关键词： 急性弛缓性麻痹   疫苗衍生脊灰病毒  

摘要： 分析脊髓灰质炎(脊灰)病毒(PV)的急性弛缓性麻痹(AFP)病例流行病学特征,提高对疫苗衍生脊灰病毒(VDPVs)和循环的疫苗衍生脊灰病毒(cVDPVs)的认识,增加AFP病例监测系统敏感性。对西安市1995-2008年检出的PV阳性AFP病例进行流行病学分析。对疫苗变异PV采用VP1基因核苷酸序列测定方法进行分子生物性状分析。西安市1995-2008年共检出PV13株,检出率4.29%。分离到的PV以II、III型为主,AFP病例散在发生,无聚集性。未全程免疫儿童(全程免疫儿童,年龄以≤1岁儿童为主(84.62%)。麻痹残留率高达84.62%。脊灰相关病例(VAPP)的发生危险性为0.24/100万。型内特征鉴定有1株为疫苗变异PV,经VP1基因核苷酸序列测定未达到VDPV的分类标准。维持无脊灰阶段,存在着VDPV和发生cVDPVs的可能,在保持高水平脊髓灰质炎疫苗(OPV)免疫覆盖率的同时,高质量的AFP病例流行病学监测和病毒学监测工作,具有重要的现实意义。

关键词： 原发性免疫缺陷   疫苗衍生脊髓灰质炎病毒  

摘要： 随着全球消灭脊髓灰质炎(脊灰)活动进入到最后阶段,世界各地陆续发现了多例免疫缺陷病患者排出的疫苗衍生脊灰病毒(Vaccine-derived Poliovirus,VDPV)。由于此类病例能够长期携带并向环境中排出VDPV,各国开始关注免疫缺陷病患者排出PV的问题,并对消灭脊灰后的免疫策略重新进行思考。

关键词： 口服脊髓灰质炎减毒活疫苗(人二倍体细胞)   安全性   免疫原性  

摘要： 目的评价口服脊髓灰质炎(脊灰)减毒活疫苗(人二倍体细胞)[Oral Poliomyelitis Attenuated Live Vaccine(Human Diploid Cell),OPV(HDC)],在≥2月龄儿童中的安全性和免疫原性。方法采用随机、盲态、对照的原则进行设计,1200名2～5月龄婴儿随机接种OPV(HDC)和对照疫苗,用抗脊灰病毒中和抗体试验检测免疫前、后抗体。结果接种3剂OPV(HDC)后全身反应轻微,全程免疫后1个月,Ⅰ、Ⅱ、Ⅲ型中和抗体免疫成功率分别为98.28%、95.32%、95.34%;免疫后易感人群的Ⅰ、Ⅱ、Ⅲ型中和抗体几何平均滴度,分别为1∶1243.72、1∶234.38、1∶273.10。结论 OPV(HDC)在≥2月龄儿童中具有良好的安全性和免疫原性。

关键词： 脊髓灰质炎病毒   抗体   单克隆   酶联免疫吸附测定  

摘要： 目的制备抗脊髓灰质炎病毒单克隆抗体,为ELISA检测方法的建立奠定基础。方法将Ⅰ型脊髓灰质炎减毒疫苗原液和灭活疫苗原液经超滤、超离纯化,以纯化的减毒脊髓灰质炎病毒D抗原免疫BALB/c小鼠,得到的脾细胞与SP2/0-A14小鼠骨髓瘤细胞融合,以纯化的灭活脊髓灰质炎病毒D抗原建立间接ELISA法,筛选分泌特异性单抗的阳性细胞株,诱生小鼠腹水,通过正辛酸-硫酸铵法纯化抗体,并进行各项鉴定。结果获得两株稳定分泌抗脊髓灰质炎病毒单抗的细胞株7G5及5E4。纯化的7G5和5E4株单抗分别可与脊髓灰质炎病毒D抗原的VP2、VP3衣壳蛋白结合;在不同温度下放置均比较稳定;pH4不利于7G5株单抗的保存;5E4株单抗的相对亲和力大于7G5株;7G5株单抗的亚类为IgM,5E4株单抗的亚类为IgG2a;两株单抗可识别相似表位;7G5株和5E4株单抗的中和效价分别为1:64和1:128。结论已成功制备了两株分泌抗脊髓灰质炎病毒的单抗。

关键词： 转人脊髓灰质病毒受体基因的小鼠肺细胞系(L20B细胞)   柯萨奇A组病毒   脊髓灰质炎病毒分离率  

摘要： 目的鉴定L20B细胞[转人脊髓灰质炎(脊灰)病毒受体基因的小鼠肺细胞系]支持生长的非脊灰肠道病毒(Non-polio Enteroviruses,NPEV)的血清型,并分析病毒基因特征,探讨其对脊灰病毒(Poliovirus,PV)分离率的影响。方法收集宁夏回族自治区从健康人群和广西壮族自治区从急性弛缓性麻痹病例粪便标本中分离的5株L20B细胞支持生长的NPEVs,对病毒分离物采用逆转录-聚合酶链反应进行VP4编码区基因扩增和核苷酸序列测定和分析,根据序列比对结果确定血清型,再进行全长VP1编码区序列测定和分析,并和基因数据库下载的相应血清型NPEVs的VP1编码区核苷酸序列进行比对和分析,构建基因亲缘性关系树。结果 5株NPEVs均鉴定为柯萨奇A组病毒(Coxsackie Virus GroupA,CVA),其中1株为CVA4,另1株为CVA8,其余3株均为CVA10,均属A组人肠道病毒(Human Enteroviruses,HEV);通过比较全长VP1编码区核苷酸同源性和构建亲缘关系树发现,3个血清型的中国分离株都分别独立成簇,与其他国家分离的相应血清型的NPEVs及原型株病毒差异都较大,是本土流行病毒株。结论所研究的L20B细胞支持生长的5株NPEVs均属A组HEV,包括CVA4、CVA8、CVA10三个血清型。由于L20B细胞对PV的最初接种具有很高的敏感性,因此L20B细胞即使支持某些CVA生长,也不会影响PV分离率。但在近年来中国发生较大规模手足口病(Hand,Foot and Mouth Disease,HFMD)的背景下,由于这些A组HEV同时是HFMD的病原体,对这些病毒的鉴定对PV的鉴别诊断和HFMD的预防控制都有实际意义。

关键词： Poliovirus   Recombinant   Genome   Capsid   Evolution  

摘要： The genetic and phenotypic characterization of poliovirus strain P3/Jinan/1/09, isolated from sewage sample in Jinan city, Shandong province, China, was described. The strain had a Sabin type 3/type 2/type 3 recombinant genome, with the first crossover site located in capsid VP1 coding region between nucleotide positions 3293 and 3294 (numbering according to Sabin 3), and the second crossover site in 3D region between positions 6374 and 6378. The recombinant had introduced six Sabin 2-derived amino acids into the carboxyl terminus of Sabin 3 VP1 capsid protein. The complete genome of the isolate revealed eight nucleotide substitutions in Sabin 3 region with two substitutions resulting in amino acid alteration, and two missense substitutions in the Sabin 2 region. An estimation based on the evolution rate of the P1 coding region of Sabin 3 background suggested that evolution time of strain P3/Jinan/1/09 might be 76-80 days. The person who excreted the recombinant was not known and no evidence was obtained for its circulation in population via acute flaccid paralysis surveillance. The virus showed Sabin 3 serological characterization in neutralization test, and it did not lose temperature sensitivity phenotype at 40 degrees C. The significance of environmental surveillance and the presence of natural capsid recombinant poliovirus strain in the context of the global polio eradication initiative are discussed. (C) 2010 Elsevier B.V. All rights reserved.

关键词： RNA synthesis   RNA structure   Poliovirus   Viral structure   Viral replication   Luciferase   Viral genomics   Protein translation  

摘要： RNA structures present throughout RNA virus genomes serve as scaffolds to organize multiple factors involved in the initiation of RNA synthesis. Several of these RNA elements play multiple roles in the RNA replication pathway. An RNA structure formed around the 5'-end of the poliovirus genomic RNA has been implicated in the initiation of both negative- and positive-strand RNA synthesis. Dissecting the roles of these multifunctional elements is usually hindered by the interdependent nature of the viral replication processes and often pleiotropic effects of mutations. Here, we describe a novel approach to examine RNA elements with multiple roles. Our approach relies on the duplication of the RNA structure so that one copy is dedicated to the initiation of negative-strand RNA synthesis, while the other mediates positive-strand synthesis. This allows us to study the function of the element in promoting positive-strand RNA synthesis, independently of its function in negative-strand initiation. Using this approach, we demonstrate that the entire 5'-end RNA structure that forms on the positive-strand is required for initiation of new positive-strand RNAs. Also required to initiate positive-strand RNA synthesis are the binding sites for the viral polymerase precursor, 3CD, and the host factor, PCBP. Furthermore, we identify specific nucleotide sequences within "stem a'' that are essential for the initiation of positive-strand RNA synthesis. These findings provide direct evidence for a trans-initiation model, in which binding of proteins to internal sequences of a pre-existing positive-strand RNA affects the synthesis of subsequent copies of that RNA, most likely by organizing replication factors around the initiation site.

关键词： Vaccine-derived poliovirus   Recombination   RT-PCR screening analysis  

摘要： In the post-eradication era of wild polioviruses, the only remaining sources of poliovirus infection worldwide would be the vaccine-derived polioviruses (VDPVs). As the preponderance of countries certified to be polio-free has switched from OPV (oral poliovirus vaccine) to IPV (inactivated poliovirus vaccine), importation of recombinant evolved derivatives of vaccinal strains would have serious implication for public health. To test the robustness of the proposed RT-PCR screening analysis, eleven recombinant vaccine-derived polioviruses that were characterized previously by sequencing by our group, in addition to three recently identified recombinant environmental isolates were assayed. Although the most definitive characterization of VDPVs is by genomic sequencing, in this study we describe a new, inexpensive and broadly applicable RT-PCR assay for the identification of the predominant recombination types S3/Sx in 2C and S2/Sx in 3D genomic regions respectively of VDPVs, that can be readily implemented in laboratories lacking sequencing facilities as a first approach for the early detection of vaccine-derived poliovirus (VDPVs). (C) 2009 Elsevier Ltd. All rights reserved.

关键词： virus replication   cytopathic effect   RNA replication activity   Cytopathic effect   Virus Replication   orbit maneuvering engines(space shuttles)   Polydnaviridae   delta   Delta  

摘要： Poliovirus (PV) 2A(pro) has been considered important for PV replication and is known to be toxic to host cells. A 2A(pro)-deficient PV would potentially be less toxic and ideal as a vector. To examine whether 2A(pro) is needed to form progeny virus, a full-length cDNA of dicistronic (dc) PV with (pOME) or without (pOME Delta 2A) 2A(pro) was constructed in the strain PV1(M)OM. RNAs of both pOME and pOME Delta 2A were capable of forming progeny viruses, called OME and OME Delta 2A, respectively. In their ability to induce a cytopathic effect (CPE), the strains ranked as OME Delta 2A < OME is approximately equal to PV1(M) OM. These results suggest that 2A(pro) is not essential for full-length dc PV to form progeny virus and that it contributes to the efficient viral replication and/or induction of a CPE. To clarify whether 2A(pro) is essential for P1-null (lacking the entire coding sequence for capsid proteins) PV, the RNA replication activity of P1-null PV (pOM Delta P1) or P1-null PV without 2A(pro) (pOM Delta P1 Delta 2A) or without both 2A(pro) and 2B (pOM Delta P1 Delta 2A Delta 2B) was examined. The RNAs of pOM Delta P1 and pOM Delta P1 Delta 2A could replicate and form progeny viruses under a trans supply of P1 protein, whereas the RNA of pOM Delta P1 Delta 2A Delta 2B could not. These results suggest that 2A(pro) is not needed for the replication of P1-null PV, although it is important for PV RNA replication and inducing a CPE. To know whether a 2A(pro)-deficient PV can be used as a vector, a P1-null PV containing the enhanced green fluorescent protein (EGFP) coding sequence with or without 2A(pro) was examined. It expressed fluorescent protein. This result suggests that 2A(pro)-deficient PV can express foreign genes.

关键词： Infants   Vaccination and immunization   Immune response   Cytokines   Vaccine development   Birth weight   Seasons   Vaccines  

摘要： Background: Oral polio vaccine (OPV) is recommended to be given at birth together with BCG vaccine. While we were conducting two trials including low-birth-weight (LBW) and normal-birth-weight (NBW) infants in Guinea-Bissau, OPV was not available during some periods and therefore some infants did not receive OPV at birth, but only BCG. We investigated the effect of OPV given simultaneously with BCG at birth on the immune response to BCG vaccine. Methods and Findings: We compared the in vitro and the in vivo response to PPD in the infants who received OPV and BCG with that of infants who received BCG only. At age 6 weeks, the in vitro cytokine response to purified protein derivate (PPD) of M. Tuberculosis was reduced in LBW and NBW infants who had received OPV with BCG. In a pooled analysis receiving OPV with BCG at birth was associated with significantly lower IL-13 (p = 0.041) and IFN-gamma (p = 0.004) and a tendency for lower IL-10 (p = 0.054) in response to PPD. Furthermore, OPV was associated with reduced in vivo response to PPD at age 2 months, the prevalence ratio (PR) of having a PPD reaction being 0.75 (0.58-0.98), p = 0.033, and with a tendency for reduced likelihood of having a BCG scar (0.95 (0.91-1.00), p = 0.057)). Among children with a scar, OPV was associated with reduced scar size, the regression coefficient being -0.24 (-0.43-0.05), p = 0.012. Conclusions: This study is the first to address the consequences for the immune response to BCG of simultaneous administration with OPV. Worryingly, the results indicate that the common practice in low-income countries of administering OPV together with BCG at birth may down-regulate the response to BCG vaccine.