Biology subjects

Carnell, G. W.

Publications and source records attributed to Carnell, G. W..

12 recordsLinked to original sources

bioRxiv2026

Development of an ELISA-Based Pulldown Approach for Functional Analysis of Antigen-Specific Antibodies

The identification of antigen-specific neutralising antibodies is essential for vaccine development and therapeutic discovery, yet current methods either lack functional readouts or are impractical for polyclonal sera from large cohorts. Here, we describe an ELISA-based pulldown methodology that isolates functional antibodies from serum samples while preserving their neutralising activity for downstream applications. We optimised elution conditions using 3M MgCl2 in HEPES buffer, which effectively disrupts antibody-antigen interactions without dislodging immobilised antigen or impairing antibody function. The assay demonstrated 100% specificity and 77.78% sensitivity for detecting known positive samples. Compatibility with pseudotype neutralisation assays was established, with maximum tolerable MgCl2 concentrations defined for direct use without dialysis. As proof-of-concept, we applied the method to identify domain-specific neutralising antibodies against the influenza virus haemagglutinin, distinguishing head-targeting from stem-targeting responses in human sera. This methodology provides a scalable platform for dissecting functional antibody responses with epitope-level resolution. HighlightsO_LIAdapted ELISA pulldown isolates functional antigen-specific antibodies C_LIO_LI3M MgCl2 elution preserves antibody functionality C_LIO_LICompatible with Influenza pseudotype neutralisation assays C_LIO_LIAllows for the identification of region-specific antibodies C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/706726v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1ab9bforg.highwire.dtl.DTLVardef@98e20borg.highwire.dtl.DTLVardef@120687dorg.highwire.dtl.DTLVardef@abf267_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Serological evidence of SARS-CoV-2 infection in red and fallow deer in Great Britain.

SARS-CoV-2 is the viral agent of COVID-19 disease in humans and has been shown to infect a wide range of mammals, including white-tailed deer in North America and fallow deer in the Republic of Ireland. There are six species of deer in the UK which inhabit both urban and rural areas, providing a broad interface for human-deer interaction. Little is known if British deer species act as a reservoir for zoonotic spread of consequence to human health. Here, we report a high seroprevalence of SARS-CoV-2 neutralising antibodies in British deer, adding native red deer to the list of susceptible species. 62% of fallow and 25% of red deer sampled between 2024 and 2025 from one British deer park were positive for SARS-CoV-2 infection by serology. Data suggest that deer may function as permissive, reservoir-capable hosts and highlight the risks of anthroponosis and zoonosis from unregulated human-deer contact. While there is currently no evidence to suggest that these viruses are persisting within deer populations in Great Britain, the animal origins of SARS-CoV-2 highlight the importance of appropriate and limited interactions with wildlife, to minimise transmission risks and safeguard both animal and human health.

microbiology↗

bioRxiv2025

Immunogenicity and Efficacy of Digitally Immune Optimised H1N1 Vaccine Candidates in Swine and Murine Animal Models

Influenza A virus (IAV) zoonotic transmission and constant evolution in multiple species heightens the risk of emerging novel strains at the human-animal interface. Composite antigens including hemagglutinin (HA), neuraminidase (NA), and matrix-2 (M2) proteins were computationally designed to maximize the breadth of the immune response elicited to human seasonal, pandemic, and zoonotic H1N1 IAVs. Mouse hyperimmune serum raised against these antigens demonstrated broad H1 neutralization and N1 inhibition activity. To enhance immunogenicity, the antigens were combined as a single DNA expression construct (DVX-H1N1). Studies in the well-recognized swine model for human influenza demonstrated that DVX-H1N1 immunization induced broad, neutralizing antibody responses and markedly reduced nasal shedding of viral RNA following challenge with 1A.3.3.2 subclade strain A/swine/England/1353/2009 (H1N1). An effective immune response and reduction in virus shedding was observed in pigs immunized with a whole inactivated virus (WIV) vaccine homologous to the challenge strain but not with a human-origin seasonal WIV vaccine. Overall, we demonstrated broad immunogenicity and efficacy of the DVX-H1N1 vaccine candidate, benchmarked against relevant IAV H1N1 strains in vitro and in vivo in mice and pigs. IMPORTANCEThe zoonotic potential of swine-origin IAVs is a recognized global health threat. Vaccination remains the most effective intervention against influenza; protecting at the population level by preventing nasal shedding and transmission, but also in individuals by limiting clinical disease, particularly by reducing the severity of lung infection. The World Health Organization (WHO) spearheads biannual surveillance efforts to review evolving virus strains and vaccine antigens at Vaccine Candidate Meetings (VCM) to recommend strain updates for the human seasonal influenza vaccine and for pandemic preparedness purposes. However, the strain selection approach is complex and efficaciousness of seasonal influenza vaccines still varies significantly based on the accurate matching of the predicted strains in circulation with the manufactured vaccine antigens. This emphasizes the need for next-generation influenza vaccines that improve the breadth and longevity of immunity. We describe a computationally optimized DNA vaccine with broad immunogenicity and robust efficacy in the pig model.

immunology↗

bioRxiv2025

Covering All Bases: A Computational Method to Design Broad-spectrum T-cell-inducing Vaccines Applied to Betacoronaviruses

Antigenically diverse pathogens, such as coronaviruses, pose substantial threats to global health. This highlights the need for effective broad-spectrum vaccines that elicit robust immune responses in a large proportion of the human population against a wide array of pathogen variants. Here, we introduce Spectravax, an AI-enabled computational method to design broad-spectrum vaccines that account for genetic diversity in both the host and pathogen populations. Using Spectravax, we designed a nucleocapsid (N) antigen to elicit cross-reactive immune responses to viruses from the Sarbecovirus and Merbecovirus subgenera of Betacoronaviruses. In silico analyses demonstrated superior predicted host and pathogen coverage for Spectravax compared to wild-type sequences and existing computational designs. Experimental validation in mice supported these predictions: Spectravax N elicited robust immune responses to SARS-CoV, SARS-CoV-2, and MERS-CoV--the three coronaviruses responsible for major outbreaks in humans since 2002--while wild-type and existing computational designs elicited limited responses. Furthermore, we were able to identify the MERS-CoV N epitopes responsible for Spectravaxs cross-reactivity. Thus, we advance the rational design of broad-spectrum vaccines for pandemic preparedness.

bioinformatics↗

bioRxiv2024

Digitally immune optimised haemagglutinin with nanocage plug-and-display elicits broadly neutralising pan-H5 influenza subtype vaccine responses

The increasing global spread of the highly pathogenic avian influenza (HPAI) A/H5 viruses poses a serious public health threat. Circulating clade 2.3.4.4b viruses have demonstrated rapid transcontinental dissemination, extensive reassortment, epizootic spread and potential sustained mammal-to-mammal transmission, signifying a heightened risk of becoming a human pathogen of high consequence. A broadly protective, future-proof vaccine against multiple clades of H5 influenza is urgently needed for pandemic preparedness. Here, we combine two novel vaccine technologies to generate a Digitally Immune Optimised and Selected H5 antigen (DIOSvax-H5inter) displayed multivalently on the mi3 nanocage using the SpyTag003/SpyCatcher003 conjugation system. Mice immunised with DIOSvax-H5inter Homotypic Nanocages at low doses demonstrate potent, cross-clade neutralising antibody and T cell responses against diverse H5 strains. DIOSvax-H5inter Homotypic Nanocages provide a scalable vaccine candidate with the potential for pan-H5 protection against drifted or newly emergent H5 strains. This World Health Organization preferred product characteristic is essential for prospective strategic stockpiling in the pre-pandemic phase.

immunology↗

bioRxiv2022

The SARS-CoV-2 protein ORF3c is a mitochondrial modulator of innate immunity

The SARS-CoV-2 genome encodes a multitude of accessory proteins. Using comparative genomic approaches, an additional accessory protein, ORF3c, has been predicted to be encoded within the ORF3a sgmRNA. Expression of ORF3c during infection has been confirmed independently by ribosome profiling. Despite ORF3c also being present in the 2002-2003 SARS-CoV, its function has remained unexplored. Here we show that ORF3c localises to mitochondria during infection, where it inhibits innate immunity by restricting IFN-{beta} production, but not NF-{kappa}B activation or JAK-STAT signalling downstream of type I IFN stimulation. We find that ORF3c acts after stimulation with cytoplasmic RNA helicases RIG-I or MDA5 or adaptor protein MAVS, but not after TRIF, TBK1 or phospho-IRF3 stimulation. ORF3c co-immunoprecipitates with the antiviral proteins MAVS and PGAM5 and induces MAVS cleavage by caspase-3. Together, these data provide insight into an uncharacterised mechanism of innate immune evasion by this important human pathogen.

microbiology↗

bioRxiv2021

Influenza A (N1-N9) and Influenza B (B/Vic and B/Yam) Neuraminidase Pseudotypes as Tools for Pandemic Preparedness and Improved Influenza Vaccine design

To better understand how inhibition of the influenza neuraminidase (NA) protein contributes to protection against influenza, and to investigate its breadth and cross-neutralizing activity, we have produced lentiviral vectors pseudotyped with an avian H11 hemagglutinin (HA) and the NA (N1-N9) of all influenza A and (B/Victoria and B/Yamagata) influenza B subtypes. These NA viral pseudotypes (PV) possess stable NA activity and can be utilized as target antigens in in vitro assays to assess vaccine immunogenicity. Employing these NA PV, we have developed an enzyme-linked lectin assay (pELLA) for routine serology to measure neuraminidase inhibition (NI) titers of reference antisera, monoclonal antibodies, and post-vaccination sera with various influenza antigens. We have also shown that pELLA is more sensitive than the commercially available NA-Fluor in detecting NA inhibition in these samples. Our studies may lead to establishing the protective NA titer that contributes to NA-based immunity. This will aid in the design of superior, longer lasting, and more broadly protective vaccines that can be employed together with HA-targeted vaccines in a pre-pandemic approach.

immunology↗

bioRxiv2021

The SARS-CoV-2 nucleocapsid protein associates with the replication organelles before viral assembly at the Golgi/ERGIC and lysosome-mediated egress

Despite being the target of extensive research efforts due to the COVID-19 pandemic, relatively little is known about the dynamics of SARS-CoV-2 replication within cells. We investigate and characterise the tightly orchestrated sequence of events during different stages of the infection cycle by visualising the spatiotemporal dynamics of the four structural proteins of SARS-CoV-2 at high resolution. The nucleoprotein is expressed first and accumulates around folded ER membranes in convoluted layers that connect to viral RNA replication foci. We find that of the three transmembrane proteins, the membrane protein appears at the Golgi apparatus/ERGIC before the spike and envelope proteins. Relocation of the lysosome marker LAMP1 towards the assembly compartment and its detection in transport vesicles of viral proteins confirm an important role of lysosomes in SARS-CoV-2 egress. These data provide new insights into the spatiotemporal regulation of SARS-CoV-2 assembly, and refine current understanding of SARS-CoV-2 replication.

microbiology↗

bioRxiv2021

Establishment of pan-Influenza A (H1-H18) and pan-Influenza B (pre-split, Vic/Yam) Pseudotype Libraries for efficient vaccine antigen selection

We have developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18, and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for detecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza serological and neutralization assays. We demonstrate its utility in detecting serum response to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further pre-clinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response.

immunology↗

bioRxiv2021

SARS-CoV-2 spike protein arrested in the closed state induces potent neutralizing responses

The majority of SARS-CoV-2 vaccines in use or in advanced clinical development are based on the viral spike protein (S) as their immunogen. S is present on virions as pre-fusion trimers in which the receptor binding domain (RBD) is stochastically open or closed. Neutralizing antibodies have been described that act against both open and closed conformations. The long-term success of vaccination strategies will depend upon inducing antibodies that provide long-lasting broad immunity against evolving, circulating SARS-CoV-2 strains, while avoiding the risk of antibody dependent enhancement as observed with other Coronavirus vaccines. Here we have assessed the results of immunization in a mouse model using an S protein trimer that is arrested in the closed state to prevent exposure of the receptor binding site and therefore interaction with the receptor. We compared this with a range of other modified S protein constructs, including representatives used in current vaccines. We found that all trimeric S proteins induce a long-lived, strongly neutralizing antibody response as well as T-cell responses. Notably, the protein binding properties of sera induced by the closed spike differed from those induced by standard S protein constructs. Closed S proteins induced more potent neutralising responses than expected based on the degree to which they inhibit interactions between the RBD and ACE2. These observations suggest that closed spikes recruit different, but equally potent, virus-inhibiting immune responses than open spikes, and that this is likely to include neutralizing antibodies against conformational epitopes present in the closed conformation. Together with their improved stability and storage properties we suggest that closed spikes may be a valuable component of refined, next-generation vaccines.

immunology↗

bioRxiv2021

SARS-CoV-2 spike downregulates tetherin to enhance viral spread

The antiviral restriction factor, tetherin, blocks the release of several different families of enveloped viruses, including the Coronaviridae. Tetherin is an interferon-induced protein that forms parallel homodimers between the host cell and viral particles, linking viruses to the surface of infected cells and inhibiting their release. We demonstrated that SARS-CoV-2 infection causes tetherin downregulation, and that tetherin depletion from cells enhances SARS-CoV-2 viral titres. We investigated the potential viral proteins involved in abrogating tetherin function and found that SARS- CoV-2 ORF3a reduces tetherin localisation within biosynthetic organelles via reduced retrograde recycling and increases tetherin localisation to late endocytic organelles. By removing tetherin from the Coronavirus budding compartments, ORF3a enhances virus release. We also found expression of Spike protein caused a reduction in cellular tetherin levels. Our results confirm that tetherin acts as a host restriction factor for SARS-CoV-2 and highlight the multiple distinct mechanisms by which SARS-CoV-2 subverts tetherin function. Author SummarySince it was identified in 2019, SARS-CoV-2 has displayed voracious transmissibility which has resulted in rapid spread of the virus and a global pandemic. SARS-CoV-2 is a member of the Coronaviridae family whose members are encapsulated by a host-derived protective membrane shell. Whilst the viral envelope may provide protection for the virus, it also provides an opportunity for the host cell to restrict the virus and stop it spreading. The anti-viral restriction factor, tetherin, acts to crosslink viruses to the surface of infected cells and prevent their spread to uninfected cells. Here, we demonstrate that SARS-CoV-2 undergoes viral restriction by tetherin, and that SARS-CoV-2 moves tetherin away from the site of Coronavirus budding to enhance its ability to escape and infect naive cells. Tetherin depletion from cells enhanced SARS-CoV-2 viral release and increased propagation of the virus. We found that the SARS-CoV-2 protein, ORF3a, redirects tetherin away from the biosynthetic organelles where tetherin would become incorporated to newly forming SARS-CoV-2 virions - and instead relocalises tetherin to late endocytic organelles. We also found that SARS-CoV-2 Spike downregulates tetherin. These two mechanisms, in addition to the well described antagonism of interferon and subsequent ISGs highlight the multiple mechanisms by which SARS-CoV-2 abrogates tetherin function. Our study provides new insights into how SARS-CoV-2 subverts human antiviral responses and escapes from infected cells.

cell biology↗

bioRxiv2017

Identification of an epitope of limited variability under strong immune selection in the haemagglutinin head domain of H1N1 influenza

Antigenic targets of influenza vaccination are currently seen to be polarised between (i) highly immunogenic (and protective) epitopes of high variability, and (ii) conserved epitopes of low immunogenicity. This requires vaccines directed against the variable sites to be continuously updated, with the only other alternative being seen as the artificial boosting of immunity to invariant epitopes of low natural efficacy. However, theoretical models suggest that the antigenic evolution of influenza is best explained by postulating the existence of highly immunogenic epitopes of limited variability. Here we report the identification of such an epitope of limited variability in the head domain of the H1 haemagglutinin protein. We show that the epitope mediates immunity to historical influenza strains not previously seen by a cohort of young children. Furthermore, vaccinating mice with these epitope conformations can induce immunity to all the human H1N1 influenza strains that have circulated since 1918. The identification of epitopes of limited variability offers a mechanism by which a universal influenza vaccine can be created; these vaccines would also have the potential to protect against newly emerging influenza strains.

epidemiology↗