Immunogenic and protective properties of rabies virus glycoprotein expressed by baculovirus vectors

The gene encoding the glycoprotein of rabies virus (G protein, CVS strain) has been cloned and inserted into the baculovirus transfer vector pAcYM1 derived from the nuclear polyhedrosis virus of Autographa californica (AcNPV). The gene was placed under the control of the AcNPV polyhedrin promoter and expressed to high levels by the derived recombinant virus using a Spodoptera frugiperda cell line. It has been established that the antigenic characteristics of the protein were conserved by comparison with those of the native glycoprotein of rabies virions. The immunogenicity of the expressed product was also demonstrated. Intraperitoneal or intramuscular injection of G antigen conferred protection to mice and was associated with the induction of high titers of neutralizing antibodies. The availability of large quantities of antigenically and immunogenically reactive rabies G protein may make feasible crystallographic studies and the safe preparation of a low cost subunit vaccine for the disease.     

Use of hybridoma monoclonal antibodies in the detection of antigenic differences between rabies and rabies-related virus proteins. II. The glycoprotein

Twenty-five hybridoma cultures secreted monoclonal antibodies directed against the glycoprotein of rabies or rabies-related viruses. The antibodies had different specificities for the glycoproteins of eight rabies and rabies-related viruses. They could be classified into fourteen groups which probably correspond to different antigenic determinants on the glycoproteins. These hybridomas when used in either radioimmunoassay (RIA) or in neutralization tests allow differentiation of laboratory strains of rabies virus from each other as well as from the rabies-related viruses.     

Characterization of rabies virus glycoprotein expressed by recombinant baculovirus.

A cDNA of the glycoprotein (G protein) gene of rabies virus Nishigahara strain was cloned and inserted into a baculovirus genome under the control of the polyhedrin promoter. Infection of Spodoptera frugiperda cells with this recombinant virus produced a large quantity of new protein instead of the parental polyhedrin protein. By immunofluorescent and immunoblotting analyses, the recombinant protein was antigenically similar to the authentic G protein. Its molecular mass estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, however, was slightly smaller than that of the authentic one, and this observation was suggested to be due to the difference in glycosylation level between the two G proteins. The recombinant G protein expressed on the cell surface of the insect cells showed a fusion activity at low pH. The fusion activity was inhibited by antiserum against either whole virions or G protein of rabies virus.     

Genetic and antigenic typing of rabies virus in Chile. Brief report

Summary.  Forty-one isolates of rabies virus from insectivorous bats and one from a domestic cat in Chile, were characterized using eight anti-nucleoprotein monoclonal antibodies (N-Mabs) and by nucleotide sequence analysis. Thirty-two isolates were identified as antigenic variant 4 associated with Tadarida brasiliensis bats, twenty-eight were genetically associated with variant Tadarida brasiliensis and four with Lasiurus sp. bats. One isolate was identified as antigenic variant 3 associated with Desmodus rotundus bats, and by genetic analysis was identified as variant Myotis sp. bat. Eight isolates were unrelated to any antigenic variant, and they were identified as a genetic variant associated with Histiotus sp. bats. These antigenic and genetic characterizations may establish epidemiological links between rabies cases and increase the understanding of rabies epidemiology in this country. Received January 2, 2002; accepted July 22, 2002     

Antigenic variation in rabies virus strains

Several rabies virus isolates from small wild rodents, one strain isolated from a fox and another from a cat, as well as the CVS strain were compared in cross-protection and virus-neutralization tests. Antigenic variations between the strains and between different batches of individual strains were found. These antigenic differences could not be explained by denaturation caused by UV irradiation or deep-freeze storage, by the presence of "incomplete" particles or by passage in immune organism. An antigenic difference was batch-specific and was only demonstrable on comparison with a relatively large number of strains: it has probably developed during the assembly of antigenic determinants of the virion. There was no correlation between protective and virus-neutralizing activities.     

Putative antigenic domains in glycoprotein G of rabies virus: Is the RGK sequence involved in virus adsorption to cellular receptors?

Computer analysis of rabies virus glycoprotein G provides a means for identification of functional domains in the viral glycoprotein. The computer analysis suggested 22 putative antigenic domains, of which three are RG-containing amino acid sequences that might be involved in the binding of rabies virions to cellular receptors. Synthetic RG peptides may be able to interfere with rabies virus adsorption to cellular receptors.     

表达狂犬病毒糖蛋白的非复制型重组痘苗病毒的构建 …

目的 提高表达狂犬病毒糖蛋白（ＲＧ）的重组痘苗病毒的安全性。方法 将编码中国狂犬病毒５ａＧ株糖蛋白的基因,插入痘苗病毒天坛株的ＴＫ区,获得重组病毒ＶＴＫＲＧ,通过两步同源重组,删除ＣＫ片段间与痘苗病毒毒力及宿主范围相关的基因,得到非复制型重组痘苗病毒ＶＴＫＲＧΔＣＫ。结果 经ＰＣＲ鉴定,ＣＫ间的核酸片段被成功删除,其缺失性状能稳定地遗传。     

Isolation and purification of a polymeric form of the glycoprotein of rabies virus.

Of the three major proteins associated with the rabies virus membrane, only the glycoprotein was found to be located on the external surface of the virus membrane. Glycoprotein prepared by treatment of rabies virus with Triton X-100 and purified by isoelectric focusing was found to be homogeneous with respect to size and isoelectric point. This material, which is free of phospholipids, is able to protect in vaccination experiments against a lethal challenge infection with rabies virus. The apparent mol. wt. of this component isolated under non-denaturing conditions is approx. 400000. The same material analysed by SDS polyacrylamide gel electrophoresis (PAGE) was found to consist solely of polypeptide chains of the G protein (mol. wt. 80000). A minor glycoprotein (gp 50), detected by PAGE of the Triton X-100 released material, appeared to be a breakdown product of the G-protein. Therefore the detergent released material represents homopolymers of the G-protein. Whether the antigenic determinants reside on the monomeric subunit or are a property of the polymeric form of the G-protein is discussed.     

Conformation-dependent accessibility of the linear epitopes located on the rabies virus glycoprotein.

Seven monoclonal antibodies (MAbs) were derived from mice immunized with the rabies virus glycoprotein of the Pitman-Moore (PM) strain. These antibodies recognized at least five partially overlapping sites located in one immunodominant region. A panel of MAbs was then used to characterize antigenic relationship between PM strain and SAD-Vnukovo strain of these rabies viruses. In immunoblot, all tested antibodies bound to the glycoprotein of both rabies strains, indicating shared antigenic determinants located on the corresponding immunodominant regions. The pattern of reactivity in immunoblot suggested the specificity of antibodies against linear epitopes. However, the supposed close antigenic relation between PM and SAD-Vnukovo strains (evidenced by immunoblot) was not fully confirmed by immunoenzymatic assay. Data provided by ELISA demonstrated two distinct patterns of MAbs reactivity with both antigens. Four antibodies showed specificity for PM strain glycoprotein only, while three MAbs bound with both PM and SAD-Vnukovo strain antigens. We supposed the strain-specific conformation of the native glycoprotein to be responsible for selective access of single MAbs to the respective common linear epitopes.     

Membrane fusion activity, oligomerization, and assembly of the rabies virus glycoprotein.

The spike glycoprotein (G protein) of rabies virus (CVS strain) expressed in HeLa cells from cloned cDNA mediated membrane fusion after exposure to pHs of 6.1 or below. Chemical crosslinking showed that the rabies G protein, like the vesicular stomatitis virus (VSV) G protein, could be crosslinked to dimers and trimers, indicating that rabies G protein is a trimer. However, unlike the VSV G protein, rabies G protein trimers were not stable to sedimentation in sucrose gradients, even at a mildly acidic pH which stabilizes the VSV G protein trimers. In addition, we report that the expressed rabies virus G protein was functional because it could assemble into VSV particles (tsO45) lacking VSV G protein and rescue infectivity. These VSV (rabies) pseudotypes were neutralized only by an antibody to the rabies G protein. We also examined the properties of a hybrid protein containing the extracellular domain of the rabies virus glycoprotein and the transmembrane and cytoplasmic domains of the VSV G protein. This protein was transported to the cell surface and could be crosslinked to form dimers and trimers, but had little or no detectable membrane fusion activity. The lack of fusion activity was paradoxical because the hybrid protein could rescue VSV infectivity, although the titers were lower than those obtained with the wild-type rabies G protein.     

靶向PV株核蛋白基因的小分子干扰RNA对不同狂犬病病毒毒株复制的交叉抑制作用

目的研究小分子干扰RNA（siRNA）对狂犬病病毒（RV）不同毒株复制的交叉抑制效果。方法采用体外转录和RNA酶Ⅲ消化长片段双链RNA的方法制备8条以RV的PV株核蛋白（N）基因为靶基因的21nt siRNA，用以转染已经感染了不同滴度PV、CTN或CVS株RV的BSR细胞，采用直接免疫荧光法观察转染的siRNA对已感染BSR细胞的不同毒株RV复制的抑制效果，并分析这种抑制效果与靶基因序列的相关性。结果不同21nt siRNA均对PV株的复制产生了较强的抑制作用：对CTN株和CVS株的交叉抑制作用观察结果表明，21nt siRNA与靶基因在碱基错配高达5个的情况下仍对病毒复制保持抑制效应。然而，siRNA与靶基因碱基错配的位置与抑制作用的丧失高度相关。3’端第2个碱基的错配将使抑制作用表失，随后的碱基错配对抑制作用的影响依次降低；中部碱基错配影响较小；而5’端碱基错配对抑制作用几乎没有影响。结论siRNA对靶基因的抑制作用的丧失与其同靶基因序列碱基错配的位置相关，3’端碱基错配可降低其抑制作用的特异性，产生偏靶效应的范围和概率可能增大，这为设计独特的siRNA序列提供了新的思路。     

Immunization of foxes against rabies with a vaccinia recombinant virus expressing the rabies glycoprotein

Summary Foxes were vaccinated orally (by bait), gastrically (by stomach tube) and by sacrification with a vaccinia recombinant virus expressing the rabies glycoprotein. Neutralizing antibodies against rabies virus were detected at two weeks postvaccination in 8/8 foxes in the bait-fed group, in 3/6 foxes inoculated by stomach tube and in 2/2 of the scarified foxes. After challenge at three months postvaccination with street rabies virus, all foxes that had developed antibodies were protected. The high rate of seroconversion, high levels of antibodies, and resistance to challenge suggest that this recombinant virus might be a suitable vaccine for oral immunization of foxes against rabies.     

A phylogenetic study of new rabies virus strains in different regions of Iran

Virus Genes - Rabies is the most critical zoonotic disease in Iran, which imposes many extra costs on health care system in each country. The present study aimed to determine the molecular...     

狂犬病病毒糖蛋白和核蛋白基因的克隆及其重组蛋白在昆虫细胞中的表达

目的从国内狂犬病疫苗ａＧ株中克隆狂犬病病毒糖蛋白（ＧＰ）基因和核蛋白（ＮＰ）基因，应用杆状病毒－昆虫细胞表达系统使其在昆虫细胞中表达。方法从狂犬病病毒感染细胞上清液中提取病毒ＲＮＡ，应用ＲＴ－ＰＣＲ方法扩增ＧＰ基因和ＮＰ基因。扩增的基因与转移质粒连接并转化大肠杆菌，得到重组转移质粒。将其与野生杆状病毒（ＡｃＭＮＰＶ）线性ＤＮＡ共转染Ｓｆ９昆虫细胞，通过有限稀释法筛选含有ＧＰ基因和ＮＰ基因重组病毒。初步检测了重组蛋白的抗原性。结果用ＲＴ－ＰＣＲ方法扩增得到ＧＰ基因和ＮＰ基因，通过重组转移后重组病毒感染的细胞经免疫印染实验表明可分别表达ＧＰ和ＮＰ重组蛋白。重组蛋白的分子量分别为５８×１０３和５３×１０３。用重组病毒感染的细胞免疫小鼠后可诱导动物产生特异性抗体。结论可以应用杆状病毒－昆虫细胞表达系统表达狂犬病病毒ＧＰ和ＮＰ重组蛋白，为开发基因工程化狂犬病疫苗提供有意义的资料     

狂犬病病毒糖蛋白真核表达质粒的构建及免疫原性的初步研究

目的 构建狂犬病病毒糖蛋白基因DNA真核表达质粒,并检测其免疫原性.方法 用RT-PCR法扩增和分离CTN株狂犬病病毒糖蛋白基因,测序后克隆至pcDNA5.0载体,构建重组质粒pcDNA5.0-G,提取质粒,转化293T细胞,检测糖蛋白瞬时表达,并以该重组质粒肌肉注射免疫BALB/c小鼠,狂犬病病毒CVS株攻击,观察小鼠存活情况.结果 酶切、测序结果显示重组质粒pcDNA5.0-G构建成功,瞬时表达结果显示糖蛋白获得大量表达.经肌肉注射质粒常规免疫小鼠,病毒攻击后小鼠保护率为73.3％,对照组为6.7％.结论 所构建狂犬病病毒糖蛋白真核表达质粒pcDNA5.0-G经肌肉注射免疫后可有效保护小鼠免受狂犬病病毒攻击,具有良好的免疫原性,这为后期核酸疫苗的研发奠定基础.     

Population structure of some street rabies virus strains

Summary Street rabies virus strains can contain from one to three biological (clinical) variants as it has been estimated using random bred white mice and dogs.     

狂犬病毒糖蛋白及核蛋白在非复制型痘苗病毒天坛株中的共同表达

目的　提高重组痘苗病毒狂犬疫苗的有效性和安全性。方法　利用TK区表达狂犬病毒糖蛋白 (RG)的重组痘苗病毒作为亲本株 ,通过两步同源重组 ,删除痘苗病毒基因组CK片段间与毒力和宿主范围相关的核酸片段 ,同时将狂犬病毒核蛋白 (RN)基因插入C K片段之间 ,获得了含有RG基因和RN基因的非复制型重组痘苗病毒VTKRGΔCKLacZRN。结果　经PCR鉴定 ,RN基因已插入CK区 ;Westernblot结果显示 ,该株病毒能同时表达RG和RN ,相对分子质量 (Mr)分别为 6 5× 10 3 和 5 0 5× 10 3。VTKRGΔCKLacZRN在人源细胞如TK 143细胞中不能正常繁殖 ,在鸡胚成纤维细胞 (CEF)中能正常复制。与非复制型重组病毒VTKRGΔCK相比 ,VTKRGΔCKLacZRN免疫小鼠后能更快地诱生较高滴度的中和抗体 ,效果相当于复制型重组病毒VTKRG免疫组 ;它们均能保护小鼠针对致死剂量狂犬病毒国际标准攻击毒株 (CVS)的攻击。结论　VTKRGΔCKLacZRN具有良好的免疫效果和安全性     

Raccoon poxvirus rabies virus glycoprotein recombinant vaccine in sheep

Summary Twenty sheep were divided into groups and inoculated by various routes with recombinant raccoon poxvirus expressing the CVS rabies virus glycoprotein (rRCNV-G) or with raccoon poxvirus (RCNV). The apparent innocuous pathologic responses to each virus coupled with development of high levels of rabies virus neutralizing antibodies in animals vaccinated with rRCNV-G intradermally or intramuscularly suggested that the recombinant is effective and that RCNV would be a suitable substrate for further development of sheep vaccines. Poor antibody response to rRCNV-G given orally implied that it would be relatively harmless if inadvertently ingested by sheep. Virus transmission between vaccinated and sentinel sheep was not observed or detected serologically.