Comparative Genomic Analysis of Enterovirus 71 Revealed Six New Potential Neurovirulence-associated Sites

In the present study,the complete genomes of four common（4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014）and two virulent（11/EV71/Wenzhou/CHN/2014and 109/EV71/Wenzhou/CHN/2014）enterovirus 71（EV71）isolates were sequenced and described.They are 7405 bp in length and belong to EV71 sub-genotype C4 （C4a cluster）.

Clinical characteristics and treatment of severe encephalitis associated with neurogenic pulmonary edema caused by enterovirus 71 in China

BACKGROUND： Hand-foot-mouth disease has become a major public health issue in children in China. In the present prospective study we investigated the clinical characteristics and emergency management of children with severe encephalitis associated with NPE caused by enterovirus 71.METHODS： The study was conducted in 2 pediatric intensive care units （PICUs） over a 2-month period. Clinical records were reviewed of critically ill children with severe encephalitis associated with NPE caused by EV71 who were admitted to PICUs during the period of May to June 2008 in Fuyang.RESULTS： We reviewed the complete records of 36 children, of whom 23 （63.9%） were male and 13 （36.1%） female. Their age ranged from 4 to 48 months, with an average of 15.8 months. All children except one were under 3 years of age. The overall mortality in these children was 19.4%. The average duration of critical life threatening signs and symptoms was 2.1 days （12 hours-5 days）. Nervous system diseases included brainstem encephalitis in 27 children （75%）, brainstem encephalitis associated with myelitis in 6 children （16.7%）, and general encephalitis in 3 chidren （8.3%）, respectively. In 12 patients of NPE （33.3%） pink or bloody bubble sputum and asymmetric pulmonary edema or hemorrhage was the primary manifestation but no typical exanthema was observed. Five children died of acute onset of NPE and / or pulmonary hemorrhage with rapid progression of cardiopulmonary failure within hours after admission. Therapeutic management consisted of mechanical ventilation and administration of mannitol, methylprednisolone, intravenous immunoglobulin （IVIG） and vasoactive drugs, associated with the need of fluid volume resuscitation in 9 （25%） of the 36 children.CONCLUSION： In children less than 3 years of age found to be affected by severe EV71 encephalitis associated with NPE, one fifth may die. The major organ systems infected by severe EV71 include the central nervous system, the respiratory system, and the cardiovascular system. Early diagnosis and evaluation, respiratory support, treatment of intracranial hypertension, and mainttenance of function of the cardiovascular system are the most important therapeutic measures.

EV71感染手足口病患儿外周血检测Treg细胞、TH17细胞、TGF-β、IL-17A的临床意义

目的研究EV71感染手足口病患儿外周血CD4+CD2+5Foxp3high调节性T细胞(Treg细胞)、TH17细胞及细胞因子TGF-β、IL-17A,分析其在EV71感染手足口病患儿发病机制中的作用及临床意义。方法收集EV71感染手足口病患儿及健康对照组外周抗凝静脉血,流式细胞仪检测CD4+CD2+5 Foxp3highTreg细胞、TH17细胞的表达,ELISA法检测研究对象血清中TGF-β、IL-17A的水平。结果显示EV71感染手足口病患儿CD4+CD2+5 Foxp3high Treg细胞百分率和血清中TGF-β水平明显低于健康对照组(P<0.05),TH17细胞百分率和血清中IL-17A水平明显高于健康对照组(P<0.05)。结论 EV71感染手足口病患儿体内存在细胞免疫功能紊乱,病毒感染可能是引起机体免疫功能异常的关键。

Genetic Analysis of the VP1 Region of Human Enterovirus 71 Strains Isolated in Fuyang,China,During 2008

Enterovirus 71 （EV71） is a common cause of Hand, foot, and mouth disease （HFMD） and may also cause severe neurological diseases, such as encephalitis and poliomyelitis-like paralysis. To examine the genetic diversity of EV71, we determined and analyzed the complete VP1 sequences （891 nueleotides） from nine EV71 strains isolated in Fuyang, China. We found that nine EV71 strains isolated were over 98% homologous at the nucleotide level and 93%-100% homologous tO members of the C4 subgenogroup. At the amino acid level, these Fuyang strains were 99% -100% homologous to one another, 97%-100% homologous to members of the C4 subgenogroup, and the histidine（H） at amino acid position 22 was conserved among the Fuyang strains. The results indicate that Fuyang isolates belong to genotype C4, and an H at position 22 appears to be a marker for the Fuyang strains.

Antiviral Activity of GuiQi Polysaccharides against Enterovirus 71 in vitro

In this study,we have investigated the antiviral activity of GuiQi polysaccharides (GQP) upon enterovirus 71 (EV71) in vitro.An assay using methyl thiazolyl tetrazolium (MTT),and analyses of cytopathic effects (CPE)were used to examine the antiviral activity of GQP upon Vero cells infected with EV71.The results revealed that GQP at concentrations below 31.2μg/mL exhibited significant antiviral effects upon EV71 when applied under three different experimental protocols.GQP was most strongly active in preventing the adsorption of EV71 to target cells and in this respect it was significantly more effective than ribavirin.In addition,it was clear that GQP could inhibit viral replication when added to cells 2 h after infection,but if added at the point of infection its effect was weak.GQP is considered to be less toxic than ribavirin,and may warrant further evaluation as a possible agent in the treatment of hand,foot and mouth disease (HFMD).

Safe and Objective Assay of Enterovirus 71 Neutralizing Antibodies via Pseudovirus

Current serum neutralization assays based on the inhibition of the cytopathic effect（Nt-CPE） need to ma nipulate live viruses, which are time-consuming, labor-intensive, and have the potential exposure to infectious agents, so a safe and objective assay via pseudovirus for the fast and efficient detection of enterovirus 71（EV71） neutralizing antibodies was developed. First, we generated EV71 pseudovirus containing firefly luciferase gene in place of the capsid gene P1 in EV71 genome. Vero cells infected with 200 CCID50（50% cell culture infective dose） of EV71 pseudovirus for 24 h were found to have the best performance. Seval sera were measured by EV71 pseudoparticle neutralization assay（Nt-PPN） and the conventional serological method Nt-CPE. Neutralizing antibody titers measured by Nt-PPN and those obtained by Nt-CPE demonstrate a high correlation between the two methods. Overall, the PPN assay represents a valid alternative to conventional serological methods for the evaluation of EV71 neutralizing anti bodies. This method can be used for detecting neutralizing antibodies of other picornaviruses, such as hepatitis A vi rus（HAV） and coxsackievirus 16（CVA16）, and make it possible to determine whether there is cross-reactivity be tween EV71 and CVA16.

Contribution of 3CD Region to the Virulence of Enterovirus 71

Enterovirus 71 （EV71） and Coxsackievirus A16 （CoxA16） are the major pathogens causing hand, foot, and mouth disease （HFMD） that occurs primarily in children and infants with mild clinical manifestations. HFMD caused by EV71 could develop to a fatal neurological complication.

检测EV71和EV-U的TaqMan-LNA探针多重荧光RT-PCR的建立

目的建立一种针对手足口病病原体的快速准确检测方法。方法利用TaqMan-LNA探针建立多重荧光定量RT-PCR方法,同时检测肠道病毒71型(EV71)和肠道病毒通用型(EV-U),用含有目的序列RNA的标准品制备标准曲线,对病毒进行准确定量,同时对该方法的特异性、灵敏度、重复性进行评估。结果用TaqMan-LNA探针多重荧光RT-PCR法检测CoxA16、CoxB2、EV71病毒和其他人类病毒RNA,证实其特异性为100%;对EV71和EV-U的检测灵敏度均达到102拷贝/μl;将EV71和EV-U的RNA标准品进行重复性实验,其批内、批间变异系数分别为0.97%～2.02%和0.89%～2.13%。结论本方法灵敏度较高,特异性强,重复性好,适用于手足口病的临床检测。

红景天苷体外抗EV71病毒的作用

应用MTT法研究红景天苷对Vero细胞的毒性以及对肠道病毒71型(Enterovirus 71,EV71)的抑制作用,通过吸附试验和穿入试验观察红景天苷是否对EV71的吸附和穿入具有抑制作用。结果表明,红景天苷的细胞毒性低,半数细胞毒性浓度(CC50)为4.25 mg/mL。药物在病毒感染前加入(药物预处理)、药物和病毒同时加入及药物在病毒感染后加入都能够抑制病毒,以药物预处理细胞抗病毒作用最好;红景天苷能够抑制病毒的吸附和穿入作用,对吸附作用抑制效果更强。表明红景天苷能够在体外抑制病毒对细胞的感染。

Rational design of a DNA-launched live attenuated vaccine against human enterovirus 71

Human Enterovirus 71(EV71)has emerged as one of the predominant causative agents of hand,foot and mouth disease(HFMD)with global impact.Despite the inactivated vaccine being licensed,other vaccine candidates based on advanced technology platforms are under development.In this report,we rationally designed and constructed two DNA-launched live attenuated vaccine candidates(pDL-EV71)under the control of specific promoters.In vitro and in vivo transfection with pDL-EV71 driven by the CMV promoter successfully yielded fully infectious EV71.More importantly,the administration of pDL-EV71 did not cause clinical symptoms following intracranial or intramuscular inoculation in neonatal and IFNα/βR/mice,demonstrating its safety profile.Moreover,a single-dose or two-dose immunization with pDL-EV71 elicited robust neutralizing antibodies against EV71 as well as an antigen-specific cellular response in mice.A single-dose immunization with 10μg of pDL-EV71 conferred complete protection against lethal EV71 infection in neonates born to immunized maternal mice.Overall,our present results demonstrate that pDL-EV71 is a safe and effective vaccine candidate against EV71 for further development.

A Comparison of the Biological Characteristics of EV71 C4 Subtypes from Different Epidemic Strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates suggested that they were highly co-related with genetic identity similar to other previously reported EV71 strains in China. Additionally, these strains were identified to display some obvious proliferation dynamics and plaque morphology when propagated in Vero cells. However, a distinctive difference in pathogenic ability in neonatal mice was found. Some differences in cross neutralization test & immunogenic analysis were also found. All these results are related to the biological characterization of circulating EV71 strains in China and aid in the development of an EV71 vaccine in the future.

人源抗EV71病毒中和表位SP70的Fab抗体研制

目的构建人源抗EV71病毒Fab噬菌体抗体库,筛选具有中和活性的人源单克隆抗体,为EV71感染引起的手足口病临床诊断及治疗奠定基础。方法从成人志愿者抗凝血中分离外周淋巴细胞,提取总RNA并逆转录为cDNA。以cDNA为模板,用人源IgG Fab段基因引物扩增轻链及重链Fd区基因,分步克隆至pComb3载体,构建Fab噬菌体抗体库。以SP70为抗原对Fab噬菌体抗体库进行富集筛选,将获得的重组噬菌体感染XL1-Blue菌并诱导表达,用SP70对诱导表达的菌上清进行筛选。结果共获得3株轻、重链基因组合序列不同的克隆,且这3株Fab抗体可特异性结合SP70多肽。结论成功构建人源抗EV71病毒Fab噬菌体抗体库,并从中筛选出3株针对EV71病毒结构蛋白VP1上中和线性表位SP70的特异性人源Fab抗体,为研发新的手足口病诊断和治疗工具奠定基础。

肠道病毒71型感染手足口病患儿Th17/Treg比例失衡与病情程度的关系

目的 分析辅助性T细胞17(Th17)/调节性T细胞(Treg)比例失衡与肠道病毒71型(EV71)感染手足口病患儿病情程度的关系及临床意义。方法 将2019年8月—2021年12月上海健康医学院附属嘉定区中心医院收治的EV71感染手足口病患儿150例纳入研究,EV71感染手足口病患儿根据病情严重程度分为普通型组125例,重型组25例,另择同期90例体检健康儿童作为对照组,回顾性收集研究对象的临床资料。比较3组全血Th17、Treg、Th17/Treg水平,血清Th17、Treg相关细胞因子水平,通过Pearson相关分析法分析全血Th17、Treg、Th17/Treg与疾病严重程度的相关性。结果 重型组、普通型组、对照组全血Th17、Th17/Treg水平呈下降趋势,全血Treg水平呈升高趋势,组间比较差异有统计学意义(P<0.05)。重型组、普通型组、对照组白细胞介素-17(IL-17)、IL-6水平呈下降趋势,血清IL-23、IL-10、转化生长因子-β(TGF-β)水平呈升高趋势,组间比较差异有统计学意义(P<0.05)。Pearson相关分析法结果显示,疾病严重程度与全血Treg水平呈负相关(r=-0.430,P<0.05),疾病严重程度与全血Th17、Th17/Treg水平呈正相关(r=0.713、0.352,P<0.05)。结论 EV71感染手足口病患儿感染后全血Th17水平提高,全血Treg降低,Th17/Treg比例失衡,可加重机体炎症反应,与病情严重程度密切相关。

2010-2017年天津市滨海新区健康人群人肠道病毒71型血清中和抗体动态变化研究

目的:了解天津市滨海新区健康人群人肠道病毒71型(EV-A71)中和抗体动态变化,为手足口病防控方案提供依据。方法:采集2010-2017年天津市滨海新区健康人的血清学标本368份,进行EV-A71中和抗体测定,并对监测结果进行统计学分析。结果:EV-A71中和抗体阳性率为79.35%;不同年份间的抗体阳性率差异有统计学意义(χ^2=6.695,P=0.01),呈周期性变化;不同年龄组人群的抗体阳性率差异有统计学意义(χ^2=46.531,P<0.01),5岁及以下年龄组抗体阳性率最低为59.26%;5岁以下各年龄组抗体阳性率无统计学差异(χ^2=1.481,P=0.830);不同性别间抗体阳性率差异无统计学意义(χ^2=3.480,P=0.062);以健康人群EV-A71中和抗体阳性率作为应变量,对健康人群的卫生习惯及环境进行Logistic回归分析,发现与没去过医院的相比,半年内去过医院患病风险更大(OR=2.291,95%CI:1.488~4.946)。结论:天津市滨海新区人群EV-A71中和抗体水平较高,易感人群为5岁及以下年龄组儿童,继续加强和完善EV-A71流行监测系统是防控手足口病的重要环节。

肠道病毒71型疫苗质量控制研究进展

手足口病(Hand foot and mouth disease,HFMD)已成为西太平洋区严重的公共卫生问题之一,肠道病毒71型(Enterovirus 71,EV71)是引起HFMD的主要病原体,研发疫苗是控制HFMD流行的有效手段。目前世界范围已有5个EV71全病毒灭活疫苗进入临床试验,其中中国研制的3种EV71疫苗已分别完成III期临床试验,结果表明3种疫苗都具有良好的安全性和保护效果。在EV71疫苗研发中,抗原质控的方法和标准是研发的瓶颈,其中抗原活性测定是工序工艺优化、免疫原性评价和剂量确定的关键指标。综述了EV71疫苗抗原质控的研究进展。

AIMP2 restricts EV71 replication by recruiting SMURF2 to promote the degradation of 3D polymerase

Hand,foot and mouth disease(HFMD),mainly caused by enterovirus 71(EV71),has frequently occurred in the Asia-Pacific region,posing a significant threat to the health of infants and young children.Therefore,research on the infection mechanism and pathogenicity of enteroviruses is increasingly becoming important.The 3D polymerase,as the most critical RNA-dependent RNA polymerase(RdRp)for EV71 replication,is widely targeted to inhibit EV71 infection.In this study,we identified a novel host protein,AIMP2,capable of binding to 3D polymerase and inhibiting EV71 infection.Subsequent investigations revealed that AIMP2 recruits the E3 ligase SMURF2,which mediates the polyubiquitination and degradation of 3D polymerase.Furthermore,the antiviral effect of AIMP2 extended to the CVA16 and CVB1 serotypes.Our research has uncovered the dynamic regulatory function of AIMP2 during EV71 infection,revealing a novel antiviral mechanism and providing new insights for the development of antienteroviral therapeutic strategies.

PLX8394,a RAF inhibitor,inhibits enterovirus 71 replication by blocking RAF/MEK/ERK signaling

Enterovirus 71(EV71)poses a serious threat to human health,with scattered outbreaks worldwide.There are several vaccines against a few EV71 strains but no efficient drug for the treatment of EV71 infection.Therefore,it is urgent and of significance to develop anti-EV71 drugs.Here,we found that PLX8394,a RAF inhibitor,possesses high antiviral activity against EV71 in vitro,being superior to the traditional clinical drug ribavirin.Moreover,PLX8394 exhibits broad-spectrum antiviral activity against enteroviruses.Notably,in a suckling mouse model,PLX8394 provided a 70%protection rate for EV71-infected mice,reduced the viral load in liver and heart tissues,and relieved the inflammatory response.A mechanistic study showed that PLX8394 inhibited EV71 by suppressing the RAF/MEK/ERK signaling pathway.Thus,PLX8394 lays a foundation for the development of new drugs against EV71.

肠道病毒A组71型在人脐静脉血管内皮细胞中的增殖及对细胞骨架的影响

目的研究肠道病毒A组71型(Enterovirus group A type 71,EV-A71)在人脐静脉血管内皮细胞(Human umbilical vein endothelial cells,HUVECs)中的增殖及对细胞骨架造成的影响,初步探讨其与病毒血症发生的关系。方法采用qRT-PCR技术及免疫荧光技术检测EV-A71在HUVECs中的复制和增殖,用免疫荧光双染色技术观察三种细胞骨架在EV-A71感染后的变化。结果 EV-A71能够有效感染HUVECs,且感染后24 h在细胞内复制达到高峰。病毒感染后微丝骨架完全解聚,微管骨架排列方式发生改变,而中间纤维结构模糊不清;同时检测到微管及中间纤维与病毒抗原共存。结论 EV-A71可以感染HUVECs并在其内有效复制增殖,同时诱导HUVECs三种细胞骨架发生改变,提示细胞骨架可能参与EV-A71感染HUVECs的过程。

Ubiquitin-specific protease 24 promotes EV71 infection by restricting K63-linked polyubiquitination of TBK1

TANK-binding kinase 1(TBK1)is an essential protein kinase for activation of interferon regulatory factor 3(IRF3)and induction of the type I interferons(IFN-I).Although the biochemical regulation of TBK1 activation has been studied,little is known about how enterovirus 71(EV71)employs the deubiquitinases(DUBs)to regulate TBK1 activation for viral immune evasion.Here,we found that EV71 infection upregulated the expression of ubiquitinspecific protease 24(USP24).Further studies revealed that USP24 physically interacted with TBK1,and can reduce K63-linked polyubiquitination of TBK1.Knockdown of USP24 upregulated TBK1 K63-linked polyubiquitination,promoted the phosphorylation and nuclear translocation of IRF3,and in turn improved IFN-I production during EV71 infection.As a consequence,USP24 knockdown dramatically inhibited EV71 infection.This study revealed USP24 as a novel regulator of TBK1 activation,which promotes the understanding of immune evasion mechanisms of EV71 and could provide a potential strategy for treatment of EV71 infection.

The impact of EV71 vaccination program on hand,foot and mouth disease in Zhejiang Province,China:A negative control study

Objective:To estimate the potential causal impact of Enterovirus A71(EV71)vaccination program on the reduction of EV71-infected hand,foot,and mouth disease(HFMD)in Zhejiang Province.Methods:We utilized the longitudinal surveillance dataset of HFMD and EV71 vaccination in Zhejiang Province during 2010-2019.We estimated vaccine efficacy using a Bayesian structured time series(BSTS)model,and employed a negative control outcome(NCO)model to detect unmeasured confounding and reveal potential causal association.Results:We estimated that 20,132 EV71 cases(95%CI:16,733,23,532)were prevented by vaccination program during 2017-2019,corresponding to a reduction of 29%(95%CI:24%,34%).The effectiveness of vaccination increased annually,with reductions of 11%(95%CI:6%,16%)in 2017 and 66%(95%CI:61%,71%)in 2019.Children under 5 years old obtained greater benefits compared to those over 5 years.Cities with higher vaccination coverage experienced a sharper EV71 reduction compared to those with lower coverage.The NCO model detected no confounding factors in the association between vaccination and EV71 cases reduction.