口蹄疫病毒基因组RNA结构与功能研究进展

1 概述 口蹄疫病毒(foot-and-mouth disease virus,FMDV)属小RNA病毒科FMDV属,根据动物交叉保护和血清学试验分为O、A、C、SAT1、SAT2、SAT3和Asial 7个血清型,型间无交叉反应.每型又根据抗原亲缘关系分为不同亚型.小RNA病毒科包括鼻病毒、肠道病毒、甲肝病毒、心病毒和口蹄疫病毒5个属.     

口蹄疫病毒Asia1/YNBS/58株全基因组序列分析

口蹄疫是由口蹄疫病毒(Foot-and-mouth dis-ease virus,FMDV)感染引起的偶蹄动物(猪、牛、羊、骆驼等)共患的一种急性、烈性、接触性传染病。FMDV是小核糖核酸病毒科(Picornaviridae)口蹄疫病毒属(Aphthovirus)的成员,有7个血清型,分别为O、A、C、Asia1、SAT1、SAT2、SAT3,完整     

Asia Ⅰ型口蹄疫病毒中和表位与羊IgG重链恒定区的融合表达及免疫原性测定

VP1蛋白是口蹄疫病毒(Foot-and-Mouth Disease Virus,FMDV)诱导机体产生抗病毒感染免疫的主要蛋白,含有病毒的若干中和表位.本研究设计和合成了由Asia Ⅰ型FMDV VP1蛋白136～160aa和198～211aa两个表位组成的重复串联表位的编码基因,并克隆了羊IgG重链恒定区编码基因.利用BamH I、EcoR I和Xho I位点将2个基因片段依次克隆到pPROExHTb载体,构建成重组质粒pPRO-FshIgG,将其转化大肠杆菌BL21(DE3)感受态细胞,以IPTG诱导表达得到融合蛋白FshIgG.100μg FshIgG蛋白免疫豚鼠后刺激豚鼠产生了高效价的FMDV中和抗体,而且使这些免疫豚鼠在用200 ID_(50)剂量FMDV攻击时得到了完全保护.由此证明,羊IgG重链恒定区蛋白能够作为FMDV表位肽的载体,而融合蛋白FshIgG可成为一种口蹄疫表位疫苗候选物用于口蹄疫的预防.     

O型口蹄疫病毒VP1 T细胞、B细胞表位双拷贝基因与大肠杆菌LTB、STⅠ肠毒素基因融合表达产物的免疫应答

合成O型口蹄疫病毒VP1蛋白中与细胞免疫(21～40表位肽)及体液免疫(141～160表位肽)相关的基因序列2020VP1,运用基因工程技术构建了含有肠毒素大肠杆菌LTB、STⅠ基因及双拷贝2020VP1的融合表达载体r2020-B-2020-STⅠ,转化宿主菌 BL21(DE3) RIL后的表达产物经SDS-PAGE分析,结果显示重组融合蛋白的分子量约为45 kDa,表达量较高.ELISA实验结果显示,融合蛋白能与霍乱毒素(cholera toxin)CTB抗体特异结合.动物实验表明,融合蛋白能够诱发兔体产生较强的FMDV中和抗体,免疫豚鼠在低浓度FMDV刺激下能够产生特异性T淋巴细胞增殖反应,说明融合蛋白能诱导机体产生FMDV特异性细胞及体液免疫反应;同时,融合蛋白免疫雌鼠能够抵抗大肠杆菌强毒株攻击,免疫兔体能够产生STⅠ中和抗体,且融合蛋白不具STⅠ毒性,证明融合蛋白具有良好的LTB、STⅠ免疫原性.实验结果表明,此融合蛋白具有开发成为口蹄疫及肠毒素腹泻联合疫苗的应用价值.     

链特异性RT-PCR方法检测口蹄疫病毒负链RNA

旨在建立一种快速、灵敏、特异的检测口蹄疫病毒在复制过程中产生的负链RNA的方法。根据口蹄疫病毒(foot-and-mouth disease virus,FMDV)病毒5’-非编码区(5’-UTR)基因序列,设计了5条引物链特异性RT-PCR引物,建立检测口蹄疫病毒负链RNA的链特异性RT-PCR方法。提取FMD病毒RNA,应用设计的正向引物T1-H1做反转录引物,经反转录和RNA酶A消化后,再经两轮链特异性PCR扩增,可特异性地检测FMDV在复制过程中产生的负链RNA。所建立的检测口蹄疫病毒负链RNA的链特异性RT-PCR方法是一种可靠的方法,在确定细胞培养物和动物感染FMDV的病毒复制和了解病毒的致病性研究中具有应用前景。     

A型口蹄疫病毒VP0基因的克隆及原核表达

从实验室冻存的含A型口蹄疫病毒的细胞中提取FMDV总RNA,通过RT-PCR获得cDNA.并根据FMDV全基因组序列设计了一对针对VP0基因的引物,通过PCR扩增得到目的基因VP0并亚克隆入pMD18-T载体.将鉴定出的阳性质粒和表达载体pET32a用BamH Ⅰ和HindⅢ双酶切回收后连接获得阳性重组质粒pET32-VP0.用IPTG诱导重组质粒表达目的蛋白VP0并用SDS-PAGE进行检测.表达产物用镍亲和树脂进行了纯化.结果证明,口蹄疫病毒VP0蛋白在大肠杆菌中获得了高效表达且表达产物得到了纯化,为实验室进一步的研究提供了重要的材料.     

三株口蹄疫病毒的克隆和基因型鉴定

目的：将O、A、Asia—Ⅰ型等3株口蹄疫病毒（FMDV）VP3-VP1—2A区域的一个片段克隆到pMD18-T载体上,构建阳性重组质粒,并且鉴定3株病毒所属的基因型。方法：将从中国农业科学院兰州兽医研究所获得的O、A、Asia—Ⅰ型灭活FMDV提取RNA作为模板,采用RT-PCR技术扩增了VP3-VP1-2A区域的一个约1070bp的片段,包含了全部的VP1序列;将其克隆到pMD18-T载体上,鉴定后得到阳性重组质粒;将目的片段进行序列测定、分析、绘制系统发育树,进而确定各灭活病毒的基因型。结果与结论：经鉴定,O型灭活FMDV属Cathay基因型,它与该基因型3条参考毒株序列的相似性在87％以上;A型灭活FMDV与参考株的相似性差异较大,但在系统发育树上可以看出该毒株属于Asia基因型;Asia-Ⅰ型FMDV只有1个基因型,将测序结果在NCBI网站上BIJAST,证实该灭活病毒为Asia—Ⅰ型。     

口蹄疫病毒主要的抗原cDNA在大肠杆菌中的无性繁殖及其表达

口蹄疫病毒(FMDV)单键基因组RNA的双键DNA拷贝在大肠杆菌质粒pBR322中无性繁殖。确立了病毒基因组的限制性图谱,并与病毒的生化图谱作了相应的排列。病毒的主要抗原,结构蛋白VP1的编码序列作了鉴定,并把该序列插入质粒载体,于λ噬菌体P_L促进子的控制下这一序列得到了表达,通过放射免疫检测方法证明了抗原多肽在一种合适寄主中的合成。     

制服口蹄疫FMDV基因工程疫苗获得成功

口蹄疫是家畜最有破坏力的疾病,它是由口蹄疫病毒所引起的。1967--1968年期间由于这种病疫的流行造成重大损失,将近50万头家畜受毁。 抗口蹄疫病毒疫苗是制服这种病害的有力工具,通常获得这种疫苗是靠组织培养制取,用乙酰乙烯脒(acetylethylenimine)较易纯化,获得免疫力较强,并持续3--6个月(Marwick C.)。但这种制法常受到很大限制,也不便宜,为此,美国近几年来便用基因工程方法制取疫苗取得进展,他们将口蹄疫病毒VP3外壳蛋白(注:FMDV粒子含有四种衣壳蛋白即VP1、VP2、VP3、VP4,是在感染细胞中合成)基因插入到pBR     

制服口蹄疫FMDV基因工程疫苗获得成功

口蹄疫是家畜最有破坏力的疾病,它是由口蹄疫病毒所引起的。1967——1968年期间由于这种病疫的流行造成重大损失,将近50万头家畜受毁。 抗口蹄疫病毒疫苗是制服这种病害的有力工具,通常获得这种疫苗是靠组织培养制取,用乙酰乙烯脒(acetylethylenimine)较易纯化,获得免疫力较强,并持续3——6个月(Marwick C.)。但这种制法常受到很大限制,也不便宜,为此,美国近几年来便用基因工程方法制取疫苗取得进展,他们将口蹄疫病毒VP3外壳蛋白(注:FMDV粒子含有四种衣壳蛋白即VP1、VP2、VP3、VP4,是在感染细胞中合成)基因插入到pBR     

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...     

猪口蹄疫病毒多抗原表位重组腺病毒的构建与鉴定

本研究设计构建了含有猪O型口蹄疫病毒VP1（21—60）-（141-160）-（200—213）位氨基酸的基因的重组腺病毒质粒pAd-VP,经PacI酶切后转染HEK-293A细胞,3次噬斑纯化获得了重组腺病毒rAd—VP。该重组腺病毒于HEK-293A细胞连续传代至20代效价稳定,TCID50为10^-10／mL。RT—PCR检测证明目的基因在mRNA水平上可有效表达;应用O型口蹄疫病毒标准阳性血清进行间接荧光抗体试验,在rAdVP感染的HEK-293A细胞的胞质可见清晰荧光。证明该重组腺病毒对VP1（21-60）-（141—160）-（200—213）位氨基酸的基因进行了成功的表达,从而为FMDV多抗原表位腺病毒活载体疫苗的研究奠定了基础。     

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 pP_ROExHTb 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 demonstrated they retained antigenicity. Indirect VP1-ELISA and epitope ELISAs were subsequently developed to screen a panel of 80 field pig sera using LPB-ELISA as a standard test. For VP1-ELISA and all the epitope ELISAs, there were clear distinctions between the FMDV-positive and the FMDV-negative samples. Cross-reactions with pig sera positive to the viruses of swine vesicular disease virus that produce clinically indistinguishable syndromes in pigs or guinea pig antisera to FMDV strains of type A, C and Asia1 did not occur. The relative sensitivity and specificity for the GST-E1 ELISA, GST-E2 (+2), GST-E1-2 ELISA and VP1-ELISA in comparison with LPB-ELISA were 93.3% and 85.0%, 95.0% and 90%, 100% and 81.8%, 96.6% and 80.9% respectively. This study shows the potential use of the aforementioned epitopes as alternatives to the complex antigens used in current detection for antibody to FMDV structural proteins.     

Recombinant Bivalent Vaccine against Foot-and-Mouth Disease VirusSerotype O／A Infection in Guinea Pig

Foot-and-mouth disease (FMD) is a highly contagiousdisease of cloven-hoofed animals such as cattle and pig.The disease causes explosive epidemics and heavyeconomic losses in the agriculture worldwide [1]. FMDvirus (FMDV) shows a high genetic and antigenicvariability, and has seven serotypes: O, A, C, AsiaI, SAT1,SAT2 and SAT3 [2]. The FMDV control is mainly imple-mented using chemically inactivated virus vaccines, whichmay contain residual living virus and pose a risk of virusreleas…     

Use of substituted and tandem-repeated peptides to probe the relevance of the highly conserved RGD tripeptide in the immune response against foot-and-mouth disease virus

Antigenic site A of foot-and-mouth disease virus (FMDV) is an exposed, mobile loop which includes a central, highly conserved Arg-Gly-Asp tripeptide (RGD, VP1 residues 141–143 in serotype C) thought to be part of the cell attachment site. We have analyzed the contribution of RGD to the interaction of site A with antibodies by incorporating selected amino acid replacements at RGD into synthetic peptides representing site A, and analyzing the reactivity of substituted peptides with site A-specific monoclonal antibodies (MAbs). Replacement of Arg-141, Gly-142 or Asp-143 by alanine resulted in the loss of one, three and five epitopes, respectively, out of seven epitopes probed. Other replacements resulted in the loss of even larger numbers of epitopes, suggesting that the amino acids of the RGD region are either directly involved in interaction with antibodies or that they exert an important influence on the interaction of surrounding residues with antibodies. Thus, we explored the ability of tandem repeats of the RGDL sequence (corresponding to FMDV C-S8cl) to evoke neutralizing antibodies in rabbits and guinea pigs. Neutralizing activity was generally low but with a broad specificity for different FMDV serotypes and variants. Significant decreases in neutralizing titers were observed with boosting, suggesting a possible suppression of those anti-peptide antibodies which may also be directed to cellular RGD sequences. The results point to an involvement of RGD in the antigenic structure of site A, and open the possibility that broadly neutralizing antibodies might be induced by tandem repeats of the critical, conserved domain.     

O型口蹄疫病毒VP1 T细胞、B细胞表位双拷贝基因与大肠杆菌LTB、STI肠毒素基因融合表达产物的免疫应答

合成O型口蹄疫病毒VP1蛋白中与细胞免疫（21～40表位肽）及体液免疫（141～160表位肽）相关的基因序列2020VP1,运用基因工程技术构建了含有肠毒素大肠杆菌LTB、STI基因及双拷贝2020VP1的融合表达载体r2020-B-2020-STI,转化宿主菌BL21(DE3)RIL后的表达产物经SDS-PAGE分析,结果显示重组融合蛋白的分子量约为45kDa,表达量较高。ELISA实验结果显示,融合蛋白能与霍乱毒素（choleratoxin）CTB抗体特异结合。动物实验表明,融合蛋白能够诱发兔体产生较强的FMDV中和抗体,免疫豚鼠在低浓度FMDV刺激下能够产生特异性T淋巴细胞增殖反应,说明融合蛋白能诱导机体产生FMDV特异性细胞及体液免疫反应;同时,融合蛋白免疫雌鼠能够抵抗大肠杆菌强毒株攻击,免疫兔体能够产生STI中和抗体,且融合蛋白不具STI毒性,证明融合蛋白具有良好的LTB、STI免疫原性。实验结果表明,此融合蛋白具有开发成为口蹄疫及肠毒素腹泻联合疫苗的应用价值。     

Identification of T-cell epitopes in nonstructural proteins of foot-and-mouth disease virus

Porcine T-cell recognition of foot-and-mouth disease virus (FMDV) nonstructural proteins (NSP) was tested using in vitro lymphoproliferative responses. Lymphocytes were obtained from outbred pigs experimentally infected with FMDV. Of the different NSP, polypeptides 3A, 3B, and 3C gave the highest stimulations in the in vitro assays. The use of overlapping synthetic peptides allowed the identification of amino acid regions within these proteins that were efficiently recognized by the lymphocytes. The sequences of some of these antigenic peptides were highly conserved among different FMDV serotypes. They elicited major histocompatibility complex-restricted responses with lymphocytes from pigs infected with either a type C virus or reinfected with a heterologous FMDV. A tandem peptide containing the T-cell peptide 3A[21-35] and the B-cell antigenic site VP1[137-156] also efficiently stimulated lymphocytes from infected animals in vitro. Furthermore, this tandem peptide elicited significant levels of serotype-specific antiviral activity, a result consistent with the induction of anti-FMDV antibodies. Thus, inclusion in the peptide formulation of a T-cell epitope derived from the NSP 3A possessing the capacity to induce T helper activity can allow cooperative induction of anti-FMDV antibodies by B cells.     

A T cell epitope in VP1 of foot-and-mouth disease virus is immunodominant for vaccinated cattle.

Synthetic peptides representing regions of the VP1 protein of foot-and-mouth disease virus strain 01 Kaufbeuren were screened for their ability to stimulate proliferation of PBMC from virus vaccinated cattle. Sites were identified at residue 21-40 (peptide FMDV32) and in the region C-terminal to residue 161. Cells responding to FMDV32 were MHC class II-restricted, CD4+ and secreted IL-2. Thus, this region is defined as a Th site. Of 19 virus vaccinated Friesian cattle, 89% (17/19) responded to purified virus while 37% (7/19; 41% of virus responders) also responded to FMDV32 suggesting that this site is immunodominant for the cattle used. Furthermore, immunisation of FMDV32 responder and non-responder cattle with a related peptide, FMDV5 (FMDV32 co-linearly synthesized with the 141-160 VP1 B cell site), induced neutralizing antibody and a virus-specific T cell population in the FMDV32-responder but not the non-responder animals.