Rational design of AAVrh10-vectored ACE2 functional domain to broadly block the cell entry of SARS-CoV-2 variants.

The frequently emerging SARS-CoV-2 variants have weakened the effectiveness of existing COVID-19 vaccines and neutralizing antibody therapy. Nevertheless, the infections of SARS-CoV-2 variants still depend on angiotensin-converting enzyme 2 (ACE2) receptor-mediated cell entry, and thus the soluble human ACE2 (shACE2) is a potential decoy for broadly blocking SARS-CoV-2 variants. In this study, we firstly generated the recombinant AAVrh10-vectored shACE2 constructs, a kind of adeno-associated virus (AAV) serotype with pulmonary tissue tropism, and then validated its inhibition capacity against SARS-CoV-2 infection. To further optimize the minimized ACE2 functional domain candidates, a comprehensive analysis was performed to clarify the interactions between the ACE2 orthologs from various species and the receptor binding domain (RBD) of SARS-CoV-2 spike (S) protein. Based on the key interface amino acids, we designed a series of truncated ACE2 orthologs, and then assessed their potential affinity to bind to SARS-CoV-2 variants RBD in silico. Of note, we found that the 24-83aa fragment of dog ACE2 (dACE224-83) had a higher affinity to the RBD of SARS-CoV-2 variants than that of human ACE2. Importantly, AAVrh10-vectored shACE2 or dACE224-83 constructs exhibited a broadly blockage breadth against SARS-CoV-2 prototype and variants in vitro and ex vivo. Collectively, these data highlighted a promising therapeutic strategy against SARS-CoV-2 variants.

Strategies to Develop a Mucosa-Targeting Vaccine against Emerging Infectious Diseases.

Numerous pathogenic microbes, including viruses, bacteria, and fungi, usually infect the host through the mucosal surfaces of the respiratory tract, gastrointestinal tract, and reproductive tract. The mucosa is well known to provide the first line of host defense against pathogen entry by physical, chemical, biological, and immunological barriers, and therefore, mucosa-targeting vaccination is emerging as a promising strategy for conferring superior protection. However, there are still many challenges to be solved to develop an effective mucosal vaccine, such as poor adhesion to the mucosal surface, insufficient uptake to break through the mucus, and the difficulty in avoiding strong degradation through the gastrointestinal tract. Recently, increasing efforts to overcome these issues have been made, and we herein summarize the latest findings on these strategies to develop mucosa-targeting vaccines, including a novel needle-free mucosa-targeting route, the development of mucosa-targeting vectors, the administration of mucosal adjuvants, encapsulating vaccines into nanoparticle formulations, and antigen design to conjugate with mucosa-targeting ligands. Our work will highlight the importance of further developing mucosal vaccine technology to combat the frequent outbreaks of infectious diseases.

Killing Two Birds with One Stone by Administration of Soluble ACE2: A Promising Strategy to Treat Both Cardiovascular Diseases and SARS-CoV-2 Infection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells mainly by the angiotensin converting enzyme 2 (ACE2) receptor, which can recognize the spike (S) protein by its extracellular domain. Previously, recombinant soluble ACE2 (sACE2) has been clinically used as a therapeutic treatment for cardiovascular diseases. Recent data demonstrated that sACE2 can also be exploited as a decoy to effectively inhibit the cell entry of SARS-CoV-2, through blocking SARS-CoV-2 binding to membrane-anchored ACE2. In this study, we summarized the current findings on the optimized sACE2-based strategies as a therapeutic agent, including Fc fusion to prolong the half-life of sACE2, deep mutagenesis to create high-affinity decoys for SARS-CoV-2, or designing the truncated functional fragments to enhance its safety, among others. Considering that COVID-19 patients are often accompanied by manifestations of cardiovascular complications, we think that administration of sACE2 in COVID-19 patients may be a promising therapeutic strategy to simultaneously treat both cardiovascular diseases and SARS-CoV-2 infection. This review would provide insights for the development of novel therapeutic agents against the COVID-19 pandemic.

Broadly Antiviral Activities of TAP1 through Activating the TBK1-IRF3-Mediated Type I Interferon Production.

Deeply understanding the virus-host interaction is a prerequisite for developing effective anti-viral strategies. Traditionally, the transporter associated with antigen processing type 1 (TAP1) is critical for antigen presentation to regulate adaptive immunity. However, its role in controlling viral infections through modulating innate immune signaling is not yet fully understood. In the present study, we reported that TAP1, as a product of interferon-stimulated genes (ISGs), had broadly antiviral activity against various viruses such as herpes simplex virus 1 (HSV-1), adenoviruses (AdV), vesicular stomatitis virus (VSV), dengue virus (DENV), Zika virus (ZIKV), and influenza virus (PR8) etc. This antiviral activity by TAP1 was further confirmed by series of loss-of-function and gain-of-function experiments. Our further investigation revealed that TAP1 significantly promoted the interferon (IFN)-ß production through activating the TANK binding kinase-1 (TBK1) and the interferon regulatory factor 3 (IRF3) signaling transduction. Our work highlighted the broadly anti-viral function of TAP1 by modulating innate immunity, which is independent of its well-known function of antigen presentation. This study will provide insights into developing novel vaccination and immunotherapy strategies against emerging infectious diseases.

Safety of SARS-CoV-2 vaccines: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Various modalities of vaccines against coronavirus disease 2019 (COVID-19), based on different platforms and immunization procedures, have been successively approved for marketing worldwide. A comprehensive review for clinical trials assessing the safety of COVID-19 vaccines is urgently needed to make an accurate judgment for mass vaccination. MAIN TEXT: A systematic review and meta-analysis was conducted to determine the safety of COVID-19 vaccine candidates in randomized controlled trials (RCTs). Data search was performed in PubMed, Embase, Cochrane library, Scopus, Web of Science, and MedRxiv. Included articles were limited to RCTs on COVID-19 vaccines. A total of 73,633 subjects from 14 articles were included to compare the risks of adverse events following immunization (AEFI) after vaccinating different COVID-19 vaccines. Pooled risk ratios (RR) of total AEFI for inactivated vaccine, viral-vectored vaccine, and mRNA vaccine were 1.34 [95% confidence interval (CI) 1.11-1.61, P < 0.001], 1.65 (95% CI 1.31-2.07, P < 0.001), and 2.01 (95% CI 1.78-2.26, P < 0.001), respectively. No significant differences on local and systemic AEFI were found between the first dose and second dose. In addition, people aged ≤ 55 years were at significantly higher risk of AEFI than people aged ≥ 56 years, with a pooled RR of 1.25 (95% CI 1.15-1.35, P < 0.001). CONCLUSIONS: The safety and tolerance of current COVID-19 vaccine candidates are acceptable for mass vaccination, with inactivated COVID-19 vaccines candidates having the lowest reported AEFI. Long-term surveillance of vaccine safety is required, especially among elderly people with underlying medical conditions.

An online survey of the attitude and willingness of Chinese adults to receive COVID-19 vaccination.

Background: A safe and effective vaccine against COVID-19 has become a public health priority. However, little is known about the public willingness to accept a future COVID-19 vaccine in China. This study aimed to understand the willingness and determinants for the acceptance of a COVID-19 vaccine among Chinese adults.Methods: A cross-sectional survey using an online questionnaire was conducted in an adult population in China. Chi-square tests were used to identify differences for various intentions regarding COVID-19 vaccination. The t test was used to identify differences among vaccine hesitancy scores. Multivariable logistic regression was used to analyze the predicated factors associated with the willingness to receive a COVID-19 vaccine.Results: Of the 3195 eligible participants, 83.8% were willing to receive a COVID-19 vaccine, and 76.6% believed the vaccine would be beneficial to their health; however, 74.9% expressed concerns or a neutral attitude regarding its potential adverse effects. Of the participants, 76.5% preferred domestically manufactured vaccines and were more willing to be vaccinated than those who preferred imported vaccines. Multivariable logistic regression indicated that lack of confidence, complacency in regard to health, risk of the vaccine, and attention frequency were the main factors affecting the intention to receive a COVID-19 vaccine.Conclusion: Our study indicated that the respondents in China had a high willingness to accept a COVID-19 vaccine, but some participants also worried about its adverse effects. Information regarding the efficacy and safety of an upcoming COVID-19 vaccine should be disseminated to ensure its acceptance and coverage.