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Background Rhinoviruses from the Enterovirus genus cause frequent infections and induce remarkably high titres of anticapsid antigen antibodies in asthmatics, while the prevalence of neutralising antibodies to the gut-trophic echoviruses from the same genus is diminished. Objective To assess the absolute and specific antibody titres to VP1 antigens of the gut-trophic enteroviruses, echovirus 30 and Sabin 1 poliovirus, in asthmatic and non-asthmatic children. Methods Recombinant polypeptides representing the VP1 capsid antigens of echovirus 30 and Sabin poliovirus 1 were produced. Their ability to bind IgG1 antibodies from the plasma of asthmatic ( n = 45) and non-asthmatic ( n = 29) children were quantitated by immunoassays that incorporated immunoabsorptions to remove cross-reactivity. Results The IgG1 antibody titres and prevalence of antibody binding to echovirus 30 were significantly lower for asthmatic children compared to controls ( P < 0.05) and inversely correlated with total IgE levels for the whole study population ( r = -0.262; P < 0.05). There was no difference in the prevalence and titre between groups to the VP1 antigen of Sabin poliovirus. Anti-tetanus toxoid titres measured for comparison did not correlate with anti-echovirus or poliovirus, but correlated with anti-rhinovirus titres in controls but not asthmatics, where the titres were higher for the asthmatic group. Conclusions and Clinical Relevance The associations of lower antibody titres of asthmatic children to echovirus reported here and those of our previous findings of a heightened response to rhinovirus suggest a dichotomy where respiratory enterovirus infection/immunity increases the probability of developing asthma and enteric infections lower the risk. This provides further support for the concept of intestinal infection playing a key role in the development of allergic respiratory disease. [ABSTRACT FROM AUTHOR]

Background: Eleven new human polyomaviruses (HPyVs) have been identified in the last decade. Serological studies show that these novel HPyVs sub-clinically infect humans at an early age. The routes of infection, entry pathways, and cell tropism of new HPyVs remain unknown. VP1 proteins of polyomaviruses can assembly into virus-like particles (VLPs). As cell culturing systems for HPyV are currently not available, VP1-derived VLPs may be useful tools in basic research and biotechnological applications. Results: Recombinant VP1-derived VLPs from 11 newly identified HPyVs were efficiently expressed in yeast. VP1 proteins derived from Merkel cell polyomavirus (MCPyV), trichodysplasia spinulosa-associated polyomavirus (TSPyV), and New Jersey polyomavirus (NJPyV) self-assembled into homogeneous similarly-sized VLPs. Karolinska Institutet polyomavirus (KIPyV), HPyV7, HPyV9, HPyV10, and St. Louis polyomavirus (STLPyV) VP1 proteins formed VLPs that varied in size with diameters ranging from 20 to 60 nm. Smaller-sized VLPs (25-35 nm in diameter) predominated in preparations from Washington University polyomavirus (WUPyV) and HPyV6. Attempts to express recombinant HPyV12 VP1-derived VLPs in yeast indicate that translation of VP1 might start at the second of two potential translation initiation sites in the VP1-encoding open reading frame (ORF). This translation resulted in a 364-amino acid-long VP1 protein, which efficiently self-assembled into typical PyV VLPs. MCPyV-, KIPyV-, TSPyV-, HPyV9-, HPyV10-, and HPyV12-derived VLPs showed hemagglutination (HA) assay activity in guinea pig erythrocytes, whereas WUPyV-, HPyV6-, HPyV7-, STLPyV- and NJPyV-derived VP1 VLPs did not. Conclusions: The yeast expression system was successfully utilized for high-throughput production of recombinant VP1-derived VLPs from 11 newly identified HPyVs. HPyV12 VP1-derived VLPs were generated from the second of two potential translation initiation sites in the VP1-encoding ORF. Recombinant VLPs produced in yeast originated from different HPyVs demonstrated distinct HA activities and may be useful in virus diagnostics, capsid structure studies, or investigation of entry pathways and cell tropism of HPyVs until cell culture systems for new HPyVs are developed. [ABSTRACT FROM AUTHOR]

Echovirus 3 (E3) serotype has been related with several neurologic diseases, although it constitutes one of the rarely isolated serotypes, with no report of epidemics in Europe. The aim of the present study was to provide insights into the molecular epidemiology and evolution of this enterovirus serotype, while an E3 strain was isolated from sewage in Greece, four years after the initial isolation of the only reported E3 strain in the same geographical region. Phylogenetic analysis of the complete VP1 genomic region of that E3 strain and of those available in GenBank suggested three main genogroups that were further subdivided into seven subgenogroups. Further evolutionary analysis suggested that VP1 genomic region of E3 was dominated by purifying selection, as the vast majority of genetic diversity presumably occurred through synonymous nucleotide substitutions and the substitution rate for complete and partial VP1 sequences was calculated to be 8.13 × 10 −3 and 7.72 × 10 −3 substitutions/site/year respectively. The partial VP1 sequence analysis revealed the composite epidemiology of this serotype, as the strains of the three genogroups presented different epidemiological characteristics. [ABSTRACT FROM AUTHOR]

Measles and rubella virus are usually considered as the causative agents in patients with febrile rash illness (FRI). However, investigators have identified that enteroviruses are also associated with FRI, and the present study was undertaken to investigate this association. In the study, 20 throat swab samples were collected from patients suffering from rash and fever between April and July in 2013. The 20 samples tested negative for measles virus, but all were positive when reverse transcription-polymerase chain reaction was performed using enterovirus universal primers. Specifically, five tested positive for Coxsackie B3 virus (CVB3). The titers of the five CVB3 isolates were 106.5, 106.4, 107.5, 106.5 and 106.5 tissue culture infectious dose50/100 µl respectively. The partial VP1 sequences of the five CVB3 isolates were identical to each other and were closely associated with the CVB3/MKP and CVB3/Macocy strains, which are known to induce myocarditis and neonatal diseases of the central nervous system. In conclusion, CVB3 may cause symptoms of fever and rash and should be differentiated from measles, rubella and other infectious pathogens. The five CVB3 isolates described in the study were genetically similar to each other and to other local CVB3 strains. The results provide further data on the viral pathogen spectrum associated with FRI. [ABSTRACT FROM AUTHOR]

Background Encephalomyocarditis virus (EMCV) can cause myocarditis, respiratory failure, reproductive failure, and sudden death in pre-weaned piglets, which has been isolated in China. EMCV VP1 protein was one of the most important structural proteins and played an important role in the protective immunity. In this study, 10 monoclonal antibodies (McAbs) against EMCV VP1 were screened and identified. Results Epitope mapping results indicated that McAbs (6E11, 7A7, 7C9) specifically recognized the linear epitopes V(2)ENAEK(7), McAbs (1D1, 2A2, 5A1, 5A11, 5G1) recognized the epitope F(19)VAQPVY(25), and McAbs 1G8 and 3A9 recognized P(42)IGAFTVK(49). Protein sequence alignment of VP1 with 16 EMCV isolates indicated that the epitope F(19)VAQPVY(25) was conserved in all the reference strains. The epitopes P(42)IGAFTVK(49) and V(2)ENAEK(7) only had 1 or 2 variable amino acid among the reference strains. The 3D model analysis results showed that these epitopes presented as spheres were shown within the context of the complete particle. Conclusions In this study, ten McAbs against EMCV VP1 were developed and three B-cells epitopes (2-7aa, 19-25aa and 42-49aa) were defined in VP1. All the results herein will promote the future investigations into the function of VP1 of EMCV and development of diagnostic methods of EMCV. [ABSTRACT FROM AUTHOR]

Progressive multifocal leukoencephalopathy is a currently untreatable infection of the brain. Here, we demonstrate in 2 patients that treatment with interleukin 7, JC polyomavirus (JCV) capsid protein VP1, and a Toll-like receptor 7 agonist used as adjuvant, was well tolerated, and showed a very favorable safety profile and unexpected efficacy that warrant further investigation. [ABSTRACT FROM AUTHOR]

Genotyping by VP1 fragment polymerase chain reaction (PCR) and nucleic acid sequencing to detect enterovirus (EV) genotypes was performed directly on 729 EV PCR positive cerebrospinal fluid (CSF) samples collected between 2007 and 2012 from Victorian hospital inpatients. The overall genotype identification rate from CSF‐positive material was 43%. The four most common genotypes identified were Echovirus 6 (24%), Echovirus 30 (17%), Echovirus 25 (10%), and Coxsackievirus A9 (10%), together comprising 61% of all EVs typed. The seasonal distribution of all EVs identified followed the recognized pattern of mainly summer epidemics. Three of the four predominant genotypes were present in each of the 6 years in which the study was conducted, with 20 other EV genotypes also detected, often in only a single year. Genotyping of EVs directly in CSF is faster, simpler and more sensitive than traditional virus neutralization assays performed on EV positive samples. [ABSTRACT FROM AUTHOR]

Porcine circovirus type 2 (PCV2) is the etiological agent of postweaning multisystemic wasting syndrome, a disease that causes huge economic damage in swine industry. A recombinant PCV2 expressing the neutralizing VP1 epitope (aa 141-160) of the foot-and-mouth disease virus (FMDV) was rescued using an infectious cloning technique. The PCV2 antigen and FMDV-VP1 antigenic epitope of the cloned strain recPCV2-CL-VP1 were confirmed by an immunoperoxidase monolayer assay (IPMA) and a capture enzyme-linked immunosorbent assay (ELISA). The morphological features of the recPCV2-CL-VP1 were not discernibly different from those of its parental strain (PCV2-CL). However, the recombinant virus could be differentiated from its parental virus by PCR and capture ELISA. The recPCV2-CL-VP1 was demonstrated to replicate stably in PK-15 cells through ten passages. An infection experiment using BALB/c mice showed that both recPCV2-CL-VP1 and PCV2-CL could replicate in the mice, cause various pathological changes, and induce a high level of anti-Cap antibodies. The recombinant virus emulsified with Freund's adjuvant was used to immunize BALB/c mice and induced antibodies against the FMDV-VP1 epitope. Hence, the recombinant PCV2 strain, which expressed the neutralizing FMDV-VP1 epitope, provides a valuable platform to develop novel genetic vaccines. [ABSTRACT FROM AUTHOR]

Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease caused by human enteroviruses (EV). This study aimed to describe the epidemiological features of HFMD and the genetic characteristics of Coxsackievirus A16 (CVA16) in Taiyuan, Shanxi, China, from 2010 to 2021. Descriptive epidemiological methods were used to analyze the time and population distribution of HFMD and the genetic characteristics of CVA16. Except being affected by the COVID-19 epidemic in 2020, HFMD epidemics were sporadic from January to March each year, and began to increase in April, with a major epidemic peak from May to August, which declined in September, followed by a secondary peak from October to December. The prevalence of EV infection was the highest in children aged one to five years (84.42%), whereas its incidence was very low in children under one year of age (5.48%). Enterovirus nucleic acid was detected by real-time reverse transcription polymerase chain reaction in 6641 clinical specimens collected from patients with HFMD from 2010 to 2021, and 4236 EV-positive specimens were detected, including 988 enterovirus A71 (EV-A71), 1488 CVA16, and 1760 other enteroviruses. CVA16 remains prevalent and has co-circulated with other EVs in Taiyuan from 2010 to 2021. A phylogenetic tree constructed based on the VP1 region showed that all CVA16 strains belonged to two different clades of the B1 genotype, B1a and B1b. They showed a nucleotide similarity of 86.5-100%, and an amino acid similarity of 96.9-100%. Overall, these findings add to the global genetic resources of CVA16, demonstrate the epidemiological characteristics of HFMD as well as the genetic features of CVA16 in Taiyuan City during 2010-2021, and provide supporting evidence for the prevention and control of HFMD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Guo, Cao, Liu, Xu, Zhao, Gao, Zuo, Song, Han, Zhang and Wang.)

Bovine enteroviruses, which belong to the Picornaviridae family, can cause clinical symptoms in cattle and are excreted in feces. In this study, a cytolytic virus was isolated from Madin-Darby bovine kidney (MDBK) cells from fecal samples of bovine with severe diarrhea and hemorrhagic intestinal mucosa that had been originally diagnosed with bovine viral diarrhea (BVD) by a bovine viral diarrhea virus Ag point-of-care test (IDEXX, American). Random priming PCR was used to amplify underlying viral sequences and identify the isolated virus. Phylogenetic analysis indicated that the isolated virus closely matches the EV-E2 species, which is different from other Chinese strains previously isolated. The newly identified virus was named HLJ-3531/2013. We infected the sulking mice with the isolated virus. Reverse-transcription PCR, hematoxylin and eosin (HE) staining, serum neutralization (SN) test, and virus isolation from various tissues revealed that HLJ-3531/2013 can infect the intestine, liver, and lung of suckling mice. The present work is the first to report the reproduction of clinical symptoms by an isolated virus in an experimental infection model of animals and lays a solid foundation for the development of the pathogenesis of bovine enteroviruses. [ABSTRACT FROM AUTHOR]

Objectives To study the characteristics and the mode of action of the anti-rhinovirus compound 4-[1-hydroxy-2-(4,5-dimethoxy-2-nitrophenyl)ethyl]benzonitrile (LPCRW_0005). Methods The antiviral activity of LPCRW_0005 was evaluated in a cytopathic effect reduction assay against a panel of human rhinovirus (HRV) strains. To unravel its precise molecular mechanism of action, a time-of-drug-addition study, resistance selection and thermostability assays were performed. The crystal structure of the HRV14/LPCRW_0005 complex was elucidated as well. Results LPCRW_0005 proved to be a selective inhibitor of the replication of HRV14 (EC50 of 2 ± 1 μM). Time-of-drug-addition studies revealed that LPCRW_0005 interferes with the earliest stages of virus replication. Phenotypic drug-resistant virus variants were obtained (≥30-fold decrease in susceptibility to the inhibitory effect of LPCRW_0005), which carried either an A150T or A150V amino acid substitution in the VP1 capsid protein. The link between the mutant genotype and drug-resistant phenotype was confirmed by reverse genetics. Cross-resistance studies and thermostability assays revealed that LPCRW_0005 has a similar mechanism of action to the capsid binder pleconaril. Elucidation of the crystal structure of the HRV14/LPCRW_0005 complex revealed the existence of multiple hydrophobic and polar interactions between the VP1 pocket and LPCRW_0005. Conclusions LPCRW_0005 is a novel inhibitor of HRV14 replication that acts as a capsid binder. The compound has a chemical structure that is markedly smaller than that of other capsid binders. Structural studies show that LPCRW_0005, in contrast to pleconaril, leaves the toe end of the pocket in VP1 empty. This suggests that extended analogues of LPCRW_0005 that fill the full cavity could be more potent inhibitors of rhinovirus replication. [ABSTRACT FROM PUBLISHER]

Background Enteroviruses have been implicated in the etiology of type 1 diabetes, supported by immunoreactivity of enteroviral protein in islets, but presence of enteroviral genome has rarely been reported. Failure to detect enterovirus with RT-PCR has been attributed to the possible presence of PCR inhibitors and that only few cells are infected. Objectives The aim of this study was to evaluate strategies for detection of enterovirus in human islets. Study design A scenario was modeled with defined infected islets among a large number of uninfected pancreatic cells and the sensitivity of immunohistochemistry and PCR for detection of enterovirus was evaluated. Results Enterovirus was detected with PCR when only one single human islet, infected in vitro with a low dose of virus, was mixed with an uninfected pancreatic biopsy. Enterovirus could not be detected by immunohistochemistry under the same conditions, demonstrating the superior sensitivity of PCR also in pancreatic tissue with only a small fraction of infected cells. In addition, we demonstrate that pancreatic cell culture supernatant does not cause degradation of enterovirus at 37 °C, indicating that under normal culture conditions released virus is readily detectable. Utilizing PCR, the pancreases of two organ donors that died at onset of type 1 diabetes were found negative for enterovirus genome despite islet cells being positive using immunohistochemistry. Conclusions These data suggest that PCR should be the preferred screening method for enterovirus in the pancreas and suggest cautious interpretation of immunostaining for enterovirus that cannot be confirmed with PCR. [ABSTRACT FROM AUTHOR]

A novel small molecule, H1PVAT, was identified as a potent and selective inhibitor of the in vitro replication of all three poliovirus serotypes, whereas no activity was observed against other enteroviruses. Time-of-drug-addition studies revealed that the compound interfered with an early stage of virus replication. Four independently-selected H1PVAT-resistant virus variants uniformly carried the single amino acid substitution I194F in the VP1 capsid protein. Poliovirus type 1 strain Sabin, reverse-engineered to contain this substitution, proved to be completely insensitive to the antiviral effect of H1PVAT and was cross-resistant to the capsid-binding inhibitors V-073 and pirodavir. The VP1 I194F mutant had a smaller plaque phenotype than wild-type virus, and the amino acid substitution rendered the virus more susceptible to heat inactivation. Both for the wild-type and VP1 I194F mutant virus, the presence of H1PVAT increased the temperature at which the virus was inactivated, providing evidence that the compound interacts with the viral capsid, and that capsid stabilization and antiviral activity are not necessarily correlated. Molecular modeling suggested that H1PVAT binds with high affinity in the pocket underneath the floor of the canyon that is involved in receptor binding. Introduction of the I194F substitution in the model of VP1 induced a slight concerted rearrangement of the core β-barrel in this pocket, which disfavors binding of the compound. Taken together, the compound scaffold, to which H1PVAT belongs, may represent another promising class of poliovirus capsid-binding inhibitors next to V-073 and pirodavir. Potent antivirals against poliovirus will be essential in the poliovirus eradication end-game. [ABSTRACT FROM AUTHOR]

Duck hepatitis A virus (DHAV) is an infectious pathogen causing fatal duck viral hepatitis in ducklings. Although both the inactivated vaccines and live attenuated vaccines have been used to protect ducklings, DHAV-1 and DHAV-3 still cause significant serious damage to the duck industry in China and South Korea. For rapid detection, differentiation, and epidemic investigation of DHAV in China, a genotypespecific 1-step duplex reverse-transcription (RT) PCR assay was established in this study. The sensitivity and specificity of the developed RT-PCR assay was evaluated with nucleic acids extracted from 2 DHAV reference strains, and 9 other infectious viruses and bacteria. The genotype-specific primers amplified different size DNA fragments encompassing the complete VP1 gene of the DHAV-1 or DHAV-3. The assay detected the liver samples collected from experimentally infected ducklings and dead ducklings collected from different regions of China. Sequence analysis of these DNA fragments indicated that VP1 sequences of DHAV-1 can be used to distinguish wild type and vaccine strains. The phylogenetic analysis of VP1 sequences indicated that the developed RT-PCR assay can be used for epidemic investigation of DHAV-1 and DHAV-3. The developed RT-PCR assay can be used as a specific molecular tool for simultaneous detection, differentiation, and sequencing the VP1 gene of DHAV-1 and DHAV-3, which can be used for understanding the epidemiology and evolution of DHAV [ABSTRACT FROM AUTHOR]

Polyomaviruses have so far only been isolated from mammals and birds. Typical for all members of this family is their double-stranded genome of approximately 5000 base-pairs which can be divided into an early region encoding at least two functional proteins, the large and small tumor antigens, and a late region encompassing genes for the capsid proteins VP1 and VP2. During the last 10 years several novel polyomaviruses have been described in non-human primates and man. This review compares the non-human primate polyomavirus genomes that have been completely sequenced with each other and with the genomes of human polyomaviruses. We predict the presence of protein- and microRNA-encoding sequences. Our analyses demonstrate that several genetically distinct groups of non-human primate polyomaviruses exist, that different polyomaviruses can infect the same non-human primate species but that most of their proteins display highly similar domains and motifs, indicating conservation of key functions. [ABSTRACT FROM AUTHOR]

Infectious bursal disease (IBD) is a highly contagious disease of chickens caused by the infectious bursal disease virus (IBDV). This study was conducted to characterize three IBDV strains from Iran. A reverse transcriptase-polymerase chain reaction (RT-PCR) procedure was used to amplify a 715-bp fragment of the VP1 gene from IBDV strains. Amplified VP1 fragments of the three Iranian IBDV strains were sequenced and compared with published sequences of IBDV strains from around the world, and their phylogenetic relationships were analyzed. Alignment of IBDV strains revealed 23 nucleotide differences between vvIBDV (except for IL and PT) and other non-vvIBDV strains. Two nucleotide positions, 863G and 1023A, were specific as JRMP07IR and JRMP14IR strains. All vvIBDVs differed (except for IL and PT strains) from non-vvIBDVs at aa (amino acids) positions 242E and 287A. In the three Iranian IBDV strains, aa positions 251R in both JRMP07IR and JRMP14IR, and 360L in JRMP14IR differed from those of other vvIBDVs. In phylogenetic analyses, all three Iranian strains clustered together with vvIBDVs. One Iranian strain, JRMP30IR, was more closely related to two European strains (HOL and UK661) and two south-east Asian strains (OKYM and ZJ2000). However, the other two Iranian strains, JRMP07IR and JRMP14IR, were closer to two Turkish strains (OA/G1 and OE/G2) and a Malaysian strain (UPM94). Further comprehensive investigations will provide researchers a better knowledge on the distribution, variability, and phylogenetic relationships of different IBDVs isolated in Iran and other parts of the world. [ABSTRACT FROM AUTHOR]

Background: Asthma exacerbations are associated with human rhinovirus (HRV) infections, and more severe exacerbations are associated with HRV-C. We have previously shown that the HR C-specific antibody response is low in healthy adult sera and the most of the antibody to HRV-C is cross-reactive with HRV-A. Objectives: To compare the antibody response to each HRV species in asthmatic and nonasthmatic children in whom the type of HRV infection was known. Methods: Total and specific IgG1 binding to HRV viral caps protein antigens of HRV-A, -B, and -C were tested in the plasma from nonasthmatic children (n = 47) and children presenting the emergency department with asthma exacerbations (n = 9 HRV, found in most of the children at the time of their exacerbation (72%), was analyzed using molecular typing. Results: Asthmatic children had higher antibody responses to HRV. The titers specific to HRV-A, and to a lesser extent -HRV-B, were higher than in nonasthmatic controls. The species-specific responses to HRV-C were markedly lower than titers to HRV-A and HRV-B in both asthmatic and nonasthmatic children (P < .001). The titers both at presentation and after convalescence were not associated with the HRV genotype detected during the exacerbation. Conclusions: The higher total anti-HRV antibody titers of asthmatic children and their higher anti-HRV-A and -B titers of show their development of a heightened antiviral immune response. The low species-specific HRV-C titers found in all groups, even when the virus was found, point to a different and possibly less efficacious immune response to this species. [ABSTRACT FROM AUTHOR]

Murine norovirus (MNV) was first found as a surrogate for human norovirus study. However, MNV infection was mostly prevalent in laboratory mice, and its immunomodulatory properties may affect the outcome of animal experiments. MNV surveillance had been performed in Europe, North America and some other countries, but not in China. Nowadays, the complete MNV virions had been used as antigen in MNV serological detection. However, the complexity in the preparation of virions might affect the antigen stability, and the virulence recovery of virion antigen had also been detected. In this study, the caspid VP1 protein was proved to be the mostly predominant antigen in MNV virions. An ELISA method using the recombination VP1 as antigen was developed (rVP1 ELISA). The rVP1 ELISA is more sensitive and less specific than the MNV virion-derived IFA method. To address the prevalence of MNV in China, a totally 600 mouse serum samples from Beijing area were tested by rVP1 ELISA and confirmed by IFA and WB. The MNV infection rate was 11.67%, but most of the MNV-positive samples were from experimental facilities (MNV rate=30.94%), not from commercial vendors (MNV rate=0.27%). Collectively, a sensitive rVP1 ELISA was developed in the current study, and the MNV investigation by rVP1 ELISA showed that MNV infection was mostly prevalent in the laboratory mice, especially the mice from experimental facilities in Beijing area in China. [ABSTRACT FROM AUTHOR]

Background The VP1 protein of enterovirus 71 (EV71) is an important immunodominant protein which is responsible for host-receptor binding. Nevertheless, the relationship between VP1 and neurovirulence is still poorly understood. In this study, we investigated the relationship between mutation of VP1 and neurovirulent phenotype of EV71 infection. Methods One hundred and eighty-seven strains from Genbank were included, with a clear clinical background. They were divided into two groups, one with nervous system symptoms and one with no nervous system symptoms. After alignment, the significance of amino acid variation was determined by using the X2 test and a phylogenetic tree was constructed with MEGA software (version 5.1). Results We showed no significant difference in neurovirulence between genotype B and C. Interestingly, we found that variations of E145G/Q, E164D/K and T292N/K were associated with nervous system infection in genotype B. In the case of genotype C, the N31D mutation increased the risk for nervous complications, whereas I262V mutation decreased the risk of nervous complications. We used a 3D model of VP1 to demonstrate the potential molecular basis for EV71 nervous system tropism. Conclusions Distinct variations are shown to be associated with neurovirulent phenotype in the different genotype. Detection of variation in genotypes and subtypes may be important for the prediction of clinical outcomes. [ABSTRACT FROM AUTHOR]

Background Enterovirus 71 (EV71) is the etiologic agent of hand-foot-and-mouth disease (HFMD) in the Asia-Pacific region, Many strategies have been applied to develop EV71 vaccines but no vaccines are currently available. Mucosal immunization of the VP1, a major immunogenic capsid protein of EV71, may be an alternative way to prevent EV71 infection. Results In this study, mucosal immunogenicity and protect function of recombinant VP1 protein (rVP1) in formulation with chitosan were tested and assessed in female ICR mouse model. The results showed that the oral immunization with rVP1 induced VP1-specific IgA antibodies in intestine, feces, vagina, and the respiratory tract and serum-specific IgG and neutralization antibodies in vaccinated mice. Splenocytes from rVP1-immunized mice induced high levels of Th1 (cytokine IFN-γ), Th2 (cytokine IL-4) and Th3 (cytokine TGF-β) type immune responses after stimulation. Moreover, rVP1-immunized mother mice conferred protection (survival rate up to 30%) on neonatal mice against a lethal challenge of 103 plaque-forming units (PFU) EV71. Conclusions These data indicated that oral immunization with rVP1 in formulation with chitosan was effective in inducing broad-spectrum immune responses and might be a promising subunit vaccine candidate for preventing EV71 infection. [ABSTRACT FROM AUTHOR]

Arabidopsis ABI3 and maize VP1 are orthologous transcription factors that regulate seed maturation. ABI3 and VP1 have a C-terminal B3 DNA binding domain and a conserved N-terminal co-activator/co-repressor (COAR) domain consisting of A1, B1, B2 sub-domains. The COAR domain mediates abscisic acid signaling via a physical interaction with ABI5-related bZIP proteins. In order to delineate the COAR and B3 domain dependent functions of VP1, we created site directed mutations in the B3 domain that disrupted DNA binding activity and characterized gene regulation by the mutant proteins in transgenic abi3 mutant Arabidopsis plants. In seeds, COAR domain function of VP1 mutants that lacked B3 DNA binding activity was sufficient for complementation of the desiccation intolerant seed phenotype of abi3. Similarly in seedlings, the B3 domain was dispensable for most VP1 induced gene expression and ectopic developmental phenotypes, except for a small subset of the genes that showed B3 dependent regulation. Unexpectedly, over-expression of the DNA-binding deficient VP1-K519R mutant protein caused quantitative changes in floral organ size including elongation of pistils and shortened stamen filaments that resulted in a self-incompatible longistyly flower morphology, a key component of heterostyly type self-incompatibility. [ABSTRACT FROM AUTHOR]

Highlights: [•] Both pan-enterovirus primers (5′ UTR) and EV71/CA16 specific primers were designed. [•] There was high consistency between the 5′ UTR and VP1 for the typing of EVs causing HFMD. [•] Samples were detected with serotype-specific VP1 primers based on the results for the 5′ UTRs. [•] Non-EV71/CA16 EVs related to HFMD can be identified effectively. [ABSTRACT FROM AUTHOR]

Duck hepatitis A virus type 1 (DHAV-1) is one of the main pathogens responsible for death in ducklings. Autophagy is a catabolic process that maintains cellular homeostasis, and the PI3KC3 protein plays an important role in the initiation of autophagy. DHAV-1 infection induces autophagy in duck embryo fibroblasts (DEFs) but the molecular mechanism between it and autophagy has not been reported. First, we determined that DHAV-1 infection induces autophagy in DEFs and that autophagy induction is dependent on the integrity of viral proteins by infecting DEFs with UV-inactivated or heat-inactivated DHAV-1. Then, in experiments using the pharmacological autophagy inducer rapamycin and the autophagy inhibitor chloroquine, autophagy inhibition was shown to reduce intracellular and extracellular DHAV-1 genome copies and viral titres. These results suggest that autophagy activated by DHAV-1 infection in DEFs affects DHAV-1 proliferation and extracellular release. Next, we screened the autophagy-inducing effects of the DHAV-1 structural proteins VP0, VP3, and VP1 and found that all DHAV-1 structural proteins could induce autophagy in DEFs but not the full autophagic flux. Finally, we found that VP1 promotes protein expression of PI3KC3 and Beclin1 by western blot experiments and that VP1 interacts with PI3KC3 by co-immunoprecipitation experiments; moreover, 3-MA-induced knockdown of PI3KC3 inhibited VP1 protein-induced autophagy in DEFs. In conclusion, the DHAV-1 structural protein VP1 regulates the PI3KC3 complex by interacting with PI3KC3 to induce autophagy in DEFs., (© 2022. The Author(s).)

Background: High diversity of VP1 protein among enteroviruses has been a barrier in developing universally effective antiviral drugs. To maintain structure stability during evolution, several residues of VP1 protein of enteroviruses are conserved. Therefore, investigation of highly conserved residues in VP1 protein may provide information for antiviral drug candidates against enteroviruses., Methods: To identify highly conserved amino acid sequences of the VP1 in enterovirus genus, the Consurf and CABS-flex 2.0 web software were applied. Through the combination with secondary structure information, we focused on conserved amino acids of VP1 property analysis., Results: Most conserved residues of VP1 were in the interior and interacted with VP2, VP3 and VP4 capsid proteins. Structure of EV-A71 (PDB code 4AED) showed conserved residues were at hydrophobic pocket and close to the junction between the loop and β-barrel. Interestingly, arginine was the most common conserved residue of VP1. Proline was the second most common conserved residue and was found in the loop and β-barrel intersection areas. VP1 protein flexibility was associated with the secondary structure. Conserved residues of VP1 in β-barrel showed significantly low flexibility., Conclusion: Through large scale sequence analysis, we identified the amino acid distribution and location of conserved residues in VP1. This knowledge can be extrapolated for the Enterovirus genus and may contribute to developing the potential compound as an anti-enteroviral agent., Competing Interests: Declaration of competing interest No potential conflict of interest relevant to this article was reported., (Copyright © 2022. Published by Elsevier B.V.)

Enterovirus genus has over one hundred genotypes and could cause several kinds of severe animal and human diseases. Understanding the role of conserved residues in the VP1 capsid protein among the enterovirus genus may lead to anti-enteroviral drug development. The highly conserved residues were found to be located at the loop and ß-barrel intersections. To elucidate the role of these VP1 residues among the enterovirus genus, alanine substitution reverse genetics (rg) variants were generated, and virus properties were investigated for their impact. Six highly conserved residues were identified as located near the inside of the canyon, and four of them were close to the ß-barrel and loop intersection. The variants rgVP1-R86A, rgVP1-P193A, rgVP1-G231A, and rgVP1-K256A were unable to be obtained, which may be due to disruption in the virus replication process. In contrast, rgVP1-E134A and rgVP1-P157A replicated well and rgVP1-P157A showed smaller plaque size, lower viral growth kinetics, and thermal instability at 39.5°C when compared to the rg wild type virus. These findings showed that the conserved residues located at the ß-barrel and loop junction play roles in modulating viral replication, which may provide a pivotal role for pan-enteroviral inhibitor candidate. [ABSTRACT FROM AUTHOR]

Background: Progressive multifocal leukoencephalopathy (PML) onset, caused by Polyomavirus JC (JCPyV) in patients affected by immune-mediated diseases during biological treatment, raised concerns about the safety profile of these agents. Therefore, the aims of this study were the JCPyV reactivation monitoring and the noncoding control region (NCCR) and viral protein 1 (VP1) analysis in patients affected by different immunemediated diseases and treated with biologics. Methods: We performed JCPyV-specific quantitative PCR of biological samples collected at moment of recruitment (t0) and every 4 months (t1, t2, t3, t4). Subsequently, rearrangements' analysis of NCCR and VP1 was carried out. Data were analyzed using X2 test. Results: Results showed that at t0 patients with chronic inflammatory rheumatic diseases presented a JCPyV load in the urine significantly higher (p⩽0.05) than in patients with multiple sclerosis (MS) and Crohn's disease (CD). It can also be observed a significant association between JC viruria and JCPyV antibodies after 1 year of natalizumab (p=0.04) in MS patients. Finally, NCCR analysis showed the presence of an archetype-like sequence in all urine samples, whereas a rearranged NCCR Type IR was found in colon-rectal biopsies collected from 2 CD patients after 16 months of infliximab. Furthermore, sequences isolated from peripheral blood mononuclear cells (PBMCs) of 2 MS patients with JCPyV antibody at t0 and t3, showed a NCCR Type IIR with a duplication of a 98 bp unit and a 66 bp insert, resulting in a boxB deletion and 37 T to G transversion into the Spi-B binding site. In all patients, a prevalence of genotypes 1A and 1B, the predominant JCPyV genotypes in Europe, was observed Conclusions: It has been important to understand whether the specific inflammatory scenario in different immunemediated diseases could affect JCPyV reactivation from latency, in particular from kidneys. Moreover, for a more accurate PML risk stratification, testing JC viruria seems to be useful to identify patients who harbor JCPyV but with an undetectable JCPyV-specific humoral immune response. In these patients, it may also be important to study the JCPyV NCCR rearrangement: in particular, Spi-B expression in PBMCs could play a crucial role in JCPyV replication and NCCR rearrangement [ABSTRACT FROM AUTHOR]

Aichi virus (AiV) is an emerging single-stranded, positive-sense, non-enveloped RNA virus in the Picornaviridae that causes acute gastroenteritis in humans. The first case of AiV infection in Taiwan was diagnosed in a human neonate with enterovirus-associated symptoms; the virus was successfully isolated and propagated. To establish a method to detect AiV, we analyzed the antigen epitope and generated a polyclonal antibody against AiV viral protein 1 (VP1). This peptide-purified anti-AiV VP1 antibody showed high specificity against AiV VP1 without cross-reaction to nine other tested strains of Picornaviruses. The anti-AiV VP1 antibody was used in immunofluorescence analysis, immunoblotting, and enzyme-linked immunosorbent assay to elucidate the cell tropism and replication kinetics of AiV. Use of the anti-AiV VP1 antibody also revealed AiV infection restriction with interferon type I and polyI/C antiviral treatment. The AiV infection and detection system may provide an in vitro platform for AiV virology study. [ABSTRACT FROM AUTHOR]

Highlights: [•] The VP3 is the cross-reacting antigen in the EV71 IgM-capture ELISA with CVA16 serum. [•] The VP1 detection method is as sensitive as the virus-antibody detection method. [•] The VP1 detection method can resolve the false-positive problem. [ABSTRACT FROM AUTHOR]

The purpose of this research was to develop a new type of recombinant adenovirus vaccine against footand- mouth disease (FMD) virus and confirm whether both 2A and 3C proteases can fully process FMDV P1 polyprotein into VP1 protein. We constructed and characterized recombinant adenoviruses, designated as rAd-P1, rAd-P1-2A, rAd-L-P1, rAd-L-2A, and rAd-3C. The construct was further confirmed by the enzyme digestion, polymerase chain reaction (PCR) testing, sequencing, and transfection. The infective replicationdefective adenovirus rAd-3C was used to co-infect Vero cells with rAd-P1, rAd-P1-2A, rAd-L-P1, and rAd-L- 2A, respectively; the supernatant of cracked cells was then collected to immunize mice. Notably, the supernatant of the Vero cells co-infected with rAd-L-2A/rAd-3C or rAd-P1-2A/rAd-3C was shown to induce specific humoral and cellular immune responses in the study animals. Most importantly, we confirmed that 3C protease successfully processed P1 polyprotein into VP1 protein without L protein only under the precondition of 2A protease; however, P1-2A and L-2A polyprotein were not fully processed. Our study highlighted that P1 polyprotein cannot be fully processed into structural protein VP1 only under the condition of 2A and 3C proteases. The results also suggest that the recombinant adenovirus may be an attractive candidate as a vaccine for preventing the disease associated with FMD virus infection. [ABSTRACT FROM AUTHOR]

The Merkel cell polyomavirus (MCPyV), identified in humans in 2008, is associated with a relatively rare but aggressive neuroendocrine skin cancer, the Merkel cell carcinoma (MCC). MCC incidence is increasing due to the advancing age of the population, the increase in damaging sun exposure and in the number of immunocompromised individuals. MCPyV must be considered as the etiological agent of MCC and thus is the first example of a human oncogenic polyomavirus. MCPyV infection is common, and seroprevalence studies indicate that widespread exposure begins early in life. The majority of adults have anti-MCPyV antibodies and there is a growing body of evidence that healthy human skin harbors resident or transient MCPyV suggesting that MCPyV infection persists throughout life. However, the mode of transmission, the host cells, and the latency characteristics of this virus remain to be elucidated. In addition, it is still not clear whether MCPyV is associated with diseases or lesions other than Merkel cell carcinoma. The etiologic role of MCPyV in MCC opens up opportunities to improve the understanding of this cancer and to potentially improve its treatment. [ABSTRACT FROM AUTHOR]

Abstract: The Foot-and-mouth disease virus (FMDV) causes important economical losses in livestock farming. In order to develop a novel subunit vaccine against FMDV, we constructed recombinant baculoviruses that display the protein VP1 of FMDV on their surface, with either polar (fused to gp64) or nonpolar (fused to anchor membrane from VSV-G protein) distribution. Insect cells infected with the different recombinant baculoviruses expressed VP1 fusion protein to high levels. However, the recombinant VP1 protein was not carried by budded virions. Subcellular localization of VP1 revealed that the trafficking of the fusion protein to the cell plasma membrane was impaired. Our results suggest that VP1 contains cryptic domains that interfere with protein secretion and subsequent incorporation into budded baculoviruses. [Copyright &y& Elsevier]

Highlights: [•] Codon optimization of DHAV VP1 adapting to the codon usage bias of E. coli. [•] The expression level of the opti-VP1 gene was significantly increased in E. coli. [•] The His-tagged VP1 protein has good antigencity and immunogenicity. [Copyright &y& Elsevier]

Abstract: Infectious bursal disease virus (IBDV) is a birnavirus that causes immunosuppressive disease in chickens. The emergence of very virulent IBDV (vvIBDV) has brought new challenges for this disease. The molecular determinants for the high pathogenicity of vvIBDV are not fully understood. Previous studies focused mostly on the VP2 protein on segment A, but recent evidence suggests that segment B also plays an important role. Previously we identified eight amino acid changes in the VP1 protein of vvIBDV. In this study, we investigated effect of amino acids substitutions in VP1 on viral replication and pathogenicity. We identified a Valine to Isoleucine substitution at amino acid position 4 (V4I) of VP1 that attenuates viral pathogenicity and reduces viral replication in SPF chickens but increases viral replication in CEF cells. This study confirms that VP1 of segment B play an important role in viral replication and pathogenicity of vvIBDV. [Copyright &y& Elsevier]