传染性胰腺坏死病病毒分离株VP2基因抗原表位区融合表达及免疫特性的分析

利用RT-PCR方法扩增出IPNV-ZYX分离株主要结构蛋白VP2的抗原表位区基因(616 bp), 命名为IPNV VP2 COE, 将其克隆到pCold TF表达载体中构建重组质粒pCold TF-VP2 COE, 在大肠杆菌BL21(DH5α)感受态表达, 经SDS-PAGE电泳分析, 表达蛋白约78 ku, 用镍离子亲和层析柱纯化该蛋白, 制备抗血清, 间接ELISA结果显示, IPNV (ATCC VR-1318)细胞培养物与鼠抗VP2 COE蛋白血清发生特异性反应, 效价为1∶12 800; 间接免疫荧光结果显示, 鼠抗VP2 COE血清可与黑龙江某渔场已知感染IPNV虹鳟肝组织产生特异性的荧光, 以上两项结果表明, 表达IPNV VP2 COE蛋白具有良好的免疫原性和免疫反应性, 为IPNV检测方法的建立及疫苗的制备提供理论依据     

传染性造血器官坏死病毒糖蛋白抗血清的制备及应用

应用逆转录聚合酶链式反应(RT-PCR)从传染性造血器官坏死病毒(Infectious hematopoietic necrosis virus,IHNV)感染的细胞悬液克隆病毒的糖蛋白基因,将其亚克隆至原核表达载体pCWori,转化到大肠杆菌DH 5α,通过发酵大肠杆菌制备病毒糖蛋白.经SDS-PAGE分析,诱导表达的重组蛋白主要以包涵体的形式存在,使用Ni-NTA亲和层析柱在变性条件下进行纯化并透析复性,最终得到了较高纯度的可溶性糖蛋白,分子量约为57 kDa.Western-blot分析结果显示,所表达的蛋白能够被IHNV病毒制备的兔抗IHNV血清识别.用复性后的蛋白免疫小鼠制备抗血清,ELISA显示抗体效价可达1∶64 000.经制备的抗血清可以作为一抗建立ELISA检测方法,用于检测细胞悬液的病毒粒子,将抗血清稀释到1∶16 000仍能与IHNV全病毒发生反应.本研究利用重组的IHNV糖蛋白成功制备了高效价的抗血清,并能够与IHNV全病毒发生特异性结合,为IHNV免疫学检测方法建立奠定了基础.     

草鱼呼肠孤病毒Ⅱ型VP6蛋白多克隆抗体制备及其特异性分析

为了制备高效的草鱼呼肠孤病毒Ⅱ型VP6蛋白多克隆抗体并对其特异性进行鉴定,实验以草鱼呼肠孤病毒Ⅱ型HZ08株为模板,采用PCR方法扩增S9基因,将该S9基因与p ET-32a(+)载体连接构建p ET-32a-S9原核表达载体,转化到大肠杆菌BL21(DE3)后用IPTG诱导表达;纯化后的重组VP6蛋白免疫新西兰兔,制备多克隆抗体,使用间接ELISA方法测定抗体效价,Western blot和IFA试验鉴定抗VP6蛋白多克隆抗体特异性。结果显示草鱼呼肠孤病毒Ⅱ型的S9基因在原核表达载体中能够正确地表达VP6蛋白,纯化的重组蛋白免疫新西兰兔制备的抗VP6多克隆抗体,经间接ELISA方法测定其效价约为1∶105,Western blot和IFA试验结果显示制备的多克隆抗体能特异性识别GCRVⅡ型毒株,而不能识别GCRV I型、Ⅲ型以及其它病毒,表明该多克隆抗体具有较高的特异性。研究表明制备的抗VP6蛋白多克隆抗体能够特异性识别GCRVⅡ型病毒,为GCRVⅡ型病原学研究及草鱼出血病临床诊断奠定基础。     

传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统构建

根据传染性胰腺坏死病毒(IPNV)VP3蛋白的全基因序列,设计并合成引物,以IPNV(ATCC VR-1318)细胞培养毒提取的核酸为模板,对传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统进行了构建研究。结果显示:进行RT-PCR扩增得到截短的VP3基因约615 bp目的片段,将其克隆到pMD18-T Simple载体,经酶切、PCR扩增和序列测定后显示目的片段正确;将目的片段分别亚克隆到乳酸菌细胞表面表达型载体和分泌表达型载体,电转化于干酪乳杆菌,获得了阳性重组菌株。结果表明,通过本实验方法可构建表达传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统,为实现IPNV VP3蛋白在乳酸菌中的表达及免疫原性研究奠定了基础。     

传染性造血组织坏死病毒核衣壳蛋白的原核表达及抗原性分析

应用RT-PCR方法扩增了长度为1176 bp的IHNV-ZYX株编码核衣壳(N)蛋白基因,将N基因克隆至原核表达载体pET30b,并在大肠杆菌Rosetta(DE3)中得到了表达.通过SDS-PAGE分析表明,重组菌诱导后得到了预期大小约48 KD的N蛋白,与理论值相符;提取N蛋白的包涵体,并制备抗血清.间接ELIS...     

传染性造血器官坏死病毒抗原表位富集区的原核表达及应用

以传染性造血器官坏死病毒Sn1203株(IHNV-Sn1203)基因组RNA提取物为模板,利用生物信息学软件分析,通过RT-PCR一步法扩增截短的G蛋白基因序列(约375 bp),将其克隆到表达载体p ET-27b中,构建重组表达质粒p ET-27b-IHNV-short G,通过大肠杆菌Rosetta表达菌株获得高效表达。在IPTG浓度为0.25 mmol/L时,37℃诱导表达,经SDS-PAGE电泳分析显示目的蛋白相对分子质量约为14 000,符合预期大小,并以包涵体的形式表达,4 h时目的蛋白表达量最大。蛋白经变性、复性处理后获得不带任何标签的纯化蛋白,并利用该蛋白制备兔抗血清。ELISA结果显示,兔抗血清的效价为1∶80 000,说明制备的兔抗血清能够识别表达的重组蛋白;间接免疫荧光结果表明兔抗G蛋白血清具有良好的特异性,并且与VHSV参考毒株没有任何交叉反应。     

虹鳟IgM重链恒定区的表达及兔抗血清的制备

为了能够成功表达虹鳟IgM,本研究利用生物信息学软件对虹鳟IgM的亲水性及抗原性进行了分析,根据GenBank收录的虹鳟IgM重链恒定区,参照生物信息学分析结果,设计用于扩增截短的IgM基因的引物,以虹鳟头肾RNA提取物为模板,利用RT-PCR方法扩增虹鳟截短的IgM重链恒定区部分基因片段,连接原核表达载体pET-27b,利用大肠杆菌Rosetta进行表达。SDS-PAGE及HPLC结果显示,纯化后截短的IgM大小约为47.7 ku,且纯度达到90%。利用其制备兔抗血清后ELISA分析结果显示,所制备的兔抗血清与本研究所表达的截短IgM蛋白的反应效价为1∶40 000,与虹鳟血清提取的全长IgM反应效价为1∶20 000并且呈现出抗原计量依赖性。研究表明,重组IgM蛋白与虹鳟血清中的天然IgM重链恒定区具有近似的结构,利用其所制备的兔抗血清能够与虹鳟鱼体中的天然IgM发生特异性反应。     

传染性胰腺坏死病毒VP2COE蛋白单克隆抗体的制备及与初步应用

为制备抗IPNV VP2蛋白的单克隆抗体,对其基本特性进行鉴定并进行初步应用。实验利用Ni-NTA亲和层析纯化的IPNV VP2 COE重组蛋白作为免疫原,免疫8周龄的雌性BALB/c小鼠,经3次免疫后,将免疫小鼠的脾细胞与骨髓瘤SP2/0细胞融合。采用间接ELISA和有限稀释法筛选杂交瘤细胞,共得到2株能稳定分泌特异性抗体的阳性细胞株,分别命名为5G10和5F3,亚类鉴定均为IgG1亚类。2株杂交瘤细胞的染色体数目在75～120之间。间接ELISA检测5G10和5F3细胞培养上清的效价分别为1∶105、1∶102,腹水效价分别为1∶108、1∶104。Western-blotting和间接免疫荧光鉴定结果显示,2株单抗均能特异性地识别IPNV。间接ELISA表明,2株单抗不与IHNV、VHSV、SVCV、HRV等病毒反应,说明获得的单抗具有高度的特异性。相加ELISA实验结果显示,2株单克隆抗体分别识别IPNV VP2蛋白上不同的抗原位点。应用间接免疫荧光方法对临床确定为患有IPN虹鳟肝组织进行检测,结果证实该2株单克隆抗体可用于后续实验。     

紫贻贝LC3B蛋白的原核表达及抗血清制备

LC3B是检测自噬程度的标志性分子,但是在低等动物体内缺少特异性强的LC3B抗体。为研究贝类的自噬性细胞死亡,本研究通过将紫贻贝的LC3B编码序列克隆到pET-32a原核表达载体中构建重组表达载体,进而对IPTG诱导浓度、诱导表达时间进行摸索;采用亲和层析对重组蛋白进行纯化,并采用SDS-PAGE检测及Western blot进行验证;利用获得的重组蛋白免疫新西兰兔,制备其多克隆抗体。结果显示,在20℃,转速为150 r/min条件下,当IPTG浓度为0.6 mmol/L,诱导表达10 h后,可以得到高表达量、可溶性的重组MgLC3B-His融合蛋白,亲和层析纯化后,获得单一条带的MgLC3B-His可溶性重组蛋白;采用纯化后的MgLC3B-His融合蛋白对新西兰兔进行多次免疫,采集分离兔抗血清并利用protein A纯化,获得紫贻贝的LC3B多克隆抗体,效价为25 600。紫贻贝LC3B多克隆抗体的成功制备,为今后深入开展紫贻贝及相近物种的细胞自噬研究奠定了基础。     

罗非鱼源无乳链球菌兼职蛋白EF-Tu的克隆、表达及其抗原性检测

为检测罗非鱼源无乳链球菌兼职蛋白EF-Tu(延伸因子Tu,Elongation Factor Tu)的抗原性,本实验克隆了罗非鱼源无乳链球菌HN0303的EF-Tu基因序列,并进行了蛋白相关性质的预测和系统发育树的构建。通过原核表达得到EF-Tu重组蛋白,同时利用纯化的蛋白免疫家兔获得多克隆兔抗EF-Tu重组蛋白血清以用于EF-Tu蛋白抗原性检测。结果显示,罗非鱼源无乳链球菌HN0303 EF-Tu基因有1个由1197个碱基组成的ORF,编码398个氨基酸。生物信息学分析显示其分子式为C_(1933)H_(3096)N_(532)O_(615)S_(11),分子质量为43.981 ku,理论等电点为4.749;具有多个磷酸化位点,不具有信号肽和跨膜区域;具有保守的EFTu结构域、EF-Tu-II结构域和EF-Tu-Ⅲ结构域,且与其他来源无乳链球菌的EF-Tu蛋白具有很高的同源性;具有较高的抗原指数,表明其可形成多个抗原表位。SDS-PAGE检测发现,诱导表达的重组蛋白以包涵体的形式出现在沉淀中,大小约为66.4 ku。Western Blot分析表明,兔抗EF-Tu重组蛋白血清能分别特异性结合菌体蛋白和EF-Tu重组蛋白。同时使用兔抗EF-Tu重组蛋白血清封闭罗非鱼源无乳链球菌HN0303表面的EF-Tu蛋白后,无乳链球菌HN0303粘附EPC(Epithelioma papulosum cyprini,鲤鱼上皮细胞)的能力下降了79.99%±2.43%。本研究表明,原核表达的罗非鱼源无乳链球菌EF-Tu重组蛋白具备较好的抗原性,用其制备的兔抗血清能够较好地抑制罗非鱼源无乳链球菌的粘附,推测其可能为罗非鱼源无乳链球菌亚单位疫苗的候选蛋白。     

传染性胰腺坏死病毒VP3基因的分段表达及其抗原表位区域分析

采用PCR方法克隆了传染性胰腺坏死病毒(IPNV) VP3四段相互重叠的基因片段L1、L2、L3和L4,将PCR产物分别连接到原核表达载体pGEX-6P1和pET32a上,经酶切、PCR、测序鉴定,获得重组质粒pGEX-6P1 -VP3(L1)、pET32a-VP3( L2)、pGEX-6P1-VP3( L3)和pGE...     

Antigenic diversity of eastern Canadian isolates of infectious pancreatic necrosis virus

A collection of infectious pancreatic necrosis virus (IPNV) isolated in five provinces of eastern Canada was analysed by an antigen-coated immunosorbent assay and by neutralization tests using selected monoclonal and polyclonal antibodies. Relevant antigenic sites of the two major capsid proteins, VP2 and VP3, were simultaneously compared. The A1 serotype was predominant and no significant variations of VP2 epitopes were observed. However, two subtypes could be distinguished on the basis of one or two epitopes on VP3. Other serotypes such as A6, A7 or A8 have been detected in piscicultures of New Brunswick and Nova Scotia. The antigenic characterization of IPNV strains appears of interest for epidemiological studies.     

抗传染性胰腺坏死病毒VP3蛋白单克隆抗体的制备

利用纯化后的传染性胰腺坏死病毒(IPNV VP3)重组蛋白免疫BALB/c小鼠,通过细胞融合技术,采用间接ELISA和有限稀释法筛选杂交瘤细胞,利用染色体鉴定、蛋白印迹和免疫荧光等方法对单克隆抗体进行鉴定,共得到2株能稳定分泌特异性抗体的阳性细胞株,分别命名为2F1、4A7,亚类鉴定2株单抗均为IgG1亚类。ELISA检测其腹水效价,蛋白印迹检测表明获得的2株单抗均能特异性识别IPNV VP3蛋白;间接免疫荧光鉴定表明2株单抗均与IPNV发生反应;间接ELISA检测结果表明2株单抗均不与HSV、SVCV、HRV等病毒反应,与IPNV具有较强的特异性反应。     

Involvement of serine proteinase in infectious pancreatic necrosis virus capsid protein maturation and NS proteinase cleavage in CHSE-214 cells

An investigation of virus-specific protein maturation in infectious pancreatic necrosis virus (IPNV) infected Chinook salmon embryo cells (CHSE-214) was undertaken. The precursor protein (pVP2-1) of the major mature capsid protein (VP2) was processed sequentially from pVP2-1 to pVP2-2 and VP2. Experiments using serine proteinase inhibitors showed that the maturation of the VP2 was blocked in the pVP2-1 post-translational cleavage steps. A protinin, a potent proteinase inhibitor, at 800 μg ml(-1) blocked pVP2-2 to VP2 and the cleavage of VP4 (28 kDa) to VP4-1 (25 kDa). Therefore, our data showed that the maturation of the capsid protein (VP2) and cleavage of VP4 (NS proteinase) can be blocked by serine proteinase inhibitors.     

Infectious pancreatic necrosis virus (IPNV) serotype Sp is prevalent in Turkish rainbow trout farms

Infectious pancreatic necrosis virus (IPNV) is a common pathogen of rainbow trout (Oncorhynchus mykiss) in Turkey. We found that 455 of 1,676 sample pools tested were IPNV positive. Positive samples were found in all geographical regions where sampling was conducted. Sequence and phylogenetic analyses of VP2 from 30 isolates representing all regions showed that the viruses were highly similar in sequence and grouped within Genogroup 5 (serotype Sp‐A2). No correlations between sequences, sampling sites or geographical origins were identified. Although clinical disease was evident in several farms, analyses of the amino acid sequence of VP2 showed that all virus strains harboured the P₂₁₇T₂₂₁ motif, assumed to be associated with low virulence. We conclude that IPNV is prevalent in Turkish rainbow trout farms and that the viruses are very homogenous and likely to be of European origin. Frequent exchange of eggs and live fish within the farming industry may explain the homogeneity of the IPNV.     

Antigenic analysis of reference strains and Norwegian field strains of aquatic birnaviruses by the use of six monoclonal antibodies produced against the infectious pancreatic necrosis virus N1 strain

Abstract. Six monoclonal antibodies (MAbs) produced against the infectious pancreatic necrosis virus (IPNV) N1 strain were used in a dot-blot assay to examine reference strains of the nine proposed serotypes and a representative selection of 81 Norwegian aquatic birnavirus isolates. These isolates had earlier been serotyped by use of a panel of 11 MAbs produced against other strains of IPNV. Correlations between the reaction patterns of the two panels of MAbs were found. All reference strains and field isolates shared two epitopes, one on VP2 and one on VP3. Seventy-seven of the field isolates reacted identically with the N1 strain (positive with all six MAbs). The Sp type strain was positive with five of the MAbs and was different from all the field strains. The other reference strains (WB, VR299, Ab, Ja, Te, He, C1, C2 and C3) were positive with two to four of the MAbs. Together with previously published data, these findings indicate that most Norwegian isolates are closely related to, or identical with, the N1 strain and belong to the Sp serotype. No correlation between the health status of Atlantic salmon and antigenicity of the isolates was found. Testing of the reference strains in ELISA revealed some discrepancies with the dot-blot results.     

Immunity induced by recombinant attenuated IHNV (infectious hematopoietic necrosis virus)‐GN438A expresses VP2 gene‐encoded IPNV (infectious pancreatic necrosis virus) against both pathogens in rainbow trout

Infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) are important pathogens in rainbow trout farming worldwide. Their co‐infection is also common, which causes great economic loss in juvenile salmon species. Development of a universal virus vaccine providing broadly cross‐protective immunity will be of great importance. In this study, we generated two recombinant (r) virus (rIHNV‐N438A‐ΔNV‐EGFP and rIHNV‐N438A‐ΔNV‐VP2) replacing the NV gene of the backbone of rIHNV at the single point mutation at residue 438 with an efficient green fluorescent protein (EGFP) reporter gene and antigenic VP2 gene of IPNV. Meanwhile, we tested their efficacy against the wild‐type (wt) IHNV HLJ‐09 virus and IPNV serotype Sp virus challenge. The relative per cent survival rates of two recombinant viruses against (wt) IHNV HLJ‐09 virus challenge were 84.6% and 81.5%, respectively. Simultaneously, the relative per cent survival rate of rIHNV‐N438A‐ΔNV‐VP2 against IPNV serotype Sp virus challenge was 88.9%. It showed the two recombinant viruses had high protection rates and induced a high level of antibodies against IHNV or IPNV. Taken together, these results suggest the VP2 gene of IPNV can act as candidate gene for vaccine and attenuated multivalent live vaccines and molecular marker vaccines have potential application for viral vaccine.