Capsid Research Articles

A humanized neutralizing antibody protects against human adenovirus type 7 infection in humanized desmoglein-2 and CD46 double-receptor transgenic mice.

Human adenovirus type 7 (HAdV7) has become a major public health threat due to its widespread transmission, severe associated pneumonia, and a lack of effective anti-HAdV7 drugs. The aim of the current study is to design a humanized monoclonal antibody (mAb) demonstrating efficacy against HAdV-7 infections in vitro and in vivo. The humanized neutralizing antibody, 3G5-hu, was derived from the murine mAb 3G5. Antibody activity was evaluated using a flow cytometry-based neutralization (FCN) assay to identify humanized mAbs retaining potent neutralizing activity. Additionally, a humanized hDSG2/hCD46 dual-receptor transgenic mouse model was developed to simulate HAdV-7 infection. Using recombinant HAdV-7 expressing enhanced green fluorescent protein and clinically isolated wild-type HAdV-7, the half-maximal effective concentration of 3G5-hu against HAdV-7 was determined to be < 30 ng/mL. Notably, 3G5-hu exhibits high specificity for the hexon protein of the HAdV-7 capsid (affinity: KD = 9.02 × 10- 11 M). Microneutralization studies with wild-type HAdV-7 and rAd7EGFP confirmed that humanized mAb 3G5-hu neutralizes 10-30 ng/mL HAdV-7 (approximately 67-200 pM). Furthermore, hDSG2/hCD46 double-receptor transgenic mice are more susceptible to HAdV-7 infection than single-receptor transgenic mice. Meanwhile, the humanized mAb 3G5-hu provides good protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. The newly designed humanized mAb 3G5-hu specifically neutralizes HAdV-7 in vitro and in vivo. 3G5-hu elicits protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. The findings of this study provide insights to guide the future development of preventative and therapeutic treatments for HAdV-7 infection.

Identification and Characterization of Linear Epitopes of Monoclonal Antibodies Against African Horse Sickness Virus Serotype 1 VP2 Protein

African horse sickness (AHS) is an acute, fatal, contagious disease of animals of the family Equidae and is caused by infection with the African horse sickness virus (AHSV). Based on the outer capsid protein VP2, AHSV is classified into nine serotypes (AHSV−1 to −9) with little or no serological cross-reactivity between them. In 2020, AHS outbreaks caused by AHSV−1 were reported in Thailand and Malaysia, marking the first occurrences of AHS in Southeast Asia. However, little is known about the antigenic profile of AHSV−1 VP2. In this study, a recombinant VP2 protein was expressed in Escherichia coli and used as an immunogen, and three monoclonal antibodies (mAbs), designated 7D11, 10A9, and 9E7, against AHSV−1 VP2, were generated. These three mAbs were then successfully used in IFA, WB, and ELISA for the detection of AHSV−1 VP2. Two overlapping linear epitopes, 670NEFDFE675 (E670–675) recognized by 9E7 and 670NEFDF674 (E670–674) recognized by 7D11 and 10A9, were identified through truncation of GST-fused VP2. Amino acid sequence alignment shows that the 670NEFDFE675 motif is completely conserved within AHSV−1 but is highly divergent in other AHSV serotypes. Our studies provide an important tool for basic research into AHSV−1 and for the diagnosis of AHSV−1.

Modeling extrahepatic hepatitis E virus infection in induced human primary neurons

Hepatitis E virus (HEV) infections are one of the most common causes of acute viral hepatitis, annually causing over 3 million symptomatic cases and 70,000 deaths worldwide. Historically, HEV was described as a hepatotropic virus, but has recently been associated with various extrahepatic manifestations including neurological disorders such as Guillain-Barré syndrome and neuralgic amyotrophy. However, the underlying pathogenesis of these neurological diseases remains largely unknown. The aim of this study was to investigate extrahepatic HEV manifestations in a neuronal model system using human-induced primary neurons (iPNs). Renal epithelial cells from human urine were reprogrammed to induced pluripotent stem cells to generate neuronal progenitor cells, which were subsequently differentiated into iPNs over 21 d. These iPNs supported HEV infection preferentially in neurite-bearing cells. Transcriptional profiling of the neuronal development process as well as viral infection dynamics in iPNs uncovered a lack of antiviral innate immune responses to HEV infection with only an intrinsic expression of distinct interferon-regulated genes and signaling molecules. Viral open reading frame 2 encoded capsid protein could be visualized by volumetric three-dimensional reconstitution within the neurites, which were reduced in length in an HEV inoculation-dependent manner. In conclusion, this neuron-derived human model system provides a powerful tool for studying extrahepatic manifestations of HEV infection. It further indicates a potential mechanism of pathogenesis driven by the interaction between host and viral factors.

Explicit description of viral capsid subunit shapes by unfolding dihedrons.

Viral capsid assembly and the design of capsid-based nanocontainers critically depend on understanding the shapes and interfaces of constituent protein subunits. However, a comprehensive framework for characterizing these features is still lacking. Here, we introduce a novel approach based on spherical tiling theory that explicitly describes the 2D shapes and interfaces of subunits in icosahedral capsids. Our method unfolds spherical dihedrons defined by icosahedral symmetry axes, enabling systematic characterization of all possible subunit geometries. Applying this framework to real T = 1 capsid structures reveals distinct interface groups within this single classification, with variations in interaction patterns around 3-fold and 5-fold symmetry axes. We validate our classification through molecular docking simulations, demonstrating its consistency with physical subunit interactions. This analysis suggests different assembly pathways for capsid nucleation. Our general framework is applicable to other triangular numbers, paving the way for broader studies in structural virology and nanomaterial design.

Cryo-EM of human rhinovirus reveals capsid-RNA duplex interactions that provide insights into virus assembly and genome uncoating.

The cryo-EM structure of the human rhinovirus B14 determined in this study reveals 13-bp RNA duplexes symmetrically bound to regions around each of the 30 two-fold axes in the icosahedral viral capsid. The RNA duplexes (~12% of the ssRNA genome) define a quasi-dodecahedral cage that line a substantial part of the capsid interior surface. The RNA duplexes establish a complex network of non-covalent interactions with pockets in the capsid inner wall, including coulombic interactions with a cluster of basic amino acid residues that surround each RNA duplex. A direct comparison was made between the cryo-EM structure of RNA-filled virions and that of RNA-free (empty) capsids that resulted from genome release from a small fraction of viruses. The comparison reveals that some specific residues involved in capsid-duplex RNA interactions in the virion undergo remarkable conformational rearrangements upon RNA release from the capsid. RNA release is also associated with the asynchronous opening of channels at the 30 two-fold axes. The results provide further insights into the molecular mechanisms leading to assembly of rhinovirus particles and their genome uncoating during infection. They may also contribute to development of novel antiviral strategies aimed at interfering with viral capsid-genome interactions during the infectious cycle.

Novel virulence determinants in VP1 regulate the assembly of enterovirus-A71.

EV-A71 causes hand, foot, and mouth disease in children. In this study, we discovered three highly conserved residues at positions 75, 78, and 88 of the capsid protein VP1 as the potential virulence determinants of EV-A71, which can influence viral replication by regulating the assembly of EV-A71. Mechanistic studies revealed that VP1-T75A could affect the maturation cleavage of the VP0 precursor, resulting in deficiencies in binding to the receptor SCARB2, viral attachment, internalization, and even uncoating. For the mutants of T78A and G88A, more noninfectious empty particles were produced during viral assembly. The discovery of these novel determinants of EV-A71 virulence will promote the study of the pathogenesis of enteroviruses.

Positivity Status and Molecular Characterization of Porcine Parvoviruses 1 Through 8 (PPV1-PPV8) from Slaughtered Pigs in China

Porcine parvoviruses one through eight (PPV1-PPV8) are prevalent in Chinese swine herds. However, the infection status of all these PPVs in slaughtered pigs is still unclarified. In this study, we detected PPV1-PPV8 in 353 tissue samples collected from slaughtered pigs from six regions of China in 2023. At least one species of PPV was detected in 79.32% of the samples (280 out of 353). Six PPV species were detected, except for PPV4 and PPV8, in slaughtered pigs, within which PPV3 (49.86%), PPV2 (42.49%), and PPV7 (42.21%) were predominant, followed by PPV1 (13.31%), PPV6 (13.31%), and PPV5 (8.22%). Noticeably, co-infection was frequently detected, with 67.50% of PPV-positive samples (189 out of 280) co-infecting with two to six PPVs. In addition, one representative genome for each detected PPV was determined. Multiple sequence alignment determined a large number of substitutions in capsid proteins of PPVs. Genome-based phylogenetic analysis confirmed the PCR detection results. Recombination detection identified two potential recombinants (PPV2 GDCZ2023-2088 strain and PPV3 HLJSYS2023-1654 strain) in slaughtered pigs. Overall, this study provides new insights into the prevalence and evolution of PPVs, particularly in slaughtered pigs in China.

Molecular characterization of a novel partitivirus with four segments isolated from Fusarium solani, the causal agent of citrus root rot.

We report here the identification of a dsRNA virus, obtained from Fusarium solani strain Newher-7, tentatively named F. solani partitivirus 3 (FsPV3). It consists of four dsRNA segments (dsRNA1-4) with lengths of 1961, 1900, 1830 and 1830 bp, respectively. Sequence analysis showed that dsRNA1 encodes an RNA-dependent RNA polymerase (RdRp), dsRNA2 encodes a capsid protein (CP), dsRNA3 encodes a hypothetical protein of unknown function and dsRNA4 encodes two hypothetical proteins of unknown function. Amino acid sequence comparisons showed that the RdRp of FsPV3 is most similar to that of Hulunbuir Parti tick virus 1. In contrast, the CP of FsPV3, as well as the hypothetical protein encoded by ORF3 of dsRNA3, was most similar to cognate proteins encoded by Colletotrichum-associated partitivirus 2. However, the two hypothetical proteins encoded by dsRNA4 showed no significant similarity to the available sequences in the National Center for Biotechnology Information database and encoded no apparent conserved domains. Phylogenetic analysis of the RdRp and CP showed that FsPV3 clustered together with other species in the genus Alphapartitivirus. Given that proteins encoded by FsPV3 are not sufficiently highly homologous to a single known virus and that it encodes two novel proteins, we suggest that FsPV3 should be regarded as a new member of the genus Alphapartitivirus in the family Partitiviridae. This is the first report of FsPV3 infecting F. solani.

IMMU-11. GUARDIANS OF INNATE IMMUNE ACTIVATION: CRUCIAL ROLES OF NONO AND CGAMP IN GLIOMA VIROTHERAPY

Abstract Despite aggressive therapeutic interventions, glioblastoma patients face a median survival of seven months after tumor recurrence. Alarmingly, there has been no improvement to the standard of care for two decades, and patients still receive toxic doses of radiation and chemotherapy, rendering many unable to perform daily functions. An emerging approach, oncolytic virotherapy (OV) using Delta-24-RGD, is gaining traction due to recent clinical trials (NCT00805376, NCT03178032, and NCT02798406) exhibiting robust responses in subsets of patients. While these studies demonstrated the therapeutic potential of OV, findings also indicate the early clearance of the virus, hindering the establishment of an effective anti-tumor immune response in most patients. We propose that mitigating the innate immune response against the therapeutic virus should result in improved intratumoral persistence, increasing the window of opportunity for developing an anti-tumor immune response. RNA-sequencing identified the non-POU domain containing octamer-binding (NONO) pathway as highly upregulated in syngenic glioma models and further amplified by OV treatment. In-vitro RNA sequencing and comparative analysis complemented these results to define a unique transcriptomic profile induced by adenovirus infection. LC-MS/MS identified host cGAS and adenoviral capsid proteins as candidate binding partners of NONO, which were validated using co-immunoprecipitation. Although the type I interferon cluster is deleted in most gliomas, tumor cells have a profound influence on their microenvironment through the secretion of the second messenger cGAMP. We show that NONO is required for cGAMP production, providing a mechanism to modulate antiviral responses in the tumor microenvironment during OV. Our findings underscore the significance of cGAMP shed from tumor cells in response to OV, and how NONO interacts with cGAS in the nucleus to sensor adenovirus infection. These findings uncover novel innate immunity mechanisms in gliomas and will inform the design of more efficacious oncolytic adenoviruses for glioma therapy.

In vitro characteristics of purified recombinant hepatitis C virus core protein

In our previous study, we established a method for purifying bacterially expressed HCV core 1–164 under non-denaturing conditions. In the present study, we elucidated the characteristics of the purified core. The purified HCV core exhibited a notable affinity for HCV RNA, with a Kd of 3 nM, as determined by a filter binding assay. Electron microscopy analysis revealed that the purified HCV core self-assembled with RNA into spherical structures approximately 50 nm in diameter. Additionally, we demonstrated the direct binding of the purified HCV core to the purified endoplasmic reticulum (ER). Moreover, lipid strip assays revealed specific binding of the purified HCV core to specific phospholipids, suggesting that the core plays a role in specific ER membrane domains. These studies reveal the biochemical characteristics of the HCV core that significantly advance our understanding of its role as a capsid protein in the viral lifecycle and pathogenesis.

Comprehensive Enteroviral Serology Links Infection and Anti-Melanoma Differentiation-Associated Protein 5 Dermatomyositis.

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous, systemic autoimmune diseases characterized by specific clinical features and, frequently, skeletal muscle inflammation. Specific subtypes of IIMs can be characterized by myositis-specific autoantibodies and are associated with distinct clinical phenotypes. Here, we focus on anti-melanoma differentiation-associated protein 5 (MDA5)-positive myositis and anti-signal recognition particle (SRP)-positive myositis, both of which exhibit seasonality but lack known environmental triggers. We employed Phage ImmunoPrecipitation Sequencing to profile serum antibodies against the human proteome, the human virome, and a comprehensive enterovirus library. We analyzed sera from 57 patients with anti-MDA5 autoantibodies and 57 patients with anti-SRP autoantibodies, as well as 57 healthy controls. All groups were matched for age, sex, and race. Our autoantibody profiling results define specific immunogenic regions within the MDA5 and SRP autoantigens. We also discovered that in MDA5 sera, versus SRP sera, there was an elevated antibody response to the viral capsid protein 1 (VP1) of enterovirus B, which was accompanied by a decreased antibody response to rhinovirus A. Considering the role of MDA5 as a sensor of picornaviral infections and a mediator of inflammatory signaling, our data suggest a novel etiologic link between enterovirus infection and anti-MDA5 dermatomyositis.

Determinants in the HTLV-1 Capsid Major Homology Region that are Critical for Virus Particle Assembly

The Gag protein of retroviruses is the primary driver of virus particle assembly. Particle morphologies among retroviral genera are distinct, with intriguing differences observed relative to HIV-1, particularly that of human T-cell leukemia virus type 1 (HTLV-1). In contrast to HIV-1 and other retroviruses where the capsid (CA) carboxy-terminal domain (CTD) possesses the key amino acid determinants involved in driving Gag-Gag interactions, we have previously demonstrated that the amino-terminal domain (NTD) encodes the key residues crucial for Gag multimerization and immature particle production. Here in this study, we sought to thoroughly interrogate the conserved HTLV-1 major homology region (MHR) of the CACTD to determine whether this region harbors residues important for particle assembly. In particular, site-directed mutagenesis of the HTLV-1 MHR was conducted, and mutants were analyzed for their ability to impact Gag subcellular distribution, particle production and morphology, as well as the CA-CA assembly kinetics. Several key residues (i.e., Q138, E142, Y144, F147 and R150), were found to significantly impact Gag multimerization and particle assembly. Taken together, these observations imply that while the HTLV-1 CANTD acts as the major region involved in CA-CA interactions, residues in the MHR can impact Gag multimerization, particle assembly and morphology, and likely play an important role in the conformation the CACTD that is required for CA-CA interactions.

EIF2Bβ confers resistance to Turnip mosaic virus by recruiting ALKBH9B to modify viral RNA methylation.

Eukaryotic translation initiation factors (eIFs) are the primary targets for overcoming RNA virus resistance in plants. In a previous study, we mapped a BjeIF2Bβ from Brassica juncea representing a new class of plant virus resistance genes associated with resistance to Turnip mosaic virus (TuMV). However, the mechanism underlying eIF2Bβ-mediated virus resistance remains unclear. In this study, we discovered that the natural variation of BjeIF2Bβ in the allopolyploid B. juncea was inherited from one of its ancestors, B. rapa. By editing of eIF2Bβ, we were able to confer resistance to TuMV in B. juncea and in its sister species of B. napus. Additionally, we identified an N6-methyladenosine (m6A) demethylation factor, BjALKBH9B, for interaction with BjeIF2Bβ, where BjALKBH9B co-localized with both BjeIF2Bβ and TuMV. Furthermore, BjeIF2Bβ recruits BjALKBH9B to modify the m6A status of TuMV viral coat protein RNA, which lacks the ALKB homologue in its genomic RNA, thereby affecting viral infection. Our findings have applications for improving virus resistance in the Brassicaceae family through natural variation or genome editing of the eIF2Bβ. Moreover, we uncovered a non-canonical translational control of viral mRNA in the host plant.

Enterovirus Antibodies: Friends and Foes.

Enteroviruses (EV) initiate replication by binding to their cellular receptors, leading to the uncoating and release of the viral genome into the cytosol of the host cell. Neutralising antibodies (NAbs) binding to epitopes on enteroviral capsid proteins can inhibit this infectious process through several mechanisms of neutralisation in vitro. Fc-mediated antibody effector functions such as antibody-dependent cell-mediated cytotoxicity and antibody-dependent cellular phagocytosis have also been described for some EV. However, antibody binding to virions does not always result in viral neutralisation. Non-neutralising antibodies, or sub-neutralising concentrations of antibodies, can enhance infection of viruses, leading to more severe pathologies. This phenomenon, known as antibody-dependent enhancement (ADE) of infection, has been described in vitro and/or in vivo for EV including poliovirus, coxsackievirus B and EV-A71. It has been shown that ADE of EV infection is mediated by FcγRs expressed by monocytes, macrophages, B lymphocytes and granulocytes. Antibodies play a crucial role in the diagnosis and monitoring of infections. They are valuable markers that have been used to establish a link between enteroviral infection and chronic diseases such as type 1 diabetes. Monoclonal and polyclonal antibodies targeting enteroviral proteins have been developed and shown to be effective to prevent or combat EV infections in vitro and in vivo. In addition, vaccines are under development, and clinical trials of vaccines are underway or have been completed, providing hope for the prevention of diseases due to EV. However, the ADE of the infection should be considered in the development of anti-EV antibodies or safe vaccines.

Molecular Analysis of Coxsackievirus B2 Associated With Severe Symptoms of the Central Nervous System.

Coxsackievirus B2 (CVB2) is a member of the enterovirus group known to induce a spectrum of illnesses, from mild to severe. In the summer of 2022, an unusual outbreak of enteroviral central nervous system (CNS) infections occurred that was attributed to CVB2. Cerebrospinal fluid (CSF) samples collected from patients in 2015-2022 were tested for enterovirus via RT-PCR, followed by Sanger sequencing for positive cases. CVB2 samples were further sequenced in the P1 region using NGS. A total of 30 CSF samples were identified as CVB2, with 60% of these cases occurring between June and August 2022. The 2022 CVB2 variants were associated with severe clinical symptoms, including encephalitis (50%) and ataxia (27.8%). Samples from 2015 to 2020 were also included due to the absence of these symptoms. Phylogenetic analysis revealed that CVB2 strains from 2019 to 2020 were also distinct from those obtained in 2022. Amino acid analysis of the capsid proteins VP1, VP2, and VP3 identified three unique substitutions with potential antigenic significance in the 2022 variant: S67A in VP2, and T93A and E274D in VP1. These substitutions were not present in earlier strains or reported in the literature, suggesting they may influence the virus's virulence. The clinical observations from this study highlight new patterns of CVB2 infection in the CNS that had not been previously observed. Additionally, it identifies unique genetic changes in the 2022 CVB2 variant that may account for the increased virulence seen in the 2022 outbreak. However, further analysis is required to validate this assumption.

Human parvovirus B19 virus-like particle formation in Nicotiana benthamiana

There has been a surge in the interest to utilize plants as hosts for producing vaccine antigens. In this study, we demonstrated the successful expression of the human parvovirus B19 (B19V) capsid protein (VP2) in Nicotiana benthamiana cells. The B19V VP1 and VP2 genes were cloned under the control of estrogen-inducible promoters and transiently expressed in N. benthamiana leaves using the agroinfiltration method. The addition of estrogen significantly boosted the expression of VP2. Furthermore, codon optimization of the VP2 sequence resulted in over a 30-fold increase in its expression compared with that of the wild-type. Analysis of negatively stained samples by sucrose density gradient ultracentrifugation and electron microscopy revealed that the expressed VP2 proteins formed spherical particles with diameters of approximately 20 nm. Immunostaining analysis of protoplasts derived from VP2-expressing N. benthamiana leaves indicated that VP2 signals were predominantly localized in the cytoplasm. These findings strongly suggested that B19V VP2 assembles and formed virus-like particles (VLPs) within the cytoplasm of N. benthamiana cells, presenting a promising method for producing B19V VLPs in plant systems.

An updated phylogeography and population dynamics of porcine circovirus 2 genotypes: are they reaching an equilibrium?

Porcine circovirus 2 (PCV2) emerged more than three decades ago as one of the most impactful pathogens in the swine industry. Despite being a DNA virus, one of the hallmarks of PCV2 is its high evolutionary rate, which has led to the emergence of different genotypes, each exhibiting varying degrees of evolutionary success. Current knowledge suggests the occurrence of three main waves of genotype dominance, alternating over time (i.e., PCV2a, PCV2b, and PCV2d), alongside less prevalent genotypes. However, although PCV2d is currently the most common genotype nowadays, the others continue being circulating in the pig population. The present study reconsidered the epidemiological and evolutionary patterns of PCV2 genotypes using phylodynamic analyses, benefiting from an almost 10-fold increase in ORF2 sequence availability compared to previous studies. Additionally, a phylogeographic analysis was performed to investigate viral dispersal patterns and frequency, and the selective pressures acting on the capsid protein were estimated and compared among genotypes. While successive emergence of major genotypes was confirmed, this study extends previous findings by revealing subsequent prevalence fluctuations of PCV2a and PCV2b after their initial decline. This evolutionary process may represent an example of balancing selection, specifically negative frequency-dependent selection, where a genotype fitness diminishes as it becomes more common, and vice versa. Variations in genotype- or clade-specific immunity-affected by the local prevalence of viral groups-combined with the periodic introduction of strains that have independently evolved in different regions, may have led to fluctuations in the population dynamics of major genotypes over time. These fluctuations were associated with ongoing evolution and variations in the capsid amino acid profile. These findings have profound implications for future control strategies. Although PCV2d remains the most prevalent and widespread genotype, other genotypes should not be neglected. Control strategies should thus target the entire PCV2 population, with a focus on fostering broader and more cross-protective immunity.

Conserved residues of the immunosuppressive domain of MLV are essential for regulating the fusion-critical SU-TM disulfide bond.

The Env protein of murine leukemia virus (MLV) is the prototype of a large clade of retroviral fusogens, collectively known as gamma-type Envs. Gamma-type Envs are found in retroviruses and endogenous retroviruses (ERVs) representing a broad range of vertebrate hosts. All gamma-type Envs contain a highly conserved stretch of 26-residues in the transmembrane subunit (TM) comprising two motifs, a putative immunosuppressive domain (ISD) and a CX6CC motif. Extraordinary conservation of the ISD and its invariant association with the CX6CC suggests a fundamental contribution to Env function. To investigate ISD function, we characterized several mutants with single amino acid substitutions at conserved positions in the MLV ISD. A majority abolished infectivity, although we did not observe a corresponding loss in intrinsic ability to mediate membrane fusion. Ratios of the surface subunit (SU) to capsid protein (CA) in virions were diminished for a majority of the ISD mutants, while TM:CA ratios were similar to wild type. Specific loss of SU reflected premature isomerization of the labile disulfide bond that links SU and TM prior to fusion. Indeed, all non-infectious mutants displayed significantly lower disulfide stability than wild-type Env. These results reveal a role for ISD positions 2, 3, 4, 7, and 10 in regulating a late step in entry after fusion peptide insertion but prior to creation of the fusion pore. This implies that the ISD is part of a larger domain, comprising the ISD and CX6CC motifs, that is critical for the formation and regulation of the metastable, intersubunit disulfide bond.IMPORTANCEThe gamma-type Env is a prevalent viral fusogen, found within retroviruses and endogenous retroviruses across vertebrate species and in filoviruses such as Ebolavirus. The fusion mechanism of gamma-type Envs is unique from other Class I fusogens such as those of influenza A virus and HIV-1. Gamma-type Envs contain a hallmark feature known as the immunosuppressive domain (ISD) that has been the subject of some controversy in the literature surrounding its putative immunosuppressive effects. Despite the distinctive conservation of the ISD, little has been done to investigate the role of this region for the function of this widespread fusogen. Our work demonstrates the importance of the ISD for the function of gamma-type Envs in infection, particularly in regulating the intermediate steps of membrane fusion. Understanding the fusion mechanism of gamma-type Envs has broad implications for understanding the entry of extant viruses and aspects of host biology connected to co-opted endogenous gamma-type Envs.

In Silico Development of a Multi-Epitope Subunit Vaccine against Bluetongue Virus in Ovis aries Using Immunoinformatics

The bluetongue virus (BTV), transmitted by biting midges, poses a significant threat to livestock globally. This orbivirus induces bluetongue disease, leading to substantial economic losses in the agricultural sector. The current control measures have limitations, necessitating the development of novel, efficient vaccines. In this study, an immunoinformatics approach is employed to design a multi-epitope subunit vaccine for Ovis aries targeting six BTV serotypes. Focusing on the VP2 capsid protein, the vaccine incorporates B-cell, helper-T lymphocytes (HTL), and cytotoxic T-cell lymphocytes (CTL) epitopes. Molecular docking reveals stable interactions with TLR2 and TLR4 receptors, suggesting the stability of the complex, indicating the potential viability of the multi-epitope vaccine. The computational approach offers a rapid and tailored strategy for vaccine development, highlighting potential efficacy and safety against BTV outbreaks. This work contributes to understanding BTV and presents a promising avenue for effective control.

Characterization of cross-reactive, non-neutralizing monoclonal antibodies against a pandemic GII.4 norovirus variant.

To gain insights into the overall immune responses to human norovirus, we characterized non-neutralizing, cross-reactive monoclonal antibodies (mAbs) developed against a pandemic GII.4 norovirus. We determined the binding epitope of an antibody that exhibited cross-reactivity against all tested noroviruses, which makes it a useful tool for research and diagnostics. The epitope of two additional non-neutralizing mAbs was mapped to a less conserved region on the viral capsid protein, explaining their cross-reactivity patterns. Often overlooked, the role of non-neutralizing, cross-reactive mAbs merits further research to facilitate our understanding of immunity to norovirus infection and disease.