A heat-induced Mutation on VP1 of FMDV Serotype O Enhanced Capsid Stability and the Immunogenicity

Foot-and-mouth disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals that cause a significant economic burden globally. Vaccination is the most effective FMD control strategy. However, FMDV particles are prone to dissociate when appropriate physical or chemical conditions are unavailable, such as an incomplete cold chain. Such degraded vaccines result in compromised herd vaccination. Therefore, thermostable FMD particles are needed for use in vaccines. This study generated thermostable FMDV mutants (M3 and M10) by serial passages at high temperature, subsequent amplification, and purification. Both mutants contained an alanine to threonine mutation at position 13 in VP1 (A1013T), although M3 contained 3 additional mutations. The selected mutants showed improved stability and immunogenicity in neutralizing antibody titers, compared with the wild-type (wt) virus. The sequencing analysis and cryo-electron microscopy showed that the mutation of alanine to threonine at the 13th amino acid (aa) in VP1 protein (A1013T) is critical for the capsid stability of FMDV. Virus-like particles (VLPA1013T) containing A1013T also showed significantly improved stability to heat treatment. This study demonstrated that Thr at the 13th amino acid of VP1 could stabilize the capsid of FMDV. Our findings will facilitate the development of a stable vaccine against FMDV serotype O. IMPORTANCE Foot-and-mouth disease (FMD) serotype O is one of the global epidemic serotypes, and cause significant economic loss. Vaccination plays a key role in the prevention and control of FMD. However, the success of vaccination mainly depends on the quality of the vaccine. Here, the thermostable FMDV mutants (M3 and M10) were selected through thermal-screening at high temperatures with improved stability and immunogenicity compared to the wild-type virus. The results of multi-sequence alignment and Cryo-EM analysis showed that the "Thr" substitution at the 13th amino acid in VP1 protein is critical for the capsid stability of FMDV. For thermolabile type O FMDV, this major discovery will aid the development of its thermostable vaccine.

Treatment of 27 Different Types of Cancer

BackgroundThis research paper analyzes how to treat cancer with a virus. It is known since the 1960s that viruses could be used to fight against cancers.MethodsTo answer this question, we analyzed the receptors that mutates when the genetic code becomes corrupt, then we analyzed the standard VP1 protein of two viruses of the same family. After that, we combined these two elements. Then we studied the REP genes and their impact on the virus entrance and replication. Finally, we examined the protocol of the synthesis of a rAAV. ResultsOur results showed that the protocol is applicable and that we would obtain a virus specially designed to kill the cancer cells. This virus would have a fully operational DNA, which would contain the VP1/2/3 genomic code, the REP genes and the ITR regions. ConclusionThis research is only theoretical, and all the steps and methods are based on a strong theoretic basis. The experimentation has not been made. We did not have the material to test them, but we tried to take all the impacting factors in consideration. Our study has shown that a treatment against cancer consisting of a virus could be possible.

Foot-and-Mouth Disease Virus Structural Protein VP1 Destroys the Stability of TPL2 Trimer by Degradation TPL2 to Evade Host Antiviral Immunity

Tumor progression locus 2 (TPL2) is a serine/threonine kinase that belongs to the mitogen-activated protein 3 kinase (MAP3K) family, and it plays an important role in pathogen infection. The trimer complex of TPL2, p105, and ABIN2 is essential for maintenance of TPL2 steady-state levels and host cell response to pathogens. Foot-and-mouth disease virus (FMDV) is a positive-strand RNA virus of the family Picornaviridae that encodes proteins capable of antagonizing host immune responses to achieve infection. The VP1 protein of FMDV is a multifunctional protein that can bind host cells and induce an immune response as well as cell apoptosis. However, the role and mechanisms of TPL2 in FMDV infection remain unknown. Here, we determined that FMDV infection could inhibit TPL2, p105, and ABIN2 at the transcription and protein levels, while VP1 could only inhibit TPL2, p105 and ABIN2 at protein level. TPL2 inhibited the replication of FMDV in vivo and in vitro, the 268 to 283 amino-acid region in the TPL2 kinase domain was essential for interaction with VP1. Moreover, VP1 promoted K48-linked polyubiquitination of TPL2 and degraded TPL2 by the proteasome pathway. However, VP1-induced degradation of p105 and ABIN2 was independent of proteasome, autophagy, lysosome, and caspase-dependent pathways. Further studies showed that VP1 destroyed the stability of the TPL2-p105-ABIN2 complex. Taken together, these results revealed that VP1 antagonized TPL2-meditated antivirus activity by degrading TPL2 and destroying its complex. These findings may contribute to understand FMDV-host interactions and improve development of a novel vaccine to prevent FMDV infection. Importance Virus-host interactions are critical for virus infection. This study was the first to demonstrate the antiviral effect of host TPL2 during FMDV replication by increasing production of interferons and antiviral cytokines. Both FMDV and VP1 protein can reduce host TPL2, ABIN2 and p105 to destroy TPL2-p105-ABIN2 trimer complex. VP1 interacted with TPL2 and degrade TPL2 via proteasome pathway to repress TPL2-mediated antivirus activity. This study provided new insights into FMDV immune evasion mechanisms, elucidating new informations regarding FMDV counteraction of host antivirus activity.

A Systematic Review and Meta-analysis of the Protective Effect of FMDV VP1 on Animals

The FMDV VP1 protein has different structures which could decrease or increase the immune response. We undertook a meta-analysis to evaluate the protective effect of VP1 on the FMDV. A systematic search of the PubMed, Embase, CNKI and Wan fang DATA was conducted up to April 2020. Experimental studies involving the VP1 protection effect on FMDV were included. Extracted data were analyzed using Rev-Man 5.3 software. Chi-square tests were used to analyze the heterogeneity among the documents. The fixed-effect model was used for meta-analysis to find the combined effect value and 95% confidence interval. Sensitivity analysis was performed on the differences in the combined values of model effects, and the inverted funnel chart method was used to assess the publication bias of the included literature. A total of 12 articles were included for meta-analysis. The results of showed that VP1 had a protective effect on FMDV [MH = -0.66, 95% CI = (−0.75, -0.56), P < 0.00001]. Sensitivity analysis showed that the results were robust. The funnel graph method showed that the published literature had a small publication bias and met the requirements of this study. It is necessary to study the epitopes of VP1 to produce new vaccines. VP1 could protect animals from FMDV attacks. It is necessary to study the VP1 protein and its epitopes and use it as a new vaccine and diagnostic product.

Major Capsid Protein Synthesis from the Genomic RNA of Feline Calicivirus

ABSTRACT Caliciviruses have a positive-strand RNA genome with a length of about 7.5 kb that contains 2, 3, or 4 functional open reading frames (ORFs). A subgenomic mRNA (sg-RNA) is transcribed in the infected cell, and both major capsid protein viral protein 1 (VP1) and minor capsid protein VP2 are translated from the sg-RNA. Translation of proteins from the genomic RNA (g-RNA) and from the sg-RNA is mediated by the RNA-linked viral protein VPg (virus protein, genome linked). Most of the calicivirus genera have translation mechanisms leading to VP1 expression from the g-RNA. VP1 is part of the polyprotein for sapoviruses, lagoviruses, and neboviruses, and a termination/reinitiation mechanism was described for noroviruses. Vesiviruses have no known mechanism for the expression of VP1 from the g-RNA, and the Vesivirus genus is the only genus of the Caliciviridae that generates VP1 via a precursor capsid leader protein (LC-VP1). Analyses of feline calicivirus (FCV) g-RNA translation showed a low level of VP1 expression with an initiation downstream of the original start codon of LC-VP1, leading to a smaller, truncated LC-VP1 (tLC-VP1) protein. Deletion and substitution analyses of the region surrounding the LC-VP1 start codon allowed the identification of sequences within the leader protein coding region of FCV that have an impact on VP1 translation frequency from the g-RNA. Introduction of such mutations into the virus showed an impact of strongly reduced tLC-VP1 levels translated from the g-RNA on viral replication. IMPORTANCE Caliciviruses are a cause of important diseases in humans and animals. It is crucial to understand the prerequisites of efficient replication of these viruses in order to develop strategies for prevention and treatment of these diseases. It was shown before that all caliciviruses except vesiviruses have established mechanisms to achieve major capsid protein (VP1) translation from the genomic RNA. Here, we show for the first time that a member of the genus Vesivirus also has a translation initiation mechanism by which a precursor protein of the VP1 protein is expressed from the genomic RNA. This finding clearly points at a functional role of the calicivirus VP1 capsid protein in early replication, and we provide experimental data supporting this hypothesis.

Molecular Characteristics of VP1 Region of Enterovirus 71 Strains in China

Background Enterovirus 71 (EV71) is the most common causative agent of severe and fetal hand, foot, and mouth disease (HFMD) outbreaks worldwide, and the VP1 protein, a capsid protein of EV71, is responsible for the genotype of EV71, which is important for vaccine selection and effectiveness. We performed an observational study of the genetic characteristics and genotype of EV71 isolates in China. Methods The VP1 gene sequences of 3712 EV71 virus strains from China, excluding repetitive sequences, and 30 known EV71 genotypes, as reference strains, between 1986 and 2019 were obtained from GenBank. A phylogenetic tree, amino acid homology, genetic variation and genotype analysis of the EV71-VP1 protein were performed with MEGA 6.0 software. Results The amino acid identity of all Chinese EV71 strains was 88.33%-100%, 93.47%-100% with the vaccine strain H07, and 93.04%-100% with the vaccine strains FY7VP5 and FY-23K-B. Since 2000, the prevalent strains of EV71 were mainly the C4 genotype; the C4a subgenotype was predominant, the C4b subgenotype was the second, and other subgenotypes appeared sporadically between 2005 and 2018 in mainland China. The B4 genotype was the main genotype in Taiwan, and the epidemic strains were constantly changing. Some amino acid variations in VP1 of EV71 occurred with high frequencies: A289T (20.99%), H22Q (16.49%), A293S (15.95%), S283T (15.11%), V249I (7.76%), N31D (7.25%), and E98K (6.65%). Conclusion The C4 genotype of EV71 in China can match the vaccine, which can effectively control EV71 epidemiology. However, the efficacy of the vaccine strain is partially affected by the continuous change in epidemic strains in Taiwan, China. These studies suggested that the genetic characteristics of the EV71-VP1 region should be continuously monitored, which is critical for epidemic control and vaccine design against EV71 infection in children.

Production of foot-and-mouth disease virus SAT2 VP1 protein

The seven serotypes of foot-and-mouth disease virus (FMDV) differ on the surface exposed regions on the VP1, 2 and 3 proteins. Amongst the three, the VP1 protein has been produced the most for use in serotyping assays for some of the Euro-Asian serotypes. In this study the VP1 protein of the FMDV SAT2/ZIM/7/83 was expressed in Escherichia coli BL21 cells in Luria broth and EnPresso® B media in shake flasks. Production was further developed and the VP1 protein was produced at 2.15 g L−1 in fed-batch fermentations at 2 L scale. The protein formed insoluble inclusion bodies that were isolated, denatured and refolded. When tested in ELISA, the protein was found to be highly reactive with serum from a SAT2 vaccinated guinea pig, and not reactive to SAT1 and SAT3 antisera. These results open avenues to evaluate recombinantly expressed VP1 proteins for differentiation of the three Southern African Territories serotypes of FMDV that co-occur in Southern and East Africa. In addition, this could mitigate the need for employing virus as reagent, or having to raise reagent antibodies.

Efficient Production of Human Norovirus-Specific IgY in Egg Yolks by Vaccination of Hens with a Recombinant Vesicular Stomatitis Virus Expressing VP1 Protein

Human norovirus (HuNoV) is responsible for more than 95% of outbreaks of acute nonbacterial gastroenteritis worldwide. Despite major efforts, there are no vaccines or effective therapeutic interventions against this virus. Chicken immunoglobulin Y (IgY)-based passive immunization has been shown to be an effective strategy to prevent and treat many enteric viral diseases. Here, we developed a highly efficient bioreactor to generate high titers of HuNoV-specific IgY in chicken yolks using a recombinant vesicular stomatitis virus expressing HuNoV capsid protein (rVSV-VP1) as an antigen. We first demonstrated that HuNoV VP1 protein was highly expressed in chicken cells infected by rVSV-VP1. Subsequently, we found that White Leghorn hens immunized intramuscularly with rVSV-VP1 triggered a high level of HuNoV-specific yolk IgY antibodies. The purified yolk IgY was efficiently recognized by HuNoV virus-like particles (VLPs). Importantly, HuNoV-specific IgY efficiently blocked the binding of HuNoV VLPs to all three types (A, B, and O) of histo-blood group antigens (HBGAs), the attachment factors for HuNoV. In addition, the receptor blocking activity of IgY remained stable at temperature below 70 °C and at pH ranging from 4 to 9. Thus, immunization of hens with VSV-VP1 could be a cost-effective and practical strategy for large-scale production of anti-HuNoV IgY antibodies for potential use as prophylactic and therapeutic treatment against HuNoV infection.