Broad neutralizing antibody response of a monomeric spike-based SARS-CoV-2 bivalent vaccine against diverse variants.

severeacute respiratory syndrome coronavirus 2 (SARS-CoV-2) bivalent vaccines show potential against variants but lack a full understanding of the immunological mechanisms that drive broadly neutralizing antibodies (bnAbs). This study explored the immunogenicity of a bivalent vaccine in rhesus macaques, containing spike (S) proteins from the prototype (S) and chimeric S protein (S). The vaccine induced bnAbs against multiple variants, including challenging subvariants like EG.

Increased pathogenicity and transmissibility in hamsters of all age groups reveal an underestimated perniciousness of severe acute respiratory syndrome coronavirus 2 EG.1 variant.

The evolution and mutation of SARS-CoV-2 is elusive. However, the diverse pathogenicity and transmissibility of different SARS-CoV-2 Omicron/XBB variants are not well understood. We compared virological attributes of two XBB variants, XBB.

Universal STING Pathway-Activating Complexes Counteract Viral Immune Evasion and Boost Antiviral Responses.

Viruses have evolved multiple mechanisms to counteract the stimulator of the interferon genes (STING) pathway, resulting in the suppression of antiviral responses. Accordingly, in addition to developing STING agonist analogs with enhanced stability and deliverability, overcoming the defective STING function in virus-infected cells is essential for defense against viral infections. In this study, we developed STING pathway-activating complexes (SPAC) based on bioinspired vesicles that display and multimerize STING molecules with a specific affinity for agonist binding.

Novel vaccine strategies to induce respiratory mucosal immunity: advances and implications.

Rapid advances in vaccine technology are becoming increasingly important in tackling global health crises caused by respiratory virus infections. While traditional vaccines, primarily administered by intramuscular injection, have proven effective, they often fail to provide the broad upper respiratory tract mucosal immunity, which is urgently needed for first-line control of respiratory viral infections. Furthermore, traditional intramuscular vaccines may not adequately address the immune escape of emerging virus variants.

Combination of spatial transcriptomics analysis and retrospective study reveals liver infection of SARS-COV-2 is associated with clinical outcomes of COVID-19.

Background: Liver involvement is a common complication of coronavirus disease 2019 (COVID-19), especially in hospitalized patients. However, the underlying mechanisms involved are not fully understood.

Methods: Immunohistochemistry (IHC) staining of SARS-CoV-2 spike (S) and nucleocapsid (N) proteins was conducted on liver tissues from six patients with COVID-19.

Decisive reversal of lethal coronavirus disease 2019 in senescent hamster by synchronic antiviral and immunoregulatory intervention.

The poor prognosis observed in elderly individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a serious clinical burden and the underlying mechanism is unclear, which necessities detailed investigation of disease characteristics and research for efficient countermeasures. To simulate lethal coronavirus disease 2019 (COVID-19) in senescent human patients, 80-week-old male hamsters are intranasally inoculated with different doses of SARS-CoV-2 Omicron BA.5 variant.

A cryptic site in class 5 epitope of SARS-CoV-2 RBD maintains highly conservation across natural isolates.

The emergence of SARS-CoV-2 variants raises concerns about the efficacy of existing COVID-19 vaccines and therapeutics. Previously, we identified a conserved cryptic class 5 epitope of SARS-CoV-2 receptor binding domain (RBD) by two cross-neutralizing antibodies 7D6 and 6D6. Intriguingly, this site remains resistant to substantial mutations occurred in ever-changing SARS-CoV-2 subvariants.

Sex hormones in COVID-19 severity: The quest for evidence and influence mechanisms.

Studies have reported variable effects of sex hormones on serious diseases. Severe disease and mortality rates in COVID-19 show marked gender differences that may be related to sex hormones. Sex hormones regulate the expression of the viral receptors ACE2 and TMPRSS2, which affect the extent of viral infection and consequently cause variable outcomes.

Intranasal influenza-vectored COVID-19 vaccines confer broad protection against SARS-CoV-2 XBB variants in hamsters.

The XBB.1.5 subvariant has garnered significant attention due to its exceptional immune evasion and transmissibility.

Butyrate Protects against SARS-CoV-2-Induced Tissue Damage in Golden Hamsters.

Butyrate, produced by gut microbe during dietary fiber fermentation, has anti-inflammatory and antioxidant effects on chronic inflammation diseases, yet it remains to be explored whether butyrate has protective effects against viral infections. Here, we demonstrated that butyrate alleviated tissue injury in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected golden hamsters supplemented with butyrate before and during the infection. Butyrate-treated hamsters showed augmentation of type I interferon (IFN) response and activation of endothelial cells without exaggerated inflammation.

Intranasal influenza-vectored COVID-19 vaccine restrains the SARS-CoV-2 inflammatory response in hamsters.

The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants and "anatomical escape" characteristics threaten the effectiveness of current coronavirus disease 2019 (COVID-19) vaccines. There is an urgent need to understand the immunological mechanism of broad-spectrum respiratory tract protection to guide broader vaccines development. Here we investigate immune responses induced by an NS1-deleted influenza virus vectored intranasal COVID-19 vaccine (dNS1-RBD) which provides broad-spectrum protection against SARS-CoV-2 variants in hamsters.

Antiviral Nanobiologic Therapy Remodulates Innate Immune Responses to Highly Pathogenic Coronavirus.

Highly pathogenic coronavirus (CoV) infection induces a defective innate antiviral immune response coupled with the dysregulated release of proinflammatory cytokines and finally results in acute respiratory distress syndrome (ARDS). A timely and appropriate triggering of innate antiviral response is crucial to inhibit viral replication and prevent ARDS. However, current medical countermeasures can rarely meet this urgent demand.

A SARS-CoV-2-specific CAR-T-cell model identifies felodipine, fasudil, imatinib, and caspofungin as potential treatments for lethal COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced cytokine storm is closely associated with coronavirus disease 2019 (COVID-19) severity and lethality. However, drugs that are effective against inflammation to treat lethal COVID-19 are still urgently needed. Here, we constructed a SARS-CoV-2 spike protein-specific CAR, and human T cells infected with this CAR (SARS-CoV-2-S CAR-T) and stimulated with spike protein mimicked the T-cell responses seen in COVID-19 patients, causing cytokine storm and displaying a distinct memory, exhausted, and regulatory T-cell phenotype.

Transcriptomics confirm the establishment of a liver-immune dual-humanized mouse model after transplantation of a single type of human bone marrow mesenchymal stem cell.

Background And Aims: Human bone marrow mesenchymal stem cells (hBMSCs) are important for developing a dual-humanized mouse model to clarify disease pathogenesis. We aimed to elucidate the characteristics of hBMSC transdifferentiation into liver and immune cells.

Methods: A single type of hBMSCs was transplanted into immunodeficient Fah-/- Rag2-/- IL-2Rγc-/- SCID (FRGS) mice with fulminant hepatic failure (FHF).

A Heterologous Challenge Rescues the Attenuated Immunogenicity of SARS-CoV-2 Omicron BA.1 Variant in Syrian Hamster Model.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is becoming a dominant circulator and has several mutations in the spike glycoprotein, which may cause shifts of immunogenicity, so as to result in immune escape and breakthrough infection among the already infected or vaccinated populations. It is unclear whether infection with Omicron could generate adequate cross-variant protection. To investigate this possibility, we used Syrian hamsters as an animal model for infection of SARS-CoV-2.

Nasal irrigation efficiently attenuates SARS-CoV-2 Omicron infection, transmission and lung injury in the Syrian hamster model.

Recently, a new variant lineage of SARS-CoV-2, namely Omicron, became the dominant global circulating strain. The multiple antigenic mutations of Omicron largely decrease the efficiency of current vaccines and neutralizing antibodies, which highlights the need for more potent and reachable medical countermeasures. Here, we hypothesize that direct viral clearance by nasal irrigation might be a convenient and alternative option, and perform proof-of-concept experiments in the Syrian hamster model.

Lineage-mosaic and mutation-patched spike proteins for broad-spectrum COVID-19 vaccine.

SARS-CoV-2 spread in humans results in continuous emergence of new variants, highlighting the need for vaccines with broad-spectrum antigenic coverage. Using inter-lineage chimera and mutation-patch strategies, we engineered a recombinant monomeric spike variant (STFK1628x) that contains key regions and residues across multiple SAR-CoV-2 variants. STFK1628x demonstrated high immunogenicity and mutually complementary antigenicity to its prototypic form (STFK).

Infection, pathology and interferon treatment of the SARS-CoV-2 Omicron BA.1 variant in juvenile, adult and aged Syrian hamsters.

The new predominant circulating SARS-CoV-2 variant, Omicron, can robustly escape current vaccines and neutralizing antibodies. Although Omicron has been reported to have milder replication and disease manifestations than some earlier variants, its pathogenicity in different age groups has not been well elucidated. Here, we report that the SARS-CoV-2 Omicron BA.

The neutralizing breadth of antibodies targeting diverse conserved epitopes between SARS-CoV and SARS-CoV-2.

Antibody therapeutics for the treatment of COVID-19 have been highly successful. However, the recent emergence of the Omicron variant has posed a challenge, as it evades detection by most existing SARS-CoV-2 neutralizing antibodies (nAbs). Here, we successfully generated a panel of SARS-CoV-2/SARS-CoV cross-neutralizing antibodies by sequential immunization of the two pseudoviruses.

A live attenuated virus-based intranasal COVID-19 vaccine provides rapid, prolonged, and broad protection against SARS-CoV-2.

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 d after single-dose vaccination or 9 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight.

Three SARS-CoV-2 antibodies provide broad and synergistic neutralization against variants of concern, including Omicron.

The rapidly spreading Omicron variant is highly resistant to vaccines, convalescent sera, and neutralizing antibodies (nAbs), highlighting the urgent need for potent therapeutic nAbs. Here, a panel of human nAbs from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) convalescent patients show diverse neutralization against Omicron, of which XMA01 and XMA04 maintain nanomolar affinities and excellent neutralization (half maximal inhibitory concentration [IC50]: ∼20 ng/mL). nAb XMA09 shows weak but unattenuated neutralization against all variants of concern (VOCs) as well as SARS-CoV.

Cross-species tropism and antigenic landscapes of circulating SARS-CoV-2 variants.

Mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) may alter viral host tropism and affect the activities of neutralizing antibodies. Here, we investigated 153 RBD mutants and 11 globally circulating variants of concern (VOCs) and variants of interest (VOIs) (including Omicron) for their antigenic changes and cross-species tropism in cells expressing 18 ACE2 orthologs. Several RBD mutations strengthened viral infectivity in cells expressing ACE2 orthologs of non-human animals, particularly those less susceptible to the ancestral strain.