Co-display of diverse spike proteins on nanoparticles broadens sarbecovirus neutralizing antibody responses

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants poses continuous challenges in combating the virus. Here, we describe vaccination strategies to broaden SARS-CoV-2 and sarbecovirus immunity by combining spike proteins based on different viruses or viral strains displayed on two-component protein nanoparticles. First, we combined spike proteins based on ancestral and Beta SARS-CoV-2 strains to broaden SARS-CoV-2 immune responses. Inclusion of Beta spike improved neutralizing antibody responses against SARS-CoV-2 Beta, Gamma, and Omicron BA.1 and BA.4/5. A third vaccination with ancestral SARS-CoV-2 spike also improved cross-neutralizing antibody responses against SARS-CoV-2 variants, in particular against the Omicron sublineages. Second, we combined SARS-CoV and SARS-CoV-2 spike proteins to broaden sarbecovirus immune responses. Adding SARS-CoV spike to a SARS-CoV-2 spike vaccine improved neutralizing responses against SARS-CoV and SARS-like bat sarbecoviruses SHC014 and WIV1. These results should inform the development of broadly active SARS-CoV-2 and pan-sarbecovirus vaccines and highlight the versatility of two-component nanoparticles for displaying diverse antigens

Two-component spike nanoparticle vaccine protects macaques from SARS-CoV-2 infection

Brouwer et al. present preclinical evidence in support of a COVID-19 vaccine candidate, designed as a self-assembling two-component protein nanoparticle displaying multiple copies of the SARS-CoV-2 spike protein, which induces strong neutralizing antibody responses and protects from high-dose SARS-CoV-2 challenge.The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is continuing to disrupt personal lives, global healthcare systems, and economies. Hence, there is an urgent need for a vaccine that prevents viral infection, transmission, and disease. Here, we present a two-component protein-based nanoparticle vaccine that displays multiple copies of the SARS-CoV-2 spike protein. Immunization studies show that this vaccine induces potent neutralizing antibody responses in mice, rabbits, and cynomolgus macaques. The vaccine-induced immunity protects macaques against a high-dose challenge, resulting in strongly reduced viral infection and replication i

Two proteins, one model organism: On the functional characterization of Lkb1 and Ring1b in zebrafish

Het verlies van het eiwit Lkb1 in de zebravis leidt niet tot defecten aan de bekleding van de darmwand. Het eiwit is wel essentieel bij de aanpassing van de stofwisseling als een voedselbron wegvalt. Dit toont Yme van der Velden aan in zijn onderzoek. Hij bestudeerde de functie van twee eiwitten, Lkb1 en Ring1b, in zebravissen. Mutaties in het Lkb1-gen veroorzaakt bij mensen de zeldzame ziekte het Peutz-Jeghers syndroom, dat wordt gekenmerkt door pigmentvlekken op de lippen, darmpoliepen en een grote kans op kanker. Van der Velden bekeek het eiwit Ring1b in het tweede deel van zijn onderzoek. Wanneer muizen dit eiwit niet aanmaken, worden de embryo’s niet goed geïmplanteerd in de baarmoeder. Als zebravissen dit eiwit missen, verloopt de vroegste embryonale ontwikkeling vrij normaal. Toch treden er grote embryonale defecten op tijdens de verdere ontwikkeling. Zo leidt het gemis van Ring1b ertoe dat er geen borstvinnen, kraakbeen en bot worden gevormd. Ring1b blijkt essentieel voor de aanmaak van bepaalde groeifactoren die nodig zijn voor de ontwikkeling van borstvinnen

The polycomb group protein ring1b/rnf2 is specifically required for craniofacial development

Polycomb group (PcG) genes are chromatin modifiers that mediate epigenetic silencing of target genes. PcG-mediated epigenetic silencing is implicated in embryonic development, stem cell plasticity, cell fate maintenance, cellular differentiation and cancer. However, analysis of the roles of PcG proteins in maintaining differentiation programs during vertebrate embryogenesis has been hampered due to the early embryonic lethality of several PcG knock-outs in the mouse. Here, we show that zebrafish Ring1b/Rnf2, the single E3 ubiquitin ligase in the Polycomb Repressive Complex 1, critically regulates the developmental program of craniofacial cell lineages. Zebrafish ring1b mutants display a severe craniofacial phenotype, which includes an almost complete absence of all cranial cartilage, bone and musculature. We show that Cranial Neural Crest (CNC)-derived cartilage precursors migrate correctly into the pharyngeal arches, but fail to differentiate into chondrocytes. This phenotype is specific for cartilage precursors, since other neural crest-derived cell lineages, including glia, neurons and chromatophores, are formed normally in ring1b mutants. Our results therefore reveal a critical and specific role for Ring1b in promoting the differentiation of cranial neural crest cells into chondrocytes. The molecular mechanisms underlying the pathogenesis of craniofacial abnormalities, which are among the most common genetic birth defects in humans, remain poorly understood. The zebrafish ring1b mutant provides a molecular model for investigating these mechanisms and may lead to the discovery of new treatments or preventions of craniofacial abnormalitie

Loss of endochondral and dermal ossification in <i>ring1b</i> mutants.

<p>Ventral (A–D, E, F) and lateral (A’–D’, E’,) views of <i>in situ</i> hybridizations with riboprobes against the indicated genes in WT and <i>ring1b</i> mutants at 68–72 hpf. In WT embryos, <i>runx2a</i> and <i>runx2b</i> are expressed in hypertrophic pharyngeal arch-derived chondrocytes, as well as in the dermal ossification centers of the operculum, parasphenoid and cleithrum. Weak expression is detected in pharyngeal arches and the parasphenoid of <i>ring1b</i> mutants (B, B’, D, D’). At 72 hpf, <i>col10a1</i> is expressed in developing dermal bones in WT embryos, but not in <i>ring1b</i> mutants (E–F). cl: cleithrum; de: dentary; h: hyoid; m: mandibular; mx: maxilla; pa: pharyngeal arches; pq: palatoquadrate; ps: parasphenoid, op: operculum cl: the cleithrum. Numbers indicate the respective pharyngeal arches.</p

<i>Ring1b</i> mutants lack almost all head cartilage elements.

<p>Lateral view of WT and <i>ring1b</i> live embryos at 72 hpf (A, B). Alcian-Blue stained head cartilages of WT (C, E, G and H) and <i>ring1b</i> (D, F, H and J) mutants at the indicated developmental points, ventral views. The paired trabeculae have elongated and fused posteriorly in WT embryos at 56 hpf (E) and by 72 hpf the elaborate cartilagenous skeleton of the head has been established (I). In contrast, no cartilage is visible in <i>ring1b</i> mutants except for two minute cartilage deposits at 72 hpf <i>ring1b</i> mutants (J: arrowheads). ch: ceratohyal; ep: ethmoid plate; hys: hyosymplectic; m: Meckel’s cartilage; pc: parachordal, pq: palatoquadrate; tc: trabeculae.</p

Apoptosis is slightly increased in the pharyngeal arch of <i>ring1b</i> mutants.

<p>Lateral views of WT and <i>ring1b</i> embryos at 36 hpf stained for TUNEL. In WT embryos two small clusters of TUNEL-positive apoptotic cells were detected in the pharyngeal arch region just posterior to the eye (A, arrows). These clusters appear to contain more apoptotic cells in the <i>ring1b</i> mutants (B, arrows). The arrowhead indicates the otic vesicle (ov). WT embryos at 36 hpf contain few apoptotic cells in the trunk (C), whereas there is an increase in overall apoptosis particularly in the trunk and the tail in <i>ring1b</i> mutants (D, arrows).</p