Biology subjects

Townsend, A. R.

Publications and source records attributed to Townsend, A. R..

9 recordsLinked to original sources

bioRxiv2025

Development of a Recombinant Single-Cycle Influenza Viral Vector as an Intranasal Vaccine against SARS-CoV-2 and SARS-like Betacoronaviruses

The COVID-19 pandemic has demonstrated the detrimental potential of zoonotic coronavirus transmission to human populations. Effective vaccines capable of eliciting immunity to SARS-CoV-2 have been pivotal in mitigating the spread of the virus. In this study, we describe the generation of a non-replicating pseudotyped influenza A virus (S-FLU), where the native haemagglutinin (HA) sequence is replaced with the coding sequence of either a membrane-anchored form (TM) or secretory form (Sec) of the receptor-binding domain (RBD) of the ancestral SARS-CoV-2 Wuhan (S-RBD Wuhan). We showed that both S-RBD-TM and S-RBD-Sec viruses can be generated via reverse genetics and grown to high titre. Intranasal immunisation in mice with S-RBD-TM elicits robust serum binding and neutralisation activity against SARS-CoV-2, superior to S-RBD-Sec. Furthermore, we demonstrate that a heterologous prime-boost immunisation regime in mice with S-RBD-TM Wuhan and S-RBD-TM BM48-31 (a distant Clade 3 SARS-like betacoronavirus (sarbecovirus)) increases antibody breadth against mismatched sarbecoviruses compared to homologous prime-boost with S-RBD-TM Wuhan. These results suggest that S-RBD-TM is a promising intranasal vaccine candidate against SARS-CoV-2 and may offer potential as a broadly protective sarbecovirus vaccine.

immunology↗

bioRxiv2024

Loop Grafting Improves Neuraminidase Protein Vaccine Production

Influenza virus neuraminidase is a crucial target for protective antibodies, yet the development of recombinant neuraminidase protein as a vaccine has been held back by instability and variable expression. We have taken a pragmatic approach to improving expression and stability of neuraminidase by grafting antigenic surface loops from low-expressing neuraminidase proteins onto the scaffold of high-expressing counterparts. The resulting hybrid proteins retained the antigenic properties of the loop donor while benefiting from the high-yield expression, stability, and tetrameric structure of the loop recipient. These hybrid proteins were recognised by a broad set of human monoclonal antibodies elicited by influenza infection or vaccination, with X-ray structures validating the accurate structural conformation of the grafted loops and the enzymatic cavity. Immunisation of mice with neuraminidase hybrids induced inhibitory antibodies to the loop donor and protected against lethal influenza challenge. This pragmatic technique offers a robust solution for improving the expression and stability of influenza neuraminidase proteins for vaccine development. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/617814v3_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@14d4b4eorg.highwire.dtl.DTLVardef@18af09aorg.highwire.dtl.DTLVardef@ba1982org.highwire.dtl.DTLVardef@1e0d143_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

A broadly-neutralizing antibody against Ebolavirus glycoprotein that potentiates the breadth and neutralization potency of other antibodies

Ebolavirus disease (EVD) is caused by multiple species of Ebolavirus. Monoclonal antibodies (mAbs) against the virus glycoprotein (GP) are the only class of therapeutic approved for treatment of EVD caused by Zaire ebolavirus (EBOV). Therefore, mAbs targeting multiple Ebolavirus species may represent the next generation of EVD therapeutics. Broadly reactive anti-GP mAbs were produced; among these, mAbs 11886 and 11883 were broadly neutralizing in vitro. A 3.0 [A] cryo-electron microscopy structure of EBOV GP bound to both mAbs shows that 11886 binds a novel epitope bridging the glycan cap (GC), 310 pocket and GP2 N-terminus, whereas 11883 binds the receptor binding region (RBR) and GC. In vitro, 11886 synergized with a range of mAbs with epitope specificities spanning the RBR/GC, including 11883. Notably, 11886 increased the breadth of neutralization by partner mAbs against different Ebolavirus species. These data provide a strategic route to design improved mAb-based next-generation EVD therapeutics.

immunology↗

bioRxiv2024

A locally administered single cycle influenza vaccine expressing a non-fusogenic stabilised haemagglutinin stimulates strong T-cell and neutralising antibody immunity

Current influenza vaccination approaches protect against specific viral strains, but do not consistently induce broad and long-lasting protection to the diversity of circulating influenza viruses. Single cycle viruses delivered to the respiratory tract may offer a promising solution as they safely express a diverse array of viral antigens by undergoing just one round of cell infection in their host and stimulate broadly protective resident memory T-cell responses in the lung. We have previously developed a vaccine candidate called S-FLU that is limited to a single cycle of infection by inactivation of the hemagglutinin signal sequence and induces a broadly cross-reactive T-cell response and antibodies to neuraminidase, but fails to induce neutralising antibodies to hemagglutinin after intranasal administration. This study describes the development of CLEARFLU, a derivative of S-FLU that is designed to add a neutralising antibody response to hemagglutinin. In contrast to S-FLU, which does not express a hemagglutinin molecule at the infected cell surface, CLEARFLU viruses express a stabilised non-fusogenic hemagglutinin. They are equally limited to a single cycle of infection, but induce a neutralising antibody response to the expressed hemagglutinin in addition to the cytotoxic T lymphocyte (CTL) responses to internal proteins and antibodies to neuraminidase induced by S-FLU. This represents a notable advantage as CLEARFLU viruses may provide sterile immunity against strain-matched challenge as well as non-sterile protection against a broad range of influenza viruses. ImportanceInfluenza is a serious public health concern, causing seasonal epidemics as well as pandemics in people. Influenza can also cause severe agricultural losses due to its circulation in farmed poultry and swine. A major challenge in the control of influenza is the diversity of circulating viruses. Developing vaccines which stimulate immunity to a wide array of influenza viruses is therefore important for protecting human and animal populations from disease and death. In this study, we describe an approach for developing influenza vaccines which trigger immune mechanisms shown to induce broad protection against a diversity of viruses, while also conserving the strong protection against specific strains observed in existing vaccines.

immunology↗

bioRxiv2023

Multiviral Quartet Nanocages Elicit Broad Anti-Coronavirus Responses for Proactive Vaccinology

Defending against future pandemics may require vaccine platforms that protect across a range of related pathogens. The presentation of multiple receptor-binding domains (RBDs) from evolutionarily-related viruses on a nanoparticle scaffold elicits a strong antibody response to conserved regions. Here we produce quartets of tandemly-linked RBDs from SARS-like betacoronaviruses coupled to the mi3 nanocage through a SpyTag/SpyCatcher spontaneous reaction. These Quartet Nanocages induce a high level of neutralizing antibodies against several different coronaviruses, including against viruses not represented on the vaccine. In animals primed with SARS-CoV-2 Spike, boost immunizations with Quartet Nanocages increased the strength and breadth of an otherwise narrow immune response. Quartet Nanocages are a strategy with potential to confer heterotypic protection against emergent zoonotic coronavirus pathogens and facilitate proactive pandemic protection. One Sentence SummaryA vaccine candidate with polyprotein antigens displayed on nanocages induces neutralizing antibodies to multiple SARS-like coronaviruses.

immunology↗

bioRxiv2022

Mosaic RBD nanoparticles protect against multiple sarbecovirus challenges in animal models

To combat future SARS-CoV-2 variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global health, we designed mosaic nanoparticles presenting randomly-arranged sarbecovirus spike receptor-binding domains (RBDs) to elicit antibodies against conserved/relatively-occluded, rather than variable/immunodominant/exposed, epitopes. We compared immune responses elicited by mosaic-8 (SARS-CoV-2 and seven animal sarbecoviruses) and homotypic (only SARS-CoV-2) RBD-nanoparticles in mice and macaques, observing stronger responses elicited by mosaic-8 to mismatched (not on nanoparticles) strains including SARS-CoV and animal sarbecoviruses. Mosaic-8 immunization showed equivalent neutralization of SARS-CoV-2 variants including Omicron and protected from SARS-CoV-2 and SARS-CoV challenges, whereas homotypic SARS-CoV-2 immunization protected only from SARS-CoV-2 challenge. Epitope mapping demonstrated increased targeting of conserved epitopes after mosaic-8 immunization. Together, these results suggest mosaic-8 RBD-nanoparticles could protect against SARS-CoV-2 variants and future sarbecovirus spillovers.

microbiology↗

bioRxiv2021

Low dose pig anti-influenza virus monoclonal antibodies reduce lung pathology but do not prevent virus shedding

We have established the pig, a large natural host animal for influenza, with many physiological similarities to humans, as a robust model for testing the therapeutic potential of monoclonal antibodies (mAbs). In this study we demonstrated that prophylactic intravenous administration of 15mg/kg of porcine mAb pb18, against the K160-163 site of the haemagglutinin, significantly reduced lung pathology and nasal virus shedding and eliminated virus from the lung of pigs following H1N1pdm09 challenge. When given at 1mg/kg, pb18 significantly reduced lung pathology and lung and BAL virus loads, but not nasal shedding. Similarly, when pb18 was given in combination with pb27, which recognised the K130 site, at 1mg/kg each, lung virus load and pathology were reduced, although without an apparent additive or synergistic effect. No evidence for mAb driven virus evolution was detected. These data indicate that intravenous administration of high doses was required to reduce nasal virus shedding, although this was inconsistent and seldom complete. In contrast the effect on lung pathology and lung virus load is consistent and is also seen at one log lower doses, strongly indicating that a lower dose might be sufficient to reduce severity of disease, but for prevention of transmission other measures would be needed.

immunology↗

bioRxiv2020

Recognition of Z-RNA by ADAR1 limits interferon responses

Nucleic acids are powerful triggers of innate immunity and can adopt the unusual Z-conformation. The p150 isoform of adenosine deaminase acting on RNA 1 (ADAR1) prevents aberrant interferon (IFN) induction and contains a Z-nucleic acid binding (Z) domain. We report that knock-in mice bearing two point mutations in the Z domain of ADAR1, which abolish binding to Z-form nucleic acids, spontaneously induced type I IFNs and IFN-stimulated genes (ISGs) in multiple organs. This included the lung where both stromal and haematopoietic cells displayed ISG induction in Adar1mZ/mZ mice. Concomitantly, Adar1mZ/mZ mice showed improved control of influenza A virus. The spontaneous IFN response in Adar1mZ/mZ mice required MAVS, implicating cytosolic RNA sensing. Finally, analysis of A-to-I changes revealed a specific requirement of ADAR1s Z domain in editing of a subset of RNAs. In summary, our results reveal that endogenous RNAs in Z-conformation have immunostimulatory potential that is curtailed by ADAR1.

immunology↗

bioRxiv2020

Protective porcine influenza virus-specific monoclonal antibodies recognize similar haemagglutinin epitopes as humans

Pigs are natural hosts for the same subtypes of influenza A viruses as humans and integrally involved in virus evolution with frequent interspecies transmissions in both directions. The emergence of the 2009 pandemic H1N1 virus illustrates the importance of pigs in evolution of zoonotic strains. Here we generated pig influenza-specific monoclonal antibodies (mAbs) from H1N1pdm09 infected pigs. The mAbs recognized the same two major immunodominant haemagglutinin (HA) epitopes targeted by humans, one of which is not recognized by post-infection ferret antisera that are commonly used to monitor virus evolution. Neutralizing activity of the pig mAbs was comparable to that of potent human anti-HA mAbs. Further, prophylactic administration of a selected porcine mAb to pigs abolished lung viral load and greatly reduced lung pathology but did not eliminate nasal shedding of virus after H1N1pdm09 challenge. Hence mAbs from pigs, which target HA can significantly reduce disease severity. These results, together with the comparable sizes of pigs and humans, indicate that the pig is a valuable model for understanding how best to apply mAbs as therapy in humans and for monitoring antigenic drift of influenza viruses in humans, thereby providing information highly relevant to making influenza vaccine recommendations.

immunology↗