A potent SARS-CoV-2 neutralising nanobody shows therapeutic efficacy in the Syrian golden hamster model of COVID-19.

SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration.

Quantification of SARS-CoV-2 neutralizing antibody by wild-type plaque reduction neutralization, microneutralization and pseudotyped virus neutralization assays.

Virus neutralization assays measure neutralizing antibodies in serum and plasma, and the plaque reduction neutralization test (PRNT) is considered the gold standard for measuring levels of these antibodies for many viral diseases. We have developed procedures for the standard PRNT, microneutralization assay (MNA) and pseudotyped virus neutralization assay (PNA) for severe acute respiratory syndrome coronavirus 2. The MNA offers advantages over the PRNT by reducing assay time, allowing increased throughput and reducing operator workload while remaining dependent upon the use of wild-type virus.

A COVID-19 vaccine candidate using SpyCatcher multimerization of the SARS-CoV-2 spike protein receptor-binding domain induces potent neutralising antibody responses.

There is need for effective and affordable vaccines against SARS-CoV-2 to tackle the ongoing pandemic. In this study, we describe a protein nanoparticle vaccine against SARS-CoV-2. The vaccine is based on the display of coronavirus spike glycoprotein receptor-binding domain (RBD) on a synthetic virus-like particle (VLP) platform, SpyCatcher003-mi3, using SpyTag/SpyCatcher technology.

Dose-dependent response to infection with SARS-CoV-2 in the ferret model and evidence of protective immunity.

There is a vital need for authentic COVID-19 animal models to enable the pre-clinical evaluation of candidate vaccines and therapeutics. Here we report a dose titration study of SARS-CoV-2 in the ferret model. After a high (5 × 10 pfu) and medium (5 × 10 pfu) dose of virus is delivered, intranasally, viral RNA shedding in the upper respiratory tract (URT) is observed in 6/6 animals, however, only 1/6 ferrets show similar signs after low dose (5 × 10 pfu) challenge.

Unfractionated heparin inhibits live wild type SARS-CoV-2 cell infectivity at therapeutically relevant concentrations.

Background And Purpose: Currently, there are no licensed vaccines and limited antivirals for the treatment of COVID-19. Heparin (delivered systemically) is currently used to treat anticoagulant anomalies in COVID-19 patients. Additionally, in the United Kingdom, Brazil and Australia, nebulised unfractionated heparin (UFH) is being trialled in COVID-19 patients as a potential treatment.

Author Correction: Neutralizing nanobodies bind SARS-CoV-2 spike RBD and block interaction with ACE2.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A cross-reactive human IgA monoclonal antibody blocks SARS-CoV-2 spike-ACE2 interaction.

COVID-19 caused by SARS-CoV-2 has become a global pandemic requiring the development of interventions for the prevention or treatment to curtail mortality and morbidity. No vaccine to boost mucosal immunity, or as a therapeutic, has yet been developed to SARS-CoV-2. In this study, we discover and characterize a cross-reactive human IgA monoclonal antibody, MAb362.

Neutralizing nanobodies bind SARS-CoV-2 spike RBD and block interaction with ACE2.

The SARS-CoV-2 virus is more transmissible than previous coronaviruses and causes a more serious illness than influenza. The SARS-CoV-2 receptor binding domain (RBD) of the spike protein binds to the human angiotensin-converting enzyme 2 (ACE2) receptor as a prelude to viral entry into the cell. Using a naive llama single-domain antibody library and PCR-based maturation, we have produced two closely related nanobodies, H11-D4 and H11-H4, that bind RBD (K of 39 and 12 nM, respectively) and block its interaction with ACE2.

Construction of FWPV Chimaeric MVA.

Construction of chimaeric MVA is a useful tool with which to study gene function of related viruses. The protocol given here describes MVA chimaeras containing genes from Fowlpox virus (FWPV), although this can be applied to DNA derived from other organisms. There are a number of steps required to make the chimaeric MVA: 1) Purification of viral particles; 2) Extraction of DNA from purified viral particles; 3) Assembly of linear recombination templates; 4) Transfection of linear recombination templates; 5) Selection of chimaeric MVA.

A novel vaccine against Crimean-Congo Haemorrhagic Fever protects 100% of animals against lethal challenge in a mouse model.

Crimean-Congo Haemorrhagic Fever (CCHF) is a severe tick-borne disease, endemic in many countries in Africa, the Middle East, Eastern Europe and Asia. Between 15-70% of reported cases are fatal. There is no approved vaccine available, and preclinical protection in vivo by an experimental vaccine has not been demonstrated previously.

Genetic screen of a mutant poxvirus library identifies an ankyrin repeat protein involved in blocking induction of avian type I interferon.

Mammalian poxviruses, including vaccinia virus (VACV), have evolved multiple mechanisms to evade the host type I interferon (IFN) responses at different levels, with viral proteins targeting IFN induction, signaling, and antiviral effector functions. Avian poxviruses (avipoxviruses), which have been developed as recombinant vaccine vectors for permissive (i.e.

Genetic screen of a library of chimeric poxviruses identifies an ankyrin repeat protein involved in resistance to the avian type I interferon response.

Viruses must be able to resist host innate responses, especially the type I interferon (IFN) response. They do so by preventing the induction or activity of IFN and/or by resisting the antiviral effectors that it induces. Poxviruses are no exception, with many mechanisms identified whereby mammalian poxviruses, notably, vaccinia virus (VACV), but also cowpox and myxoma viruses, are able to evade host IFN responses.

Murine interferon lambdas (type III interferons) exhibit potent antiviral activity in vivo in a poxvirus infection model.

Human interferon lambdas (IFN-lambdas) (type III IFNs) exhibit antiviral activity in vitro by binding to a receptor complex distinct from that used by type I and type II IFNs, and subsequent signalling through the Janus kinase signal transducers and activators of transcription (STAT) pathway. However, evidence for a function of type III IFNs during virus infection in vivo is lacking. Here, the expression of murine IFN-lambdas by recombinant vaccinia virus (VACV) is described and these proteins are shown to have potent antiviral activity in vivo.

Short communication: pitfalls of culturing C8166 cells in serum-free media.

Long-term culture of C8166 cells in serum-free media can result in changes in their level of expression of immunologically important cell surface makers and a loss of infectivity by HIV-1. We have now demonstrated that these phenotypic changes are due to an outgrowth of a very small number of contaminating cells of mouse origin. Our observations emphasize the importance of carefully recharacterizing any cells that have been adapted to grow in a serum-free culture media.