关键词： POLIOVIRUS   POLIO patients   CHILDREN   VIRAL vaccines   VIRAL genomes  

摘要： Background. Five cases of poliomyelitis due to type 2 or 3 recombinant vaccine-derived polioviruses (VDPVs) were reported in the Toliara province of Madagascar in 2005. Methods. We sequenced the genome of the VDPVs isolated from the patients and from 12 healthy children and characterized phenotypic aspects, including pathogenicity, in mice transgenic for the poliovirus receptor. Results. We identified 6 highly complex mosaic recombinant lineages composed of sequences derived from different vaccine polioviruses and other species C human enteroviruses (HEV-Cs). Most had some recombinant genome features in common and contained nucleotide sequences closely related to certain cocirculating coxsackie A virus isolates. However, they differed in terms of their recombinant characteristics or nucleotide substitutions and phenotypic features. All VDPVs were neurovirulent in mice. Conclusions. This study confirms the genetic relationship between type 2 and 3 VDPVs, indicating that both types can be involved in a single outbreak of disease. Our results highlight the various ways in which a vaccine-derived poliovirus may become pathogenic in complex viral ecosystems, through frequent recombination events and mutations. Intertypic recombination between cocirculating HEV-Cs (including polioviruses) appears to be a common mechanism of genetic plasticity underlying transverse genetic variability.

关键词： POLIOVIRUS   POLYPEPTIDES   PROTEIN structure   VIRAL antibodies   PROTEIN binding   ELECTRON microscopy   PROTEIN folding  

摘要： At 37 degrees C, the structure of poliovirus is dynamic, and internal polypeptides VP4 and N terminus of VP1 (residues 1 to 53) externalize reversibly. An Fab fragment of a monospecific antibody, which binds to residues 39 to 55 of VP1, was utilized to locate the N termini of VP1 in native (160S) particles in this "breathing" state. Fab and virus were mixed and imaged via cryogenic electron microscopy. The resulting reconstruction showed the capsid expands similarly to the irreversibly altered cell entry intermediate (135S) particle, but the N terminus of VP1 is located near the 2-fold axes, instead of the "propeller tip" as in 135S particles.

关键词： VIRAL proteins   PEPTIDES   VIRAL replication   POLIOVIRUS   MEMBRANE proteins   ENTEROVIRUS diseases   SMALL interfering RNA  

摘要： Poliovirus (PV) modifies membrane-trafficking machinery in host cells for its viral RNA replication. To date, ARF1, ACBD3, BIG1/BIG2, GBF1, RTN3, and PI4KB have been identified as host factors of enterovirus (EV), including PV, involved in membrane traffic. In this study, we performed small interfering RNA (siRNA) screening targeting membrane-trafficking genes for host factors required for PV replication. We identified valosin-containing protein (VCP/p97) as a host factor of PV replication required after viral protein synthesis, and its ATPase activity was essential for PV replication. VCP colocalized with viral proteins 2BC/2C and 3AB/3B in PV-infected cells and showed an interaction with 2BC and 3AB but not with 2C and 3A. Knockdown of VCP did not suppress the replication of coxsackievirus B3 or Aichi virus. A VCP-knockdown-resistant PV mutant had an A4881G (a mutation of E253G in 2C) mutation, which is known as a determinant of a secretion inhibition-negative phenotype. However, knockdown of VCP did not affect the inhibition of cellular protein secretion caused by overexpression of each individual viral protein. These results suggested that VCP is a host factor required for viral RNA replication of PV among membrane-trafficking proteins and provides a novel link between cellular protein secretion and viral RNA replication.

关键词： Rotavirus   Vaccines   Diarrhea   Oral polio vaccine   Immunogenicity   Co-administration  

摘要： In recent years, two live, oral rotavirus vaccines have been successfully tested in developing and industrialized countries, and both vaccines are now recommended by the World Health Organization for all children worldwide. Both immunogenicity and efficacy of these rotavirus vaccines has been lower in developing compared to industrialized settings. We reviewed the data on the effect of trivalent OPV on the immunogenicity and efficacy of two rotavirus vaccines currently recommended by the WHO. While rotavirus vaccines have not affected immune responses to OPV, in general, the immune responses (i.e., antibody levels) to rotavirus vaccination were lower when rotavirus vaccines were co-administered with OPV. Limited data suggests that the interference is greater after the first dose of OPV, presumably because the first dose is associated with greatest intestinal replication of vaccine polio virus strains, and this interference is largely overcome with subsequent rotavirus vaccine doses. Despite the lower immunogenicity, one large efficacy study in middle income Latin American countries showed no decrease in protective efficacy of rotavirus vaccine in infants receiving concurrent OPV. While these data are encouraging and support simultaneous administration of rotavirus vaccines and OPV, additional evidence should be gathered as rotavirus vaccines are used more widely in developing country settings, where OPV is routinely used, rather than inactivated polio vaccine. Published by Elsevier Ltd.

关键词： RNA-dependent RNA polymerase   poliovirus   template strand interactions   elongation complex stability   virus replication  

摘要： Positive-strand RNA viruses within the Picornaviridae family express an RNA-dependent RNA polymerase, 3D(Pol), that is required for viral RNA replication. Structures of 3D(Pol) from poliovirus, coxsackievirus, human rhinoviruses, and other picornaviruses reveal a putative template RNA entry channel on the surface of the enzyme fingers domain. Basic amino acids and tyrosine residues along this entry channel are predicted to form ionic and base stacking interactions with the viral RNA template as it enters the polymerase active site. We generated a series of alanine substitution mutations at these residues in the poliovirus polymerase and assayed their effects on template RNA binding, RNA synthesis initiation, rates of RNA elongation, elongation complex (EC) stability, and virus growth. The results show that basic residues K125, R128, and R188 are important for template RNA binding, while tyrosines Y118 and Y148 are required for efficient initiation of RNA synthesis and for EC stability. Alanine substitutions of tyrosines 118 and 148 at the tip of the 3D(Pol) pinky finger drastically decreased the rate of initiation as well as EC stability, but without affecting template RNA binding or RNA elongation rates. Viable poliovirus was recovered from HeLa cells transfected with mutant RNAs;however, mutations that dramatically inhibited template RNA binding (K125A-K126A and R188A), RNA synthesis initiation (Y118A, Y148A), or EC stability (Y118A, Y148A) were not stably maintained in progeny virus. These data identify key residues within the template RNA entry channel and begin to define their distinct mechanistic roles within RNA ECs. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： POLIOVIRUS   NECTINS   ADHERENS junctions   BIOLOGICAL response modifiers   CELL adhesion  

摘要： Nectins (nectin1-4) and Necls [nectin-like (Necl1-5)] are Ig superfamily cell adhesion molecules that regulate cell differentiation and tissue morphogenesis. Adherens junction formation and subsequent cell-cell signaling is initiated by the assembly of higher-order receptor clusters of cognate molecules on juxtaposed cells. However, the structural and mechanistic details of signaling cluster formation remain unclear. Here, we report the crystal structure of poliovirus receptor (PVR)/Nectin-like-5/CD155) in complex with its cognate immunoreceptor ligand T-cell-Ig-and-ITIM-domain (TIGIT). The TIGIT/PVR interface reveals a conserved specific "lock-and-key" interaction. Notably, two TIGIT/PVR dimers assemble into a heterotetramer with a core TIGIT/TIGIT cis-homodimer, each TIGIT molecule binding one PVR molecule. Structure-guided mutations that disrupt the TIGIT/TIGIT interface limit both TIGIT/PVR-mediated cell adhesion and TIGIT-induced PVR phosphorylation in primary dendritic cells. Our data suggest a cis-trans receptor clustering mechanism for cell adhesion and signaling by the TIGIT/PVR complex and provide structural insights into how the PVR family of immunoregulators function.

关键词： 脊髓灰质炎疫苗(OPV)   强化免疫   效果分析   轮台,新疆  

摘要： 目的分析评价2011年新疆轮台县口服脊髓灰质炎疫苗(OPV)强化免疫活动的实施效果。方法对全县各乡镇、街道、村、居委会、机关单位上报的口服OPV应急强化免疫的资料进行汇总分析。结果 2011年轮台县在全县范围内开展了5轮OPV强化免疫活动,每轮报告合计应种人数323 931人,实种人数322 673人;强化免疫前"零"剂次儿童数共为1 000人,每个年龄组每轮报告服苗率均>98%,小于1岁接种人数为959人,为继续保持全县无脊髓灰质炎状态打下了基础。结论通过OPV强化免疫活动,提高了全县易感人群的免疫水平,为建立南疆坚实的免疫屏障,发挥了积极的作用。

关键词： 疫苗   脊髓灰质炎   病毒   调查  

摘要： 目的分析疫苗衍生脊髓灰质炎病毒患者发病原因,并探索控制对策。方法对发生VDPV的患者进行个案调查,采集大便标本分离病毒;开展急性弛缓性麻痹患者主动搜索;对患者所在地及相邻地区开展口服脊髓灰质炎减毒活疫苗快速评价;对密切接触者和周围健康儿童进行大便标本带毒情况调查;开展应急免疫。结果该病发病症状属于AFP,并从其标本中分离1型VDPV病毒和2型疫苗病毒,最终分类诊断为VDPV;患者密切接触者及周围健康儿童大便标本分离到脊髓灰质炎疫苗病毒,无VDPV;当地OPV3接种率偏低。结论该VDPV患者未在当地造成循环;今后务必引起高度重视,维持高水平的OPV3接种率,保持AFP监测系统的灵敏性,加强技术培训和督导检查。

关键词： 脊髓灰质炎后综合征   癌,小细胞   副肿瘤综合征,神经系统  

摘要： 报道1例以肢体无力为首发症状的病人,误诊为脊髓灰质炎后综合征(PPS),后经病理检查确诊为小细胞肺癌并副癌综合征。结合文献对神经系统副癌综合征和PPS进行分析比较,以提高对该病的认识。

关键词： Ⅱ型脊髓灰质炎病毒   VP1编码区   基因特征  

摘要： 为维持中国无脊髓灰质炎(脊灰)状态及疫苗免疫策略的转变提供科学依据,本文对中国(不包括港澳台地区,以下同)2010年从急性弛缓性麻痹(Acute flaccid paralysis,AFP)病例监测系统分离的123株非野毒Ⅱ型脊灰病毒(Po-liovirus,PV)进行基因特征分析。利用逆转录-聚合酶链反应(Reverse transcription-polymerase chain reaction,RT-PCR)扩增VP1编码区,并对扩增产物进行序列测定,测序结果经Sequencher 4.8、BioEdit 7.0.9和MEGA 5.0软件分析。结果显示2010年未发现脊灰野病毒(Wild poliovirus,WPV)。65株PV在VP1编码区nt2 909发生突变,同时该位点又是已知的神经毒力决定位点。从云南省分离到2株疫苗衍生脊灰病毒(Vaccine-derived poliovirus,VDPVs),经流行病学和实验室检测结果分析表明,这2株都不同于以往发现的VDPVs,是新发现的VDPVs。建议加强全国AFP病例的流行病学和实验室监测和检测,为及时发现VDPVs传播和WPV的输入性暴发提供科学依据。