关键词： Poliovirus   Receptors   Capsid   Cellular receptors   HeLa cells   Cell surface receptors   Amino acids   Cell membranes   Viral RNA  

摘要： The interaction of poliovirus with its cell receptor initiates conformational changes that lead to uncoating of the viral RNA. Three types of genetic analyses have been used to study the poliovirus-receptor interaction: (i) mutagenesis of the poliovirus receptor (PVR), (ii) selection of viral mutants resistant to neutralization with soluble PVR, and (iii) selection of viral variants adapted to use mutant PVRs. The results of these studies show that a small portion of the first immunoglobulin-like domain of PVR contacts viral residues within a deep depression on the surface of the capsid that encircles the fivefold axis of symmetry. Viral capsid residues that influence the interaction with PVR are also found in locations such as the capsid interior that cannot directly contact PVR. These mutations might influence the ability of the capsid to undergo receptor-mediated conformational transitions that are necessary for high-affinity interactions with PVR.

关键词： 脊髓灰质炎病毒   抗体   制备  

摘要： 本文报通抗脊髓灰质类ＩｇＹ抗体的制备与纯化法，结果显示三型脊髓灰质炎病毒均于免疫鸡卵中产生特异抗体，并具有仅母体传递到卵黄的特性，抗体滴定度高达１：１６万，为生物学研究由鸡卵中制备ＩｇＹ抗体是有利的方法。

关键词： 脊髓灰质炎病毒   疫苗病毒株   监测  

摘要： 于１９９４年～１９９５年间，我们采用滑石粉──硅藻土夹心层法监测了昆明市盘龙江、大观河水中的肠道病毒，经脊灰病毒定型以及Ｔ特征试验和抗脊灰病毒单克隆抗体中和分析，鉴定为脊灰Ⅲ型和Ⅰ型疫苗病毒。本文结果可供我国消灭脊灰作参考。

关键词： poliovirus   translation   poly(rC) binding protein 2   protein sequence analysis  

摘要： The 5' noncoding region of poliovirus RNA contains an internal ribosome entry site (IRES) for cap-independent initiation of translation, Utilization of the IRES requires the participation of one or more cellular proteins that mediate events in the translation initiation reaction, but whose biochemical roles have not been defined, In this report, we identify a cellular RNA binding protein isolated from the ribosomal salt wash of uninfected HeLa cells that specifically binds to stem-loop IV, a domain located in the central part of the poliovirus IRES, The protein was isolated by specific RNA affinity chromatography, and 55% of its sequence was determined by automated liquid chromatography-tandem mass spectrometry. The sequence obtained matched that of poly(rC) binding protein 2 (PCBP2), previously identified as an RNA binding protein from human cells, PCBP2, as well as a related protein, PCBP1, was over-expressed in Escherichia coli after cloning the cDNAs into an expression plasmid to produce a histidine-tagged fusion protein, Specific interaction between recombinant PCBP2 and poliovirus stem-loop IV was demonstrated by RNA mobility shift analysis, The closely related PCBP1 showed no stable interaction with the RNA, Stem-loop IV RNA containing a three nucleotide insertion that abrogates translation activity and virus viability was unable to bind PCBP2.

关键词： Protein Processing   Post-Translational   Binding Sites   Hela Cells   Humans   Mutagenesis   Site-Directed   Mutation   Polioviruses   Protein Precursors   Proteins   RNA   Viral   Research Support   Non-U.S. Gov't   Viral Proteins  

摘要： The poliovirus genome comprises a single open reading frame which is translated to give one large polyprotein. The proteolytic cascade involved in the processing of this polyprotein is not yet understood in full detail, particularly concerning the processing of P2-P3, the precursor to the viral nonstructural polypeptides, 2A, 2B, 2C, 3A, 3B, 3C, and 3D. To investigate the possibility that the cleavage events within P2 and at the 2C/3A junction occur in an ordered fashion, we used oligonucleotide-directed mutagenesis of poliovirus cDNA to modify the 3C(pro)-mediated cleavage sites. The Gin residue of the Gln-Gly sequence at the 2A/2B, 2B/2C, and 2C/3A junctions in the poliovirus polyprotein was replaced by Asn, Glu, Asp, or Lys. The effects of each of these substitutions were studied in vivo after transfection onto HeLa cells and in vitro in a cell-free translation assay, using full-length mutated RNA transcripts. Only the mutant with the Glu-Gly sequence at the 2C/3A junction was viable. Analysis of the in vitro processing profiles showed that the efficiency of the 3C protease cleavage at any of the sites in P2 was in the following order: Gln-Gly >Glu-Gly >Asn-Gly. No cleavage could be detected with the Asp-Gly or Lys-Gly sequence at any junction. Lack of 2A/2B or 2B/2C cleavage had no consequences on the cleavage efficiency at other Gln-Gly sites in the polyprotein. Abolition of cleavage at the 2C/3A junction did not prevent the generation of the 2A, 2B, and 3CD polypeptides. Thus, these polypeptides could be produced independently of the generation of the P2 and P3 precursors. (C) 1996 Academic Press. Inc.

关键词： RNA tertiary structure   viral RNA replication  

摘要： The key steps in the replication of the poliovirus genome, initiation of (-) and (+) strands, require two different cis-acting elements, oriR and oriL, respectively, It has been proposed that the spatial organization of these elements is maintained by tertiary ('kissing') interactions between the loops of two constituent hairpins, Here, the putative partners of the kissing interaction within the oriR of the full-length poliovirus RNA were modified by site-directed mutagenesis, The destabilization of this interaction resulted in a severe suppression of the viral RNA synthesis, but the mutant transcripts proved to be infectious, With a single exception, the potential for the kissing interaction within the oriR of the recovered viruses was partially or completely restored due to either true reversions or second-site compensatory mutations, There was a good correlation between the restoration of this potential and the phenotypic properties of the viruses, It was concluded that the kissing interaction in the poliovirus oriR is functionally important, Using the above experimental data, a three-dimensional structure was derived by molecular modeling techniques? which demonstrated the overall feasibility of the proposed interactions and displayed the poliovirus oriR as a quasi-globular multi-domain structure.

关键词： 脊髓灰质炎疫苗   卡介苗   种牛痘   展成   人类需要   疾病   情景   生命   斗争   无数  

摘要： 提起疫苗,大家都不陌生。许多人会记起小时候种牛痘、划卡介苗的情景。的确,疫苗曾挽回了无数人的生命,在人类与疾病的斗争中起着不可低估的作用。那么,今天的疫苗已发展成什么样子了呢?

关键词： Poliovirus Vaccine   Inactivated   Child   Child   Preschool   Comparative Study   Cost-Benefit Analysis   Health Care Costs   Humans   Immunization Schedule   Infant   Models   Econometric   Multivariate Analysis   Policy Making   Poliomyelitis   Poliovirus Vaccine   Oral   Sensitivity and Specificity   United States   Vaccination  

摘要： Objective.-To evaluate the economic consequences of introducing inactivated poliovirus vaccine (IPV) into the routine vaccination schedule in the United States to reduce vaccine-associated paralytic poliomyelitis (VAPP). Design.-Cost-benefit and cost-effectiveness models were formulated to compare the current national 4-dose live attenuated oral poliovirus vaccine (OPV) schedule with a 4-dose IPV schedule or a sequential schedule of 2 doses of IPV followed by 2 doses of OPV. Model assumptions were derived from the National Health Interview Survey (1994), current prices for OPV and IPV, a Delphi panel, compensatory awards by the National Vaccine Injury Compensation Program, and published and unpublished reports. Main Outcome Measures.-Annual societal incremental cost relative to the current schedule for the cost-benefit model;cost per VAPP case prevented for the cost-effectiveness model. Results.-Changing to an IPV-only or a sequential schedule would cost $28.1 million and $14.7 million, respectively. The costs per case of VAPP prevented were estimated as $3.0 million and $3.1 million for each option, respectively. Outcomes were most sensitive to the number of additional visits that may occur to avoid multiple injections. Conclusions. The introduction of IPV into the routine vaccination schedule would not be cost-beneficial at current vaccine prices and with the current compensation awards paid to VAPP cases. The analysis provides a range of costs that policymakers need to consider if they wish to prevent VAPP. Although these costs are higher than those of other public health prevention programs, they may be justified because VAPP continues to occur as a result of government-mandated vaccination policies in the absence of known wild poliovirus transmission in the United States.

关键词： Cell Membrane Permeability   Biological Transport   Carrier Proteins   Choline   Hela Cells   Hygromycin B   Polioviruses   Recombinant Proteins   Research Support   Non-U.S. Gov't   Transfection   Uridine   Vaccinia virus   Viral Nonstructural Proteins  

摘要： Poliovirus infection leads to drastic alterations in membrane permeability late during infection. Transient expression of each nonstructural protein of poliovirus by means of recombinant vaccinia virus encoding the T7 RNA polymerase indicates that proteins 2B and 2BC strongly enhance membrane permeability to hygromycin B in HeLa cells, Almost no effect on expression of proteins 2C, 3A, 3AB, and 3C was found. Deletions and point mutations in 2B and 2BC have identified sequences in 2B involved in membrane permeabilization. Regions located at both ends of 2B are necessary to bring about these permeability alterations. A deletion of 11 amino acids of 2BC at the junction between 2B and 2C, as well as long deletions in 2C encompassing the GTPase motifs of this protein, do not impair the capacity of 2BC to modify the permeability of the membrane. The release of compounds such as choline or uridine from preloaded cells is also augmented by 2B and 2BC expression.

关键词： 强化免疫活动   脊灰   脊髓灰质炎疫苗   效果分析   局部爆发   常规免疫   发病率   中国   并存   湛江市  

摘要： 湛江市脊髓灰质炎疫苗强化免疫效果分析陈治玲，成树人湛江市１９８０脊髓灰质炎（下称脊灰）发病率为６．１９／十万，１９８０～１９９３年间每年均有脊灰流行并有间隙性局部爆发。１９８９年１２月至１９９３年３月我市在常规免疫的基础上进行了七轮应急服苗或强化免疫...