 55- and 21-kilodalton proteins were obtained. These sera were used to immunoprecipitate the tumor antigens in cells infected with wild-type and various mutants of adenovirus or to analyze them by an immunoblotting procedure. Mutant E1A proteins in which the C-terminal 70 amino acids are deleted were phosphorylated to much lower extents than the wild-type E1A proteins. This indicates that the deleted region is important for the process of phosphorylation. The E1A proteins were extracted, sedimented in glycerol gradients, analyzed by immunoprecipitation, and found to sediment primarily as monomers.