Stabilizing the RSV F protein in its prefusion conformation is crucial for effective vaccine development but has remained a significant challenge. Traditional stabilization methods, such as disulfide bonds and cavity-filling mutations, have been labor-intensive and have often resulted in suboptimal expression levels. Here, we report the design of an RSV prefusion F (preF) antigen using a proline-scanning strategy, incorporating seven proline substitutions to achieve stabilization. The resulting variant, preF7P, is structurally and biochemically validated to maintain the correct prefusion state. PreF7P demonstrates superior immunogenicity with a 1.8-fold increase in neutralizing antibody titers when compared to DS-cav2, and provides protection from clinical disease against both RSV A and B strains in female murine and female cotton rat models. In clinical development, preF7P exhibits high expression levels (~10 g/L) in clinical-grade CHO cells. The clinical-grade vaccine elicits robust immunogenic responses across female mice, female SD rats, and both male and female cynomolgus macaques, significantly boosting RSV pre-infection neutralizing antibody titers, and providing sustained protection for at least six months in female mice. This proline-scanning strategy offers a streamlined approach for stabilizing class I fusion proteins, potentially accelerating the development of vaccines for other pathogens.

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes febrile illness and acute or chronic arthritis. Most therapeutics are still in the pre-clinical stage. In this study, we report the isolation of two neutralizing antibodies, C34 and C37, from a convalescent patient and investigate their mechanisms of action. Both C34 and C37 exhibit high neutralizing activities in vitro and demonstrate protective effects against CHIKV in a female mouse model. Our functional and structural studies reveal a mechanism that inhibits multiple stages of the virus infection cycle. Both antibodies bind with high affinity to an epitope spanning E2, E1, and the connecting β-strands, facilitating intra- and inter-virion crosslinking. Cryo-EM structures additionally identify a minor patch located beneath the E3 binding site on E2, which is allosterically exposed upon E3 dissociation during virus maturation. Functional and structural data further suggest that binding to the CHIKV receptor, Mxra8, is obstructed due to a clash between the antibodies and the stalk region of Mxra8. Our results highlight the potential of antibody-based therapeutics against CHIKV and elucidate the mechanisms of monoclonal antibody protection.

Dengue fever is a mosquito-borne disease prevalent in tropical and subtropical regions, with its prevalence expanding due to increased global travel. The dengue virus, the causative agent of dengue fever, often co-circulates in the form of four distinct serotypes. Cross-reactive antibodies generated during a primary infection pose a significant risk during secondary infections with different serotypes, and fully protective vaccines and antiviral drugs are yet to be developed. Over the past decade, advances in antibody technology have led to the isolation of numerous monoclonal antibodies against dengue virus, with their neutralizing epitopes elucidated through structure-based analyses. This review highlights the key epitopes associated with neutralizing antibodies against dengue virus and discusses their potential applications in vaccine design and therapeutic antibody development. This review helps systematically summarize the progress in dengue virus neutralizing antibody research, providing a theoretical foundation and technical guidance for the development of novel vaccines and antibody therapeutics.

Various vaccine technologies have been employed in the coronavirus disease 2019 (COVID-19) vaccines, including whole inactivated virus (WIV), recombinant protein, mRNA, and nanoparticle vaccines. To elucidate the cellular mechanisms underlying the immune responses elicited by different vaccines, we examined and compared antigen-specific B cell responses targeting the receptor-binding domain (RBD) of the viral spike protein. We found that the nanoparticle vaccine pathogen-like antigens-RBD (PLA-RBD) and the mRNA vaccine demonstrated superior immunogenicity compared with the WIV vaccine and the RBD-dimer, a recombinant protein vaccine. Interestingly, the WIV vaccine contains toll-like receptor ligands that enhance IgG2a/c class-switching. For the mRNA vaccine, although it induces robust germinal center responses and T follicular helper (Tfh) cells, it has limited ability to induce memory B cells and long-lived plasma cells. These results indicate that vaccine formats significantly influence both the quantity and quality of immune responses, providing valuable insights for the future development of vaccines.

In recent work, Mucker et al.1 demonstrated that mRNA-1769 outperforms modified vaccinia Ankara (MVA), which has been deployed against recent mpox virus (MPXV) outbreaks, in reducing clinical symptoms and controlling viral replication, highlighting its potential as a scalable, safe, and effective next-generation platform for orthopoxvirus vaccination.

Inspired by the highly effective and broad-spectrum antifungal activity of ergosterol biosynthesis inhibitions, a series of novel 1,2,4-triazole derivatives containing oxime ether moiety were constructed for screening the bioactivity against phytopathogenic fungi. The (Z)- and (E)-isomers of target compounds were successfully separated and identified by the spectroscopy and single crystal X-ray diffraction analyses. The bioassay results showed that the (Z)-isomers of target compounds possessed higher antifungal activity than the (E)-isomers. Strikingly, the compound (Z)-5o exhibited excellent antifungal activity against Rhizoctonia solani with the EC50 value of 0.41 μg/mL in vitro and preventive effect of 94.58

With continuous mutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the severe immune escape of Omicron sub-variants urges the development of next-generation broad-spectrum vaccines, especially as booster jabs after high-level vaccination coverage of inactivated vaccines in China and many other countries. Previously, we developed a coronavirus disease 2019 (COVID-19) protein subunit vaccine ZF2001® based on the tandem homo-prototype receptor-binding domain (RBD)-dimer of the SARS-CoV-2 spike protein. We upgraded the antigen into a hetero-chimeric prototype (PT)-Beta or Delta-BA.1 RBD-dimer to broaden the cross-protection efficacy and prove its efficiency with protein subunit and mRNA vaccine platforms. Herein, we further explored the hetero-chimeric RBD-dimer mRNA vaccines and evaluated their broad-spectrum activities as booster jabs following two doses of inactivated vaccine (IV) in mice. Our data demonstrated that the chimeric vaccines significantly boosted neutralizing antibody levels and specific T-cell responses against the variants, and PT-Beta was superior to Delta-BA.1 RBD as a booster in mice, shedding light on the antigen design for the next-generation COVID-19 vaccines.

Current unprecedented mpox outbreaks in non-endemic regions represent a global public health concern. Although two live-attenuated vaccinia virus (VACV)-based vaccines have been urgently approved for people at high risk for mpox, a safer and more effective vaccine that can be available for the general public is desperately needed. By utilizing a simplified manufacturing strategy of mixing DNA plasmids before transcription, we developed two multi-antigen mRNA vaccine candidates, which encode four (M1, A29, B6, A35, termed as Rmix4) or six (M1, H3, A29, E8, B6, A35, termed as Rmix6) mpox virus antigens. We demonstrated that those mpox multi-antigen mRNA vaccine candidates elicited similar potent cross-neutralizing immune responses against VACV, and compared to Rmix4, Rmix6 elicited significantly stronger cellular immune responses. Moreover, immunization with both vaccine candidates protected mice from the lethal VACV challenge. Investigation of B-cell receptor (BCR) repertoire elicited by mpox individual antigen demonstrated that the M1 antigen efficiently induced neutralizing antibody responses, and all neutralizing antibodies among the top 20 frequent antibodies appeared to target the same conformational epitope as 7D11, revealing potential vulnerability to viral immune evasion. Our findings suggest that Rmix4 and Rmix6 from a simplified manufacturing process are promising candidates to combat mpox.

BACKGROUND:Increasing severe morbidity and mortality by simultaneous or sequential infections with SARS-CoV-2 and influenza A viruses (IAV), especially in the elderly and obese patients, highlight the urgency of developing a combination vaccine against COVID-19 and influenza. METHODS:Self-assembling SARS-CoV-2 RBD-trimer and Influenza H1N1 HA1-trimer antigens were constructed, upon the stable fusion core in post-fusion conformation. Immunogenicity of SARS-CoV-2 RBD-trimer vaccine and H1N1 HA1-trimer antigens candidates were evaluated in mice. Protection efficacy of a combination vaccine candidate against SARS-CoV-2 and IAV challenge was identified using the K18-hACE2 mouse model. FINDINGS:Both the resultant RBD-trimer for SARS-CoV-2 and HA1-trimer for H1N1 influenza fully exposed receptor-binding motifs (RBM) or receptor-binding site (RBS). Two-dose RBD-trimer induced significantly higher binding and neutralizing antibody titers, and also a strong Th1/Th2 balanced cellular immune response in mice. Similarly, the HA1-trimer vaccine was confirmed to exhibit potent immunogenicity in mice. A combination vaccine candidate, composed of RBD-trimer and HA1-trimer, afforded high protection efficacy in mouse models against stringent lethal SARS-CoV-2 and homogenous H1N1 influenza co-infection, characterized by 100% survival rate. INTERPRETATION:Our results represent a proof of concept for a combined vaccine candidate based on trimerized receptor binding domain against co-epidemics of COVID-19 and influenza. FUNDING:This project was funded by the Strategic Priority Research Program of CAS (XDB29040201), the National Natural Science Foundation of China (81830050, 81901680, and 32070569) and China Postdoctoral Science Foundation (2021M703450).

BACKGROUND The ZF2001 vaccine, which contains a dimeric form of the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 and aluminum hydroxide as an adjuvant, was shown to be safe, with an acceptable side-effect profile, and immunogenic in adults in phase 1 and 2 clinical trials. METHODS We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to investigate the efficacy and confirm the safety of ZF2001. The trial was performed at 31 clinical centers across Uzbekistan, Indonesia, Pakistan, and Ecuador; an additional center in China was included in the safety analysis only. Adult participants (>= 18 years of age) were randomly assigned in a 1:1 ratio to receive a total of three 25-mu g doses (30 days apart) of ZF2001 or placebo. The primary end point was the occurrence of symptomatic coronavirus disease 2019 (Covid-19), as confirmed on polymerase-chain-reaction assay, at least 7 days after receipt of the third dose. A key secondary efficacy end point was the occurrence of severe-to-critical Covid-19 (including Covid-19-related death) at least 7 days after receipt of the third dose. RESULTS Between December 12, 2020, and December 15, 2021, a total of 28,873 participants received at least one dose of ZF2001 or placebo and were included in the safety analysis; 25,193 participants who had completed the three-dose regimen, for whom there were approximately 6 months of follow-up data, were included in the updated primary efficacy analysis that was conducted at the second data cutoff date of December 15, 2021. In the updated analysis, primary end-point cases were reported in 158 of 12,625 participants in the ZF2001 group and in 580 of 12,568 participants in the placebo group, for a vaccine efficacy of 75.7% (95% confidence interval [CI], 71.0 to 79.8). Severe-to-critical Covid-19 occurred in 6 participants in the ZF2001 group and in 43 in the placebo group, for a vaccine efficacy of 87.6% (95% CI, 70.6 to 95.7); Covid-19-related death occurred in 2 and 12 participants, respectively, for a vaccine efficacy of 86.5% (95% CI, 38.9 to 98.5). The incidence of adverse events and serious adverse events was balanced in the two groups, and there were no vaccine-related deaths. Most adverse reactions (98.5%) were of grade 1 or 2. CONCLUSIONS In a large cohort of adults, the ZF2001 vaccine was shown to be safe and effective against symptomatic and severe-to-critical Covid-19 for at least 6 months after full vaccination.

以新冠肺炎为代表的传染病对人类健康和经济发展造成重大威胁.疫情暴发时的应急科研攻关是开发抗击疫情有力武器的关键,而有机结合了平时研究和应急攻关为一体的传染病防控平台是抗击疫情的基础.新冠肺炎疫情暴发以来,高福院士团队基于长期的研究积累,利用平急一体传染病防控平台,在新冠病毒的基础研究和应用研究两方面取得了重要成果,鉴定出新冠病毒的受体,揭示了新冠病毒以及变异株的入侵机制,跨种传播能力,基于入侵机制的理论基础开发出国际上第一个获批临床使用的新冠病毒重组亚单位疫苗以及在美国等十余国紧急使用的新冠肺炎治疗性抗体药物,迅速开发靶向3CL蛋白酶药物以及靶向入侵的多肽抑制剂,为中国以及世界新冠肺炎疫情的防控做出了重大贡献.

The devastating economic and public health consequences caused by the COVID-19 pandemic have prompted outstanding efforts from the scientific community and pharmaceutical companies to develop antibody-based therapeutics against SARS-CoV-2. Those efforts are encouraging and fruitful. An unprecedentedly large number of monoclonal antibodies (mAbs) targeting a large spectrum of epitopes on the spike protein has been developed in the last two years. The development of structural biology, especially the cryo-EM technology, provides structural insights into the molecular neutralizing mechanisms of those mAbs. Moreover, neutralizing antibodies are essential in protecting host from infection. Therefore, understanding the antibody neutralizing mechanism is critical for optimizing effective antibody-based therapeutics and developing next-generation pan-coronavirus vaccines. This review summarizes the latest understanding of antibody neutralizing mechanisms against SARS-CoV-2 at the molecular and structural levels.

Since the palivizumab for respiratory syncytial virus was approved in 1998, therapeutic antibodies against infectious diseases have been widely used in clinical treatment. Since the outbreak of COVID-19, plenty of neutralizing antibodies were developed and transferred into clinical trials, holding enormous promise for the treatment of COVID-19 under the context of emergency use authorization. This review summarizes the clinical progress of these drugs, in order to provide a reference for the research and development of neutralizing antibody drugs for the future.

The yellow fever virus (YFV) is a life-threatening human pathogen. Owing to the lack of available therapeutics, non-vaccinated individuals are at risk. Here, we isolated eight human monoclonal antibodies that neutralize YFV infection. Five recognized overlapping epitopes and exhibited potent neutralizing activity. Two (YD6 and YD73) were ultra-potent and conferred complete protection against the lethal challenge of YFV as both prophylactics and therapeutics in a mouse model. Crystal structures revealed that YD6 engaged the YFV envelope protein in both pre- and post-fusion states, suggesting viral inhibition by a “double-lock” mechanism. The recognition determinants for YD6 and YD73 are clustered at the premembrane (prM)-binding site. Notably, antibodies targeting this site were present in minute traces in YFV-infected individuals but contributed significantly to neutralization, suggesting a vulnerable supersite of YFV. We provide two promising candidates for immunotherapy against YFV, and the supersite represents an ideal target for epitope-based vaccine design.

Since the first report on November 24, 2021, the Omicron SARS-CoV-2 variant is now overwhelmingly spreading across the world. Two SARS-CoV-2 inactivated vaccines (IAVs), one recombinant protein subunit vaccine (PRV), and one adenovirus-vectored vaccine (AdV) have been widely administrated in many countries including China to pursue herd immunity. Here we investigated cross-neutralizing activities in 341 human serum specimens elicited by full-course vaccinations with IAV, PRV and AdV, and by various vaccine boosters following prime IAV and AdV vaccinations. We found that all types of vaccines induced significantly lower neutralizing antibody titers against the Omicron variant than against the prototype strain. For prime vaccinations with IAV and AdV, heterologous boosters with AdV and PRV, respectively, elevated serum Omicron-neutralizing activities to the highest degrees. In a mouse model, we further demonstrated that among a series of variant-derived RBD-encoding mRNA vaccine boosters, it is only the Omicron booster that significantly enhanced Omicron neutralizing antibody titers compared with the prototype booster following a prime immunization with a prototype S-encoding mRNA vaccine candidate. In summary, our systematical investigations of various vaccine boosters inform potential booster administrations in the future to combat the Omicron variant.

The neutralizing antibody is a potential therapeutic for the ongoing COVID-19 pandemic. As an antiviral agent, numerous mAbs recognize the epitopes that overlap with ACE2-binding sites in the SARS-CoV-2-RBD. Some studies have shown that residual changes on the spike protein can significantly decrease the efficiency of neutralizing antibodies. To address this issue, a therapeutic cocktail could be an effective countermeasure. In the present study, we isolated a fully human neutralizing antibody, JS026, from a convalescent patient. The comparative analysis revealed that JS026 binding to SARS-CoV-2-RBD mainly located between epitopes for class 2 and class 3 mAbs as opposed to that of class 1 (etesevimab) antibodies. A cocktail of etesevimab and JS026 increased neutralizing efficacy against both wild-type SARS-CoV-2 and the recent emergence of Alpha, Beta, Gamma, and Delta variants. JS026 and the cocktail reduced virus titers in the infected lungs of hACE2 transgenic mice and relieved pathological changes. These findings would benefit antibody-based therapeutic countermeasures in the treatment of COVID-19.

A safe, efficacious and deployable vaccine is urgently needed to control COVID-19 pandemic. We report here the preclinical development of a COVID-19 vaccine candidate, ZF2001, which contains tandem-repeat dimeric receptor-binding domain (RBD) protein with alum-based adjuvant. We assessed vaccine immunogenicity and efficacy in both mice and non-human primates (NHPs). ZF2001 induced high levels of RBD-binding and SARS-CoV-2 neutralizing antibody in both mice and NHPs, and also elicited balanced TH1/TH2 cellular responses in NHPs. Two doses of ZF2001 protected Ad-hACE2-transduced mice against SARS-CoV-2 infection, as detected by reduced viral RNA and relieved lung injuries. In NHPs, vaccination of either 25 μg or 50 μg ZF2001 prevented infection with SARS-CoV-2 in lung, trachea and bronchi, with milder lung lesions. No evidence of disease enhancement is observed in both models. ZF2001 is being evaluated in the ongoing international multi-center Phase 3 trials (NCT04646590) and has been approved for emergency use in Uzbekistan.