Multi-compartmental diversification of neutralizing antibody lineages dissected in SARS-CoV-2 spike-immunized macaques.

The continued evolution of SARS-CoV-2 underscores the need to understand qualitative aspects of the humoral immune response elicited by spike immunization. Here, we combine monoclonal antibody (mAb) isolation with deep B cell receptor (BCR) repertoire sequencing of rhesus macaques immunized with prefusion-stabilized spike glycoprotein. Longitudinal tracing of spike-sorted B cell lineages in multiple immune compartments demonstrates increasing somatic hypermutation and broad dissemination of vaccine-elicited B cells in draining and non-draining lymphoid compartments, including the bone marrow, spleen and, most notably, periaortic lymph nodes.

Structural basis of broad SARS-CoV-2 cross-neutralization by affinity-matured public antibodies.

Descendants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant now account for almost all SARS-CoV-2 infections. The Omicron variant and its sublineages have spike glycoproteins that are highly diverged from the pandemic founder and first-generation vaccine strain, resulting in significant evasion from monoclonal antibody therapeutics and vaccines. Understanding how commonly elicited antibodies can broaden to cross-neutralize escape variants is crucial.

Antigen receptor stimulation induces purifying selection against pathogenic mitochondrial tRNA mutations.

Pathogenic mutations in mitochondrial (mt) tRNA genes that compromise oxidative phosphorylation (OXPHOS) exhibit heteroplasmy and cause a range of multisyndromic conditions. Although mitochondrial disease patients are known to suffer from abnormal immune responses, how heteroplasmic mtDNA mutations affect the immune system at the molecular level is largely unknown. Here, in mice carrying pathogenic C5024T in mt-tRNAAla and in patients with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS) syndrome carrying A3243G in mt-tRNALeu, we found memory T and B cells to have lower pathogenic mtDNA mutation burdens than their antigen-inexperienced naive counterparts, including after vaccination.

High-throughput measurement of the content and properties of nano-sized bioparticles with single-particle profiler.

We introduce a method, single-particle profiler, that provides single-particle information on the content and biophysical properties of thousands of particles in the size range 5-200 nm. We use our single-particle profiler to measure the messenger RNA encapsulation efficiency of lipid nanoparticles, the viral binding efficiencies of different nanobodies, and the biophysical heterogeneity of liposomes, lipoproteins, exosomes and viruses.

Caprin-1 binding to the critical stress granule protein G3BP1 is influenced by pH.

G3BP is the central node within stress-induced protein-RNA interaction networks known as stress granules (SGs). The SG-associated proteins Caprin-1 and USP10 bind mutually exclusively to the NTF2 domain of G3BP1, promoting and inhibiting SG formation, respectively. Herein, we present the crystal structure of G3BP1-NTF2 in complex with a Caprin-1-derived short linear motif (SLiM).

At-home sampling to meet geographical challenges for serological assessment of SARS-CoV-2 exposure in a rural region of northern Sweden, March to May 2021: a retrospective cohort study.

BackgroundThe current SARS-CoV-2 pandemic has highlighted a need for easy and safe blood sampling in combination with accurate serological methodology. Venipuncture for testing is usually performed by trained staff at healthcare centres. Long travel distances to healthcare centres in rural regions may introduce a bias of testing towards relatively large communities with closer access.

A Multiparametric and High-Throughput Platform for Host-Virus Binding Screens.

Speed is key during infectious disease outbreaks. It is essential, for example, to identify critical host binding factors to pathogens as fast as possible. The complexity of host plasma membrane is often a limiting factor hindering fast and accurate determination of host binding factors as well as high-throughput screening for neutralizing antimicrobial drug targets.

SARS-CoV-2 spike HexaPro formulated in aluminium hydroxide and administered in an accelerated vaccination schedule partially protects Syrian Hamsters against viral challenge despite low neutralizing antibody responses.

SARS-CoV-2 continues to pose a threat to human health as new variants emerge and thus a diverse vaccine pipeline is needed. We evaluated SARS-CoV-2 HexaPro spike protein formulated in Alhydrogel (aluminium oxyhydroxide) in Syrian hamsters, using an accelerated two dose regimen (given 10 days apart) and a standard regimen (two doses given 21 days apart). Both regimens elicited spike- and RBD-specific IgG antibody responses of similar magnitude, but virus neutralization was low or undetectable.

Silver nanoparticles with excellent biocompatibility block pseudotyped SARS-CoV-2 in the presence of lung surfactant.

Silver (Ag) is known to possess antimicrobial properties which is commonly attributed to soluble Ag ions. Here, we showed that Ag nanoparticles (NPs) potently inhibited SARS-CoV-2 infection using two different pseudovirus neutralization assays. We also evaluated a set of Ag nanoparticles of different sizes with varying surface properties, including polyvinylpyrrolidone (PVP)-coated and poly (ethylene glycol) (PEG)-modified Ag nanoparticles, and found that only the bare (unmodified) nanoparticles were able to prevent virus infection.

Immunoglobulin germline gene polymorphisms influence the function of SARS-CoV-2 neutralizing antibodies.

The human immunoglobulin heavy-chain (IGH) locus is exceptionally polymorphic, with high levels of allelic and structural variation. Thus, germline IGH genotypes are personal, which may influence responses to infection and vaccination. For an improved understanding of inter-individual differences in antibody responses, we isolated SARS-CoV-2 spike-specific monoclonal antibodies from convalescent health care workers, focusing on the IGHV1-69 gene, which has the highest level of allelic variation of all IGHV genes.

Protection against SARS-CoV-2 transmission by a parenteral prime-Intranasal boost vaccine strategy.

Background: Licensed vaccines against SARS-CoV-2 effectively protect against severe disease, but display incomplete protection against virus transmission. Mucosal vaccines providing immune responses in the upper airways are one strategy to protect against transmission.

Methods: We administered Spike HexaPro trimer formulated in a cationic liposomal adjuvant as a parenteral (subcutaneous - s.

Nanobodies in the limelight: Multifunctional tools in the fight against viruses.

Antibodies are natural antivirals generated by the vertebrate immune system in response to viral infection or vaccination. Unsurprisingly, they are also key molecules in the virologist's molecular toolbox. With new developments in methods for protein engineering, protein functionalization and application, smaller antibody-derived fragments are moving in focus.

Multivariate mining of an alpaca immune repertoire identifies potent cross-neutralizing SARS-CoV-2 nanobodies.

Conventional approaches to isolate and characterize nanobodies are laborious. We combine phage display, multivariate enrichment, next-generation sequencing, and a streamlined screening strategy to identify numerous anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nanobodies. We characterize their potency and specificity using neutralization assays and hydrogen/deuterium exchange mass spectrometry (HDX-MS).

Probabilistic classification of anti-SARS-CoV-2 antibody responses improves seroprevalence estimates.

Objectives: Population-level measures of seropositivity are critical for understanding the epidemiology of an emerging pathogen, yet most antibody tests apply a strict cutoff for seropositivity that is not learnt in a data-driven manner, leading to uncertainty when classifying low-titer responses. To improve upon this, we evaluated cutoff-independent methods for their ability to assign likelihood of SARS-CoV-2 seropositivity to individual samples.

Methods: Using robust ELISAs based on SARS-CoV-2 spike (S) and the receptor-binding domain (RBD), we profiled antibody responses in a group of SARS-CoV-2 PCR+ individuals ( = 138).

Beta RBD boost broadens antibody-mediated protection against SARS-CoV-2 variants in animal models.

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) with resistance to neutralizing antibodies are threatening to undermine vaccine efficacy. Vaccination and infection have led to widespread humoral immunity against the pandemic founder (Wu-Hu-1). Against this background, it is critical to assess the outcomes of subsequent immunization with variant antigens.

Multianalyte serology in home-sampled blood enables an unbiased assessment of the immune response against SARS-CoV-2.

Serological testing is essential to curb the consequences of the COVID-19 pandemic. However, most assays are still limited to single analytes and samples collected within healthcare. Thus, we establish a multianalyte and multiplexed approach to reliably profile IgG and IgM levels against several versions of SARS-CoV-2 proteins (S, RBD, N) in home-sampled dried blood spots (DBS).

SARS-CoV-2 protein subunit vaccination of mice and rhesus macaques elicits potent and durable neutralizing antibody responses.

The outbreak and spread of SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) is a current global health emergency, and effective prophylactic vaccines are needed urgently. The spike glycoprotein of SARS-CoV-2 mediates entry into host cells, and thus is the target of neutralizing antibodies. Here, we show that adjuvanted protein immunization with soluble SARS-CoV-2 spike trimers, stabilized in prefusion conformation, results in potent antibody responses in mice and rhesus macaques, with neutralizing antibody titers exceeding those typically measured in SARS-CoV-2 seropositive humans by more than one order of magnitude.

DNA-launched RNA replicon vaccines induce potent anti-SARS-CoV-2 immune responses in mice.

The outbreak of the SARS-CoV-2 virus and its rapid spread into a global pandemic made the urgent development of scalable vaccines to prevent coronavirus disease (COVID-19) a global health and economic imperative. Here, we characterized and compared the immunogenicity of two alphavirus-based DNA-launched self-replicating (DREP) vaccine candidates encoding either SARS-CoV-2 spike glycoprotein (DREP-S) or a spike ectodomain trimer stabilized in prefusion conformation (DREP-S). We observed that the two DREP constructs were immunogenic in mice inducing both binding and neutralizing antibodies as well as T cell responses.

Structure-guided multivalent nanobodies block SARS-CoV-2 infection and suppress mutational escape.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread, with devastating consequences. For passive immunization efforts, nanobodies have size and cost advantages over conventional antibodies. In this study, we generated four neutralizing nanobodies that target the receptor binding domain of the SARS-CoV-2 spike protein.

Adjuvanted SARS-CoV-2 spike protein elicits neutralizing antibodies and CD4 T cell responses after a single immunization in mice.

Background: SARS-CoV-2 has caused a global pandemic, infecting millions of people. A safe, effective vaccine is urgently needed and remains a global health priority. Subunit vaccines are used successfully against other viruses when administered in the presence of an effective adjuvant.

Picomolar SARS-CoV-2 Neutralization Using Multi-Arm PEG Nanobody Constructs.

Multivalent antibody constructs have a broad range of clinical and biotechnological applications. Nanobodies are especially useful as components for multivalent constructs as they allow increased valency while maintaining a small molecule size. We here describe a novel, rapid method for the generation of bi- and multivalent nanobody constructs with oriented assembly by Cu-free strain promoted azide-alkyne click chemistry (SPAAC).

Selection, biophysical and structural analysis of synthetic nanobodies that effectively neutralize SARS-CoV-2.

The coronavirus SARS-CoV-2 is the cause of the ongoing COVID-19 pandemic. Therapeutic neutralizing antibodies constitute a key short-to-medium term approach to tackle COVID-19. However, traditional antibody production is hampered by long development times and costly production.

SARS-CoV-2 exposure, symptoms and seroprevalence in healthcare workers in Sweden.

SARS-CoV-2 may pose an occupational health risk to healthcare workers. Here, we report the seroprevalence of SARS-CoV-2 antibodies, self-reported symptoms and occupational exposure to SARS-CoV-2 among healthcare workers at a large acute care hospital in Sweden. The seroprevalence of IgG antibodies against SARS-CoV-2 was 19.