Evolutionary and dynamic processes are inherent to the virus-host interaction. For successful infection, viruses need to engage in a conflict with their host. Eukaryotic hosts possess a multitude of protective mechanisms to counter viral incursions. The antiviral defenses of the host include nonsense-mediated mRNA decay (NMD), an evolutionarily conserved mechanism for RNA quality control in eukaryotic cells. The accuracy of mRNA translation hinges on NMD's ability to remove abnormal mRNAs characterized by the presence of pre-mature stop codons. RNA viruses' genomes often include internal stop codons (iTCs). Similar to a premature stop codon found in irregular RNA transcripts, the existence of iTC would trigger NMD to break down viral genomes containing iTC. A small percentage of viruses have exhibited responsiveness to antiviral defenses mediated by NMD, while a different group of viruses have developed unique cis-acting RNA structures or trans-acting viral proteins to evade or bypass the NMD response. Recent studies have significantly enhanced our knowledge of the NMD-virus interplay. This review compiles the current state of viral RNA degradation mediated by NMD, categorizing the various molecular strategies used by viruses to disrupt the antiviral NMD defense, thereby promoting enhanced infection.
One of the most crucial neoplastic poultry diseases, Marek's disease (MD), results from infection by the pathogenic Marek's disease virus type 1 (MDV-1). The MDV-1-encoded unique Meq protein's status as the primary oncoprotein highlights the critical need for Meq-specific monoclonal antibodies (mAbs) for deciphering MDV's pathogenesis and oncogenesis. Immunogens derived from synthesized polypeptides within the conserved hydrophilic domains of the Meq protein, combined with hybridoma methodology and an initial screening process using cross-immunofluorescence assays (IFA) on MDV-1 viruses lacking the Meq protein, which were created using CRISPR/Cas9 gene editing technology, yielded a total of five positive hybridoma cell lines. The four hybridomas, 2A9, 5A7, 7F9, and 8G11, demonstrated, through IFA staining of Meq-overexpressing 293T cells, the production of Meq-specific antibodies, confirming their ability to secrete said antibodies. The confocal microscopic analysis of these antibody-stained cells confirmed the presence of Meq protein exclusively within the nuclei of MDV-infected CEF cells and MDV-transformed MSB-1 cells. Furthermore, two mAb-producing hybridoma clones, specifically 2A9-B12 derived from 2A9 and 8G11-B2 derived from 8G11, displayed an exceptional ability to target Meq proteins found within MDV-1 strains varying in their virulence levels. The data presented here illustrates a new, efficient approach to generating future-generation mAbs against viral proteins using synthesized polypeptide immunization, combined with cross-IFA staining on CRISPR/Cas9 gene-edited viruses.
The viruses Rabbit haemorrhagic disease virus (RHDV), European brown hare syndrome virus (EBHSV), rabbit calicivirus (RCV), and hare calicivirus (HaCV), part of the Lagovirus genus within the Caliciviridae family, are known for causing severe diseases in rabbits and multiple hare (Lepus) species. Historically, lagovirus classification relied on partial genome analysis, specifically the VP60 coding sequences, which distinguished two genogroups: GI (containing RHDVs and RCVs) and GII (including EBHSV and HaCV). This study details a phylogenetic classification of Lagovirus strains. Examining complete genome sequences of 240 strains identified between 1988 and 2021, we establish four major clades: GI.1 (classic RHDV), GI.2 (RHDV2), HaCV/EBHSV, and RCV. The GI.1 clade is further divided into four subclades (GI.1a-d) and GI.2 into six subclades (GI.2a-f), resulting in a comprehensive phylogenetic structure. A further observation from the phylogeographic analysis suggested that the EBHSV and HaCV strains share their evolutionary roots with GI.1, whereas RCV is phylogenetically linked to GI.2. Furthermore, all 2020-2021 RHDV2 outbreak strains within the United States exhibit a connection to the strains observed in both Canada and Germany, whereas RHDV strains isolated in Australia are linked to the RHDV strain, a haplotype shared by the USA and Germany. Using the entire genome sequences, we located six recombination points within the coding regions for VP60, VP10, and RNA-dependent RNA polymerase (RdRp). The amino acid variability study demonstrated that the variability index for the ORF1-encoded polyprotein and the ORF2-encoded VP10 protein each exceeded 100, highlighting substantial amino acid divergence and the emergence of novel strains. This research update details the phylogenetic and phylogeographic characteristics of Lagoviruses, enabling the exploration of their evolutionary history and offering potential insights into the genetic determinants of their emergence and re-emergence.
A substantial proportion of the global population, nearly half, is at risk of infection from dengue virus serotypes 1 to 4 (DENV1-4), but the licensed tetravalent dengue vaccine fails to protect those who haven't previously contracted DENV. For a prolonged duration, the development of intervention strategies was constrained by the absence of a suitable small animal model. The inability of DENV to counteract the type I interferon response in wild-type mice prevents its replication. Due to a deficiency in type I interferon signaling (Ifnar1 knockouts), mice are significantly more susceptible to Dengue virus infection; however, their immunocompromised state complicates the assessment of immune responses following experimental vaccinations. Adult wild-type mice were pre-treated with MAR1-5A3, a non-cell-depleting antibody inhibiting IFNAR1, and subsequently infected with the DENV2 strain D2Y98P to develop an alternative model for vaccine testing. Employing this approach, immunocompetent mice can be vaccinated, and subsequently, type I IFN signaling can be inhibited before infection exposure. wound disinfection Despite the swift demise of Ifnar1-/- mice due to infection, MAR1-5A3-treated mice displayed no signs of illness, only to eventually exhibit seroconversion. in vitro bioactivity Infectious virus was isolated from the sera and visceral organs of Ifnar1-/- mice, contrasting with the complete absence of virus in MAR1-5A3-treated mice. The MAR1-5A3 treatment, despite efforts, resulted in mouse samples exhibiting high viral RNA levels, a clear indication of active viral replication and its spread. A transiently immunocompromised mouse model of DENV2 infection will prove valuable in the pre-clinical assessment of cutting-edge vaccines and novel antiviral treatments.
A noticeable escalation in the prevalence of flavivirus infections has been observed worldwide recently, demanding significant attention from global public health systems. The four dengue virus serotypes, Zika virus, West Nile virus, Japanese encephalitis virus, and yellow fever virus, all being flaviviruses, are prominently transmitted by mosquitoes and are clinically significant. check details Previously, no effective antiflaviviral drugs existed for treating flaviviral infections; thus, a highly immunogenic vaccine serves as the most effective preventative measure against the diseases. Over recent years, vaccine research for flaviviruses has seen substantial progress, resulting in multiple vaccine candidates that have shown encouraging results in preclinical and clinical trials. The current status of vaccines against mosquito-borne flaviviruses, which endanger human health, is evaluated in this review, encompassing advancements, safety profiles, efficacy, advantages, and disadvantages.
Hyalomma anatolicum is the primary vector responsible for transmitting Theileria annulata, T. equi, and T. Lestoquardi in animals and the Crimean-Congo hemorrhagic fever virus in humans. Recognizing the gradual decline in the effectiveness of available acaricides against field tick populations, the advancement of phytoacaricides and vaccines is considered crucial in implementing integrated tick management solutions. In order to stimulate both cellular and humoral immune responses in the host against *H. anatolicum*, this study employed two multi-epitopic peptides, namely VT1 and VT2. Through in silico analysis of allergenicity (non-allergen, antigenic (046 and 10046)), physicochemical properties (instability index 2718 and 3546), and TLR interactions (determined via docking and molecular dynamics), the immune-stimulating potential of the constructs was evaluated. Rabbits immunized with VT1 and VT2 protocols using MEPs mixed with 8% MontanideTM gel 01 PR demonstrated immunization efficacies of 933% and 969%, respectively, against H. anatolicum larvae. The efficacy of the VT1 and VT2 immunized rabbits against adults was 899% and 864%, respectively. There was a marked 30-fold upsurge and a decreased anti-inflammatory cytokine IL-4 level to 0.75 of the former. The potential for MEP to stimulate the immune system, along with its demonstrated efficacy, suggests its possible usefulness in tick control.
Within the molecular structures of Comirnaty (BNT162b2) and Spikevax (mRNA-1273), COVID-19 vaccines, a full-length SARS-CoV-2 Spike (S) protein is encoded. In a real-world study of S-protein expression, two cell lines were subjected to 24 hours of treatment with two dosages of each vaccine, subsequently being evaluated for differences in expression via flow cytometry and ELISA. The three vaccination centers in Perugia, Italy, provided us with vaccines from vials containing residual quantities, following the completion of vaccinations. Intriguingly, the S-protein's presence was not limited to the cell membrane, but also apparent within the supernatant. Spikevax-treated cells uniquely exhibited a dose-dependent expression profile. Moreover, the expression levels of the S-protein were significantly elevated in both the cellular and supernatant samples of Spikewax-treated cells compared to those treated with Comirnaty. Following vaccine treatment, differing S-protein expression levels might stem from variable lipid nanoparticle effectiveness, disparate mRNA translation rates, or the loss of lipid nanoparticle properties and mRNA integrity during transport, storage, or dilution, potentially accounting for the slight discrepancies in efficacy and safety between Comirnaty and Spikevax.