Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.str.2023.12.013

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers in Cellular and Infection Microbiology  

INTRODUCTION: We examined the neutralizing antibody production efficiency of the second and third severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine doses (2nd- and 3rd-dose) and neutralizing activity on mutant strains, including, the Ancestral, Beta and Omicron strains using green fluorescent protein-carrying recombinant SARS-CoV-2, in living-donor liver transplantation (LDLT) recipients. METHODS: The patients who were administered vaccines other than Pfizer- BioNTechBNT162b2 and who had coronavirus disease 2019 in this study period were excluded. We enrolled 154 LDLT recipients and 50 healthy controls. RESULT: The median time were 21 days (between 1st and 2nd vaccination) and 244 days (between 2nd and 3rd vaccination). The median neutralizing antibody titer after 2nd-dose was lower in LDLT recipients than in controls (0.46 vs 1.00, P<0.0001). All controls had SARS-CoV-2 neutralizing antibodies, whereas 39 LDLT recipients (25.3%) had no neutralizing antibodies after 2nd-dose; age at vaccination, presence of ascites, multiple immunosuppressive treatments, and mycophenolate mofetil treatment were significant risk factors for nonresponder. The neutralizing activities of recipient sera were approximately 3-fold and 5-fold lower than those of control sera against the Ancestral and Beta strains, respectively. The median antibody titer after 3rd-dose was not significantly different between recipients and controls (1.02 vs 1.22, p=0.0758); only 5% recipients was non-responder. The neutralizing activity after third dose to Omicron strains were enhanced and had no significant difference between two groups. CONCLUSION: Only the 2nd-dose was not sufficiently effective in recipients; however, 3rd-dose had sufficient neutralizing activity against the mutant strain and was as effective as that in healthy controls.

DOI： 10.3389/fcimb.2023.1197349

Web of Science

Scopus

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Microbiology and Immunology  

Smoking is one of the risk factors most closely related to the severity of COVID-19. However, the relationship between smoking history and SARS-CoV-2 infectivity is unknown. In this study, we evaluated the ACE2 expression level in the lungs of current smokers, ex-smokers, and non-smokers. The ACE2 expression level of ex-smokers who smoked cigarettes until recently (cessation period shorter than 6 months) was higher than that of non-smokers and ex-smokers with a long history of non-smoking (cessation period longer than 6 months). We also showed that the efficiency of SARS-CoV-2 infection was enhanced in a manner dependent on the ACE2 expression level. Using RNA-seq analysis on the lungs of smokers, we identified that the expression of inflammatory signaling genes was correlated with ACE2 expression. Notably, with increasing duration of smoking cessation among ex-smokers, not only ACE2 expression level but also the expression levels of inflammatory signaling genes decreased. These results indicated that smoking enhances the expression levels of ACE2 and inflammatory signaling genes. Our data suggest that the efficiency of SARS-CoV-2 infection is enhanced by smoking-mediated upregulation of ACE2 expression level. This article is protected by copyright. All rights reserved.

DOI： 10.1111/1348-0421.13034

Web of Science

Scopus

PubMed

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Cold Spring Harbor Laboratory  

DOI： 10.1101/2022.02.22.481436

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

The emergence of a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, Omicron, is an urgent global health concern (ref.1). Our statistical modelling suggests that Omicron has spread more rapidly than the Delta variant in several countries including South Africa. Cell culture experiments show that Omicron is less fusogenic than Delta and an ancestral SARS-CoV-2 strain. Although the spike (S) protein of Delta is efficiently cleaved into two subunits, which facilitates cell-cell fusion2,3, Omicron S is less efficiently cleaved compared to Delta S and ancestral SARS-CoV-2 S. Furthermore, in a hamster model, Omicron shows decreased lung infectivity and is less pathogenic compared to Delta and ancestral SARS-CoV-2.

DOI： 10.1038/s41586-022-04462-1

PubMed

Language：English   Publisher：Nature Communications  

The global circulation of SARS-CoV-2 in human populations has driven the emergence of Omicron subvariants, which have become highly diversified through recombination. In late 2024, SARS-CoV-2 Omicron XEC variant emerged from the recombination of two JN.1 progeny, KS.1.1 and KP.3.3, and became predominant worldwide. Here, we investigate virological features of the XEC variant. Epidemic dynamics modeling suggests that spike substitutions in XEC mainly contribute to its increased viral fitness. Additionally, four licensed antivirals are effective against XEC. Although the fusogenicity of XEC spike is comparable to that of the JN.1 spike, the intrinsic pathogenicity of XEC in male hamsters is significantly higher than that of JN.1. Notably, we find that the nucleocapsid R204P mutation of XEC enhances inflammation through NF-κB activation. Recent studies suggest that the evolutionary potential of spike protein is reaching its limit. Indeed, our findings highlight the critical role of non-spike mutations in the future evolution of SARS-CoV-2.

DOI： 10.1038/s41467-025-67455-4

Web of Science

Scopus

PubMed

Language：English   Publisher：John Wiley & Sons Australia, Ltd  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Microbiology and Immunology  

Reverse genetics enables the generation of recombinant viruses; however, conventional approaches using full-length cDNA cloned into bacterial artificial chromosomes or plasmids are time-consuming and technically challenging. While the circular polymerase extension reaction (CPER) has been applied to RNA viruses, it has not been used for DNA viruses. Here, we successfully applied CPER to generate infectious recombinant adenoviruses (AdVs) of two serotypes. The resulting viruses replicated comparably to parental strains, and replication was confirmed by immunostaining. These findings demonstrate that CPER is a rapid and efficient platform for reverse genetics of DNA viruses and may accelerate AdV research and therapeutic development.

DOI： 10.1111/1348-0421.70016

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS Omega  

Although the SARS-CoV-2 pandemic has subsided with the widespread rollout of vaccines, emerging variants continue to pose significant public health challenges. While current diagnostic technologies can sensitively detect specific variants, there is an increasing need for broad-spectrum detection methods that are less affected by viral mutations. In particular, the development of diagnostic techniques that are not only broadly applicable but also rapid and cost-effective is highly desirable for large-scale screening and long-term surveillance. In this study, the applicability of a noncompetitive fluorescence polarization aptamer assay (NC-FPAA) was evaluated for detecting SARS-CoV-2, including both the wild-type strain and various variants. Two fluorescently labeled aptamers, a 77-mer (K1) and a 51-mer (M40), previously reported to have broad affinity for spike proteins of different SARS-CoV-2 variants, were used as probes. Detection experiments were conducted using eight SARS-CoV-2 variants, and specificity was further assessed using influenza viruses. The results demonstrate that NC-FPAA has the potential to serve as a diagnostic tool for the rapid, simple, and low-cost detection of multiple SARS-CoV-2 variants, thereby supporting broad and effective viral surveillance.

DOI： 10.1021/acsomega.5c06304

Web of Science

Scopus

PubMed

Language：English   Publisher：Journal of Virology  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is still circulating among humans, leading to the continuous evolution. SARS-CoV-2 Omicron JN.1 evolved from a distinct SARS-CoV-2 lineage, BA.2.86, and spread rapidly worldwide. It is unclear why BA.2.86 did not become dominant and was quickly replaced by JN.1, which possesses one amino acid substitution in the spike protein (S:L455S) and two in the non-spike proteins NSP6 and ORF7b (NSP6:R252K and ORF7b:F19L) compared to BA.2.86. Here, we utilized recombinant viruses to elucidate the impact of these mutations on the virological characteristics of JN.1. We found that the mutation in the spike attenuated viral replication, while the non-spike mutations acted synergistically to enhance replication. This suggests that the mutations in the non-spike proteins compensate for the one in the spike, improving viral fitness, as the mutations in the spike contribute to further immune evasion. Our findings suggest that functional changes in both the spike and non-spike proteins are necessary for the evolution of SARS-CoV-2, enabling evasion of adaptive immunity within the human population while sustaining replication.

DOI： 10.1128/jvi.00908-25

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Immunocompromised patients (ICPs), such as those who receive certain immunosuppressive therapies, occasionally experience prolonged viral infections even after antiviral treatment. In some cases, antiviral-resistant viruses may eventually emerge. Remdesivir (RDV) is an adenosine nucleoside analog that inhibits the activity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA polymerase, which is composed of a catalytic subunit known as nsp12. Previous studies have reported that amino acid mutations around loci 790–810 in nsp12 are responsible for RDV resistance. However, the host immune status that promotes the emergence of resistant viruses and their virological features remain unclear. We therefore collected clinical samples from 15 coronavirus disease 2019 (COVID-19) patients with various immunosuppressive conditions who received RDV. Variant analysis identified a total of seven nsp12 mutations—V792I, M794I, E796D, E796K, C799F, C799Y, and T803I—in 80 % (12/15) of the participants, with M794I and V792I the most prevalent. The identified mutations were more frequently observed in severely ICPs (including patients with hematological malignancies or kidney transplantation) compared to non-severely ICPs (including patients with solid cancers or autoimmune diseases). In vitro analysis using recombinant viruses carrying each identified mutation demonstrated that all mutant viruses were less efficient in growth compared to wildtype but with a 1.8-fold (T803I) to 3.6-fold (V792I) increase in the half maximal effective concentration (EC<inf>50</inf>) of RDV. The present study highlights the importance of monitoring resistance mutations to anti–SARS-CoV-2 drugs in severely ICPs.

DOI： 10.1016/j.antiviral.2025.106264

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Vaccination with mRNA vaccines has significantly reduced the SARS-CoV-2 mortality rate in the general population. However, the effectiveness of mRNA vaccines in kidney transplant (KTx) recipients is unclear. METHODS: In this cohort, we compared the disease severity and seroconversion rate after SARS-CoV-2 infection in 30 vaccinated and 8 unvaccinated KTx recipients. KTx recipients have infected between February 2022 and September 2023 during the Omicron variant phases. We measured anti-SARS-CoV-2 spike protein IgG antibodies (cutoff value was 1.0 AU/mL). Furthermore, we investigated anti-SARS-CoV-2 spike protein IgG antibodies and the neutralizing antibody titer against BA.5 and BA.2.86 in 10 vaccinated KTx recipients before and after BA.5 infection. RESULT: The incidence of moderate disease was significantly higher in the unvaccinated group (P = .004). The median antibody titers after SARS-CoV-2 infection in vaccinated and unvaccinated KTx recipients were 244.5 (IQR: 43.5-757.8) and <1 (IQR: <1-<1) AU/mL, respectively (P < .0001). Surprisingly, none of the 5 patients with moderate disease developed detectable antibodies after infection. The antibody titers and neutralizing antibody titer against BA.5 and BA.2.86 variants in vaccinated KTx recipients increased significantly after BA.5 infection (S-IgG: P = .004, BA.5: P = .002, BA.2.86: P = .016). CONCLUSIONS: Although vaccinated KTx recipients achieved IgG antibody and neutralizing antibody boost after SARS-CoV-2 infection, unvaccinated KTx recipients did not experience an increase in antibody titers and experienced more severe infections. Furthermore, KTx recipients acquired the neutralizing activity against Omicron BA.2.86 after Omicron BA.5 infection. Thus, vaccination should be recommended for KTx recipients.

DOI： 10.1016/j.transproceed.2025.05.021

PubMed

Language：English   Publisher：Cold Spring Harbor Laboratory  

The global circulation of SARS-CoV-2 in human populations has driven the emergence of Omicron subvariants, which have become highly diversified through recombination. In late 2024, SARS-CoV-2 Omicron XEC variant emerged from the recombination of two JN.1 progeny, KS.1.1 and KP.3.3, and became predominant worldwide. Here, we investigated virological features of the XEC variant. Epidemic dynamics modeling suggested that spike substitutions in XEC mainly contribute to its increased viral fitness. Additionally, four licensed antivirals were effective against XEC. Although the fusogenicity of XEC spike is comparable to that of the JN.1 spike, the intrinsic pathogenicity of XEC in hamsters was significantly higher than that of JN.1. Notably, we found that the nucleocapsid R204P mutation of XEC enhanced inflammation through NF-κB activation. Recent studies suggest that the evolutionary potential of spike protein is reaching its limit. Indeed, our findings highlight the critical role of non-spike mutations in the future evolution of SARS-CoV-2.

DOI： 10.1101/2025.05.28.656516

PubMed

Publisher：Cold Spring Harbor Laboratory  

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19), is still circulating among humans, leading to the continuous evolution. SARS-CoV-2 Omicron JN.1 evolved from a distinct SARS-CoV-2 lineage, BA.2.86, spread rapidly worldwide. It is unclear why BA.2.86 did not become dominant and was quickly replaced by JN.1, which possesses one amino acid substitution in the spike protein (S:L455S) and two in the non-spike proteins NSP6 and ORF7b (NSP6:R252K and ORF7b:F19L) compared to BA.2.86. Here, we utilized recombinant viruses to elucidate the impact of these mutations on the virological characteristics of JN.1. We found that the mutation in the spike attenuated viral replication, but the non-spike mutations enhanced replication, suggesting the mutations in the non-spike proteins compensate for the one in the spike to improve viral fitness, as the mutations in the spike contribute to further immune evasion. Our findings suggest that functional changes in both the spike and non-spike proteins are necessary in the evolution of SARS-CoV-2 to enable evasion of adaptive immunity within the human population while sustaining replication.

IMPORTANCE

Because the spike protein is strongly associated with certain virological properties of SARS-CoV-2, such as immune evasion and infectivity, most previous studies on SARS-CoV-2 variants have focused on spike protein mutations. However, the non-spike proteins also contribute to infectivity, as observed throughout the evolution of Omicron subvariants. In this study, we demonstrate a “trade-off” strategy in SARS-CoV-2 Omicron JN.1 in which the reduced infectivity caused by spike mutation is compensated by non-spike mutations. Our results provide insight into the evolutionary scenario of the emerging virus in the human population.

DOI： 10.1101/2025.02.17.638623

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1083/jcb.202109010

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Since 2019, SARS-CoV-2 has undergone mutations, resulting in pandemic and epidemic waves. The SARS-CoV-2 spike protein, crucial for cellular entry, binds to the ACE2 receptor exclusively when its receptor-binding domain (RBD) adopts the up-conformation. However, whether ACE2 also interacts with the RBD in the down-conformation to facilitate the conformational shift to RBD-up remains unclear. Herein, we present the structures of the BA.2.86 and the JN.1 spike proteins bound to ACE2. Notably, we successfully observed the ACE2-bound down-RBD, indicating an intermediate structure before the RBD-up conformation. The wider and mobile angle of RBDs in the up-state provides space for ACE2 to interact with the down-RBD, facilitating the transition to the RBD-up state. The K356T, but not N354-linked glycan, contributes to both of infectivity and neutralizing-antibody evasion in BA.2.86. These structural insights the spike-protein dynamics would help understand the mechanisms underlying SARS-CoV-2 infection and its neutralization.

DOI： 10.1038/s41467-024-52808-2

Scopus

Other Link： https://www.nature.com/articles/s41467-024-52808-2

Publisher：Mbio  

Due to the incessant emergence of various SARS-CoV-2 variants with enhanced fitness in the human population, controlling the COVID-19 pandemic has been challenging. Understanding how the virus enhances its fitness during a pandemic could offer valuable insights for more effective control of viral epidemics. In this manuscript, we review the evolution of SARS-CoV-2 from early 2022 to the end of 2023—from Omicron BA.2 to XBB descendants. Focusing on viral evolution during this period, we provide concrete examples that SARS-CoV-2 has increased its fitness by enhancing several functions of the spike (S) protein, including its binding affinity to the ACE2 receptor and its ability to evade humoral immunity. Furthermore, we explore how specific mutations modify these functions of the S protein through structural alterations. This review provides evolutionary, molecular, and structural insights into how SARS-CoV-2 has increased its fitness and repeatedly caused epidemic surges during the pandemic.

DOI： 10.1128/mbio.03220-23

Scopus

Language：English   Publisher：Microbiology and Immunology  

In middle to late 2023, a sublineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB, EG.5.1 (a progeny of XBB.1.9.2), is spreading rapidly around the world. We performed multiscale investigations, including phylogenetic analysis, epidemic dynamics modeling, infection experiments using pseudoviruses, clinical isolates, and recombinant viruses in cell cultures and experimental animals, and the use of human sera and antiviral compounds, to reveal the virological features of the newly emerging EG.5.1 variant. Our phylogenetic analysis and epidemic dynamics modeling suggested that two hallmark substitutions of EG.5.1, S:F456L and ORF9b:I5T are critical to its increased viral fitness. Experimental investigations on the growth kinetics, sensitivity to clinically available antivirals, fusogenicity, and pathogenicity of EG.5.1 suggested that the virological features of EG.5.1 are comparable to those of XBB.1.5. However, cryo-electron microscopy revealed structural differences between the spike proteins of EG.5.1 and XBB.1.5. We further assessed the impact of ORF9b:I5T on viral features, but it was almost negligible in our experimental setup. Our multiscale investigations provide knowledge for understanding the evolutionary traits of newly emerging pathogenic viruses, including EG.5.1, in the human population.

DOI： 10.1111/1348-0421.13165

Web of Science

Scopus

PubMed

Language：English   Publisher：John Wiley & Sons Australia, Ltd  

Pseudovirusを用いて検討した。系統学的分析にて、EG.5.1系統におけるスパイク(S)タンパク質にF456L、非Sタンパク質にORF9b:I5T変異を認め、ウイルス適応性が上昇していた。EG.5.1はXBB.1.5と似た特徴を有していたが、Sタンパク質の構造は異なっていた。ORF9b:I5Tについて、さらに検討したところ、その影響はほとんどみられなかった。EG.5.1スパイクタンパク質の受容体結合ドメインにおけるアンジオテンシン変換酵素2結合親和性はXBB.1.5より弱かった。

Language：English   Publishing type：Research paper (scientific journal)  

UNLABELLED: Rapid characterization of the causative agent(s) during a disease outbreak can aid in the implementation of effective control measures. However, isolation of the agent(s) from crude clinical samples can be challenging and time-consuming, hindering the establishment of countermeasures. In the present study, we used saliva specimens collected for the diagnosis of SARS-CoV-2-a good example of a practical target-and attempted to characterize the virus within the specimens without virus isolation. Thirty-four saliva samples from coronavirus disease 2019 patients were used to extract RNA and synthesize DNA amplicons by PCR. New primer sets were designed to generate DNA amplicons of the full-length spike (S) gene for subsequent use in a circular polymerase extension reaction (CPER), a simple method for deriving recombinant viral genomes. According to the S sequence, four clinical specimens were classified as BA. 1, BA.2, BA.5, and XBB.1 and were used for the de novo generation of recombinant viruses carrying the entire S gene. Additionally, chimeric viruses carrying the gene encoding GFP were generated to evaluate viral propagation using a plate reader. We successfully used the RNA purified directly from clinical saliva samples to generate chimeric viruses carrying the entire S gene by our updated CPER method. The chimeric viruses exhibited robust replication in cell cultures with similar properties. Using the recombinant GFP viruses, we also successfully characterized the efficacy of the licensed antiviral AZD7442. Our proof-of-concept demonstrates the novel utility of CPER to allow rapid characterization of viruses from clinical specimens. IMPORTANCE: Characterization of the causative agent(s) for infectious diseases helps in implementing effective control measurements, especially in outbreaks. However, the isolation of the agent(s) from clinical specimens is often challenging and time-consuming. In this study, saliva samples from coronavirus disease 2019 patients were directly subjected to purifying viral RNA, synthesizing DNA amplicons for sequencing, and generating recombinant viruses. Utilizing an updated circular polymerase extension reaction method, we successfully generated chimeric SARS-CoV-2 viruses with sufficient in vitro replication capacity and antigenicity. Thus, the recombinant viruses generated in this study were applicable for evaluating the antivirals. Collectively, our developed method facilitates rapid characterization of specimens circulating in hosts, aiding in the establishment of control measurements. Additionally, this approach offers an advanced strategy for controlling other (re-)emerging viral infectious diseases.

DOI： 10.1128/jcm.00042-24

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the largest single-stranded RNA virus known to date. Its genome contains multiple accessory protein genes that act against host immune responses but are not required for progeny virus production. The functions of the accessory proteins in the viral life cycle have been examined, but their involvement in viral pathogenicity remains unclear. Here, we investigated the roles of the accessory proteins in viral immunopathogenicity. To this end, recombinant SARS-CoV-2 possessing nonsense mutations in the seven accessory protein open reading frames (ORFs) (ORF3a, ORF3b, ORF6, ORF7a, ORF8, ORF9b, and ORF10) was de novo generated using an early pandemic SARS-CoV-2 strain as a backbone. We confirmed that the resultant virus (termed ORF3-10 KO) did not express accessory proteins in infected cells and retained the desired mutations in the viral genome. In cell culture, the ORF3-10 KO virus exhibited similar virus growth kinetics as the parental virus. In hamsters, ORF3-10 KO virus infection resulted in mild weight loss and reduced viral replication in the oral cavity and lung tissue. ORF3-10 KO virus infection led to mild inflammation, indicating that an inability to evade innate immune sensing because of a lack of accessory proteins impairs virus growth in vivo and results in quick elimination from the body. Overall, we showed that SARS-CoV-2 accessory proteins are involved in immunopathogenicity.

DOI： 10.1111/1348-0421.13157

PubMed

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.ebiom.2024.105181

Language：English   Publishing type：Research paper (scientific journal)  

Reverse genetics systems have played a central role in developing recombinant viruses for a wide spectrum of virus research. The circular polymerase extension reaction (CPER) method has been applied to studying positive-strand RNA viruses, allowing researchers to bypass molecular cloning of viral cDNA clones and thus leading to the rapid generation of recombinant viruses. However, thus far, the CPER protocol has only been established using cap-dependent RNA viruses. Here, we demonstrate that a modified version of the CPER method can be successfully applied to positive-strand RNA viruses that use cap-independent, internal ribosomal entry site (IRES)-mediated translation. As a proof-of-concept, we employed mammalian viruses with different types (classes I, II, and III) of IRES to optimize the CPER method. Using the hepatitis C virus (HCV, class III), we found that inclusion in the CPER assembly of an RNA polymerase I promoter and terminator, instead of those from polymerase II, allowed greater viral production. This approach was also successful in generating recombinant bovine viral diarrhea virus (class III) following transfection of MDBK/293T co-cultures to overcome low transfection efficiency. In addition, we successfully generated the recombinant viruses from clinical specimens. Our modified CPER could be used for producing hepatitis A virus (HAV, type I) as well as de novo generation of encephalomyocarditis virus (type II). Finally, we generated recombinant HCV and HAV reporter viruses that exhibited replication comparable to that of the wild-type parental viruses. The recombinant HAV reporter virus helped evaluate antivirals. Taking the findings together, this study offers methodological advances in virology.IMPORTANCEThe lack of versatility of reverse genetics systems remains a bottleneck in viral research. Especially when (re-)emerging viruses reach pandemic levels, rapid characterization and establishment of effective countermeasures using recombinant viruses are beneficial in disease control. Indeed, numerous studies have attempted to establish and improve the methods. The circular polymerase extension reaction (CPER) method has overcome major obstacles in generating recombinant viruses. However, this method has not yet been examined for positive-strand RNA viruses that use cap-independent, internal ribosome entry site-mediated translation. Here, we engineered a suitable gene cassette to expand the CPER method for all positive-strand RNA viruses. Furthermore, we overcame the difficulty of generating recombinant viruses because of low transfection efficiency. Using this modified method, we also successfully generated reporter viruses and recombinant viruses from a field sample without virus isolation. Taking these findings together, our adapted methodology is an innovative technology that could help advance virologic research.

DOI： 10.1128/jvi.01638-23

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

In late 2023, several SARS-CoV-2 XBB descendants, notably EG.5.1, were predominant worldwide. However, a distinct SARS-CoV-2 lineage, the BA.2.86 variant, also emerged. BA.2.86 is phylogenetically distinct from other Omicron sublineages, accumulating over 30 amino acid mutations in its spike protein. Here, we examined the virological characteristics of the BA.2.86 variant. Our epidemic dynamics modeling suggested that the relative reproduction number of BA.2.86 is significantly higher than that of EG.5.1. Additionally, four clinically available antivirals were effective against BA.2.86. Although the fusogenicity of BA.2.86 spike is similar to that of the parental BA.2 spike, the intrinsic pathogenicity of BA.2.86 in hamsters was significantly lower than that of BA.2. Since the growth kinetics of BA.2.86 are significantly lower than those of BA.2 both in vitro and in vivo, the attenuated pathogenicity of BA.2.86 is likely due to its decreased replication capacity. These findings uncover the features of BA.2.86, providing insights for control and treatment.

DOI： 10.1016/j.chom.2024.01.001

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer  

Circulation of SARS-CoV-2 Omicron XBB has resulted in the emergence of XBB.1.5, a new Variant of Interest. Our phylogenetic analysis suggests that XBB.1.5 evolved from XBB.1 by acquiring the S486P spike (S) mutation, subsequent to the acquisition of a nonsense mutation in ORF8. Neutralization assays showed similar abilities of immune escape between XBB.1.5 and XBB.1. We determine the structural basis for the interaction between human ACE2 and the S protein of XBB.1.5, showing similar overall structures between the S proteins of XBB.1 and XBB.1.5. We provide the intrinsic pathogenicity of XBB.1 and XBB.1.5 in hamsters. Importantly, we find that the ORF8 nonsense mutation of XBB.1.5 resulted in impairment of MHC suppression. In vivo experiments using recombinant viruses reveal that the XBB.1.5 mutations are involved with reduced virulence of XBB.1.5. Together, our study identifies the two viral functions defined the difference between XBB.1 and XBB.1.5.

DOI： 10.1038/s41467-024-45274-3

Web of Science

Scopus

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

A digital platform that can rapidly and accurately diagnose pathogenic viral variants, including SARS-CoV-2, will minimize pandemics, public anxiety, and economic losses. We recently reported an artificial intelligence (AI)-nanopore platform that enables testing for Wuhan SARS-CoV-2 with high sensitivity and specificity within five minutes. However, which parts of the virus are recognized by the platform are unknown. Similarly, whether the platform can detect SARS-CoV-2 variants or the presence of the virus in clinical samples needs further study. Here, we demonstrated the platform can distinguish SARS-CoV-2 variants. Further, it identified mutated Wuhan SARS-CoV-2 expressing spike proteins of the delta and omicron variants, indicating it discriminates spike proteins. Finally, we used the platform to identify omicron variants with a sensitivity and specificity of 100% and 94%, respectively, in saliva specimens from COVID-19 patients. Thus, our results demonstrate the AI-nanopore platform is an effective diagnostic tool for SARS-CoV-2 variants.

DOI： 10.1039/d3lc00572k

PubMed

Publishing type：Research paper (scientific journal)   Publisher：American Society for Microbiology  

ABSTRACT

Differences in host angiotensin converting enzyme 2 (ACE2) genes may affect the host range of SARS-CoV-2-related coronaviruses (SC2r-CoVs) and further determine the tropism of host ACE2 for the infection receptor. However, the factor(s) responsible for determining the host tropism of SC2r-CoVs, which may in part be determined by the tropism of host ACE2 usage, remains unclear. Here, we use the pseudoviruses with the spike proteins of two Laotian SC2r-CoVs, BANAL-20-236 and BANAL-20-52, and the cells expressing ACE2 proteins of eight different Rhinolophus bat species to show that these two spikes have different tropisms for Rhinolophus bat ACE2. Through structural analysis and cell culture experiments, we demonstrate that this tropism is determined by residue 493 of the spike and residues 31 and 35 of ACE2. Our results suggest that SC2r-CoVs exhibit differential ACE2 tropism, which may be driven by adaptation to different Rhinolophus bat ACE2 proteins.

IMPORTANCE

The efficiency of infection receptor use is the first step in determining the species tropism of viruses. After the coronavirus disease 2019 pandemic, a number of SARS-CoV-2-related coronaviruses (SC2r-CoVs) were identified in Rhinolophus bats, and some of them can use human angiotensin converting enzyme 2 (ACE2) for the infection receptor without acquiring additional mutations. This means that the potential of certain SC2r-CoVs to cause spillover from bats to humans is "off-the-shelf." However, both SC2r-CoVs and Rhinolophus bat species are highly diversified, and the host tropism of SC2r-CoVs remains unclear. Here, we focus on two Laotian SC2r-CoVs, BANAL-20-236 and BANAL-20-52, and determine how the tropism of SC2r-CoVs to Rhinolophus bat ACE2 is determined at the amino acid resolution level.

DOI： 10.1128/jvi.00990-23

Publisher：Cold Spring Harbor Laboratory  

Summary

Monitoringin vivoviral dynamics can improve our understanding of pathogenicity and tissue tropism. For positive-sense, single-stranded RNA viruses, several studies have attempted to monitor viral kineticsin vivousing reporter genomes. The application of such recombinant viruses can be limited by challenges in accommodating bioluminescent reporter genes in the viral genome. Conventional luminescence also exhibits relatively low tissue permeability and thus less sensitivity for visualizationin vivo. Here we show that unlike NanoLuc bioluminescence, the improved method, termed AkaBLI, allows visualization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Syrian hamsters. By successfully incorporating a codon-optimized Akaluc luciferase gene into the SARS-CoV-2 genome, we visualizedin vivoinfection, including the tissue-specific differences associated with particular variants. Additionally, we could evaluate the efficacy of neutralizing antibodies and mRNA vaccination by monitoring changes in Akaluc signals. Overall, AkaBLI is an effective technology for monitoring viral dynamics in live animals.

DOI： 10.1101/2023.10.12.561993

Language：English   Publishing type：Research paper (scientific journal)  

Previous studies on the Omicron BA.2 variant suggested that the virological characteristics of BA.2 are determined by the mutations in at least two different regions of the viral genome: in the BA.2 spike gene (enhancing viral fusogenicity and intrinsic pathogenicity) and the non-spike region of the BA.2 genome (leading to intrinsic pathogenicity attenuation). However, the mutations modulating the BA.2 virological properties remain elusive. In this study, we demonstrated that the L371F substitution in the BA.2 spike protein confers greater fusogenicity and intrinsic pathogenicity. Furthermore, we revealed that multiple mutations downstream of the spike gene in the BA.2 genome are responsible for attenuating intrinsic viral pathogenicity and replication capacity. As mutations in the SARS-CoV-2 variant spike proteins could modulate certain virological properties, such as immune evasion and infectivity, most studies have previously focused on spike protein mutations. Our results underpin the importance of non-spike protein-related mutations in SARS-CoV-2 variants. IMPORTANCE Most studies investigating the characteristics of emerging SARS-CoV-2 variants have been focusing on mutations in the spike proteins that affect viral infectivity, fusogenicity, and pathogenicity. However, few studies have addressed how naturally occurring mutations in the non-spike regions of the SARS-CoV-2 genome impact virological properties. In this study, we proved that multiple SARS-CoV-2 Omicron BA.2 mutations, one in the spike protein and another downstream of the spike gene, orchestrally characterize this variant, shedding light on the importance of Omicron BA.2 mutations out of the spike protein.

DOI： 10.1128/jvi.01011-23

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Communications Biology  

The unremitting emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants necessitates ongoing control measures. Given its rapid spread, the new Omicron subvariant BA.5 requires urgent characterization. Here, we comprehensively analyzed BA.5 with the other Omicron variants BA.1, BA.2, and ancestral B.1.1. Although in vitro growth kinetics of BA.5 was comparable among the Omicron subvariants, BA.5 was much more fusogenic than BA.1 and BA.2. Airway-on-a-chip analysis showed that, among Omicron subvariants, BA.5 had enhanced ability to disrupt the respiratory epithelial and endothelial barriers. Furthermore, in our hamster model, in vivo pathogenicity of BA.5 was slightly higher than that of the other Omicron variants and less than that of ancestral B.1.1. Notably, BA.5 gains efficient virus spread compared with BA.1 and BA.2, leading to prompt immune responses. Our findings suggest that BA.5 has low pathogenicity compared with the ancestral strain but enhanced virus spread /inflammation compared with earlier Omicron subvariants.

DOI： 10.1038/s42003-023-05081-w

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Several vaccines have been widely used to counteract the global pandemic caused by SARS-CoV-2. However, due to the rapid emergence of SARS-CoV-2 variants of concern (VOCs), further development of vaccines that confer broad and longer-lasting protection against emerging VOCs are needed. Here, we report the immunological characteristics of a self-amplifying RNA (saRNA) vaccine expressing the SARS-CoV-2 Spike (S) receptor binding domain (RBD), which is membrane-anchored by fusing with an N-terminal signal sequence and a C-terminal transmembrane domain (RBD-TM). Immunization with saRNA RBD-TM delivered in lipid nanoparticles (LNP) efficiently induces T-cell and B-cell responses in non-human primates (NHPs). In addition, immunized hamsters and NHPs are protected against SARS-CoV-2 challenge. Importantly, RBD-specific antibodies against VOCs are maintained for at least 12 months in NHPs. These findings suggest that this saRNA platform expressing RBD-TM will be a useful vaccine candidate inducing durable immunity against emerging SARS-CoV-2 strains.

DOI： 10.1038/s41467-023-38457-x

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer  

In late 2022, various Omicron subvariants emerged and cocirculated worldwide. These variants convergently acquired amino acid substitutions at critical residues in the spike protein, including residues R346, K444, L452, N460, and F486. Here, we characterize the convergent evolution of Omicron subvariants and the properties of one recent lineage of concern, BQ.1.1. Our phylogenetic analysis suggests that these five substitutions are recurrently acquired, particularly in younger Omicron lineages. Epidemic dynamics modelling suggests that the five substitutions increase viral fitness, and a large proportion of the fitness variation within Omicron lineages can be explained by these substitutions. Compared to BA.5, BQ.1.1 evades breakthrough BA.2 and BA.5 infection sera more efficiently, as demonstrated by neutralization assays. The pathogenicity of BQ.1.1 in hamsters is lower than that of BA.5. Our multiscale investigations illuminate the evolutionary rules governing the convergent evolution for known Omicron lineages as of 2022.

DOI： 10.1038/s41467-023-38188-z

Web of Science

Scopus

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.isci.2023.106652

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Mutations continue to accumulate within the SARS-CoV-2 genome, and the ongoing epidemic has shown no signs of ending. It is critical to predict problematic mutations that may arise in clinical environments and assess their properties in advance to quickly implement countermeasures against future variant infections. In this study, we identified mutations resistant to remdesivir, which is widely administered to SARS-CoV-2-infected patients, and discuss the cause of resistance. First, we simultaneously constructed eight recombinant viruses carrying the mutations detected in in vitro serial passages of SARS-CoV-2 in the presence of remdesivir. We confirmed that all the mutant viruses didn’t gain the virus production efficiency without remdesivir treatment. Time course analyses of cellular virus infections showed significantly higher infectious titers and infection rates in mutant viruses than wild type virus under treatment with remdesivir. Next, we developed a mathematical model in consideration of the changing dynamic of cells infected with mutant viruses with distinct propagation properties and defined that mutations detected in in vitro passages canceled the antiviral activities of remdesivir without raising virus production capacity. Finally, molecular dynamics simulations of the NSP12 protein of SARS-CoV-2 revealed that the molecular vibration around the RNA-binding site was increased by the introduction of mutations on NSP12. Taken together, we identified multiple mutations that affected the flexibility of the RNA binding site and decreased the antiviral activity of remdesivir. Our new insights will contribute to developing further antiviral measures against SARS-CoV-2 infection.

DOI： 10.1371/journal.ppat.1011231

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Echinocandin antifungal drugs, including micafungin, anidulafungin, and caspofungin, have been recently reported to exhibit antiviral effects against various viruses such as flavivirus, alphavirus, and coronavirus. In this study, we focused on micafungin and its derivatives and analyzed their antiviral activities against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The micafungin derivatives Mi-2 and Mi-5 showed higher antiviral activity than micafungin, with 50% maximal inhibitory concentration (IC50) of 5.25 and 6.51 µM, respectively (3.8 to 4.7-fold stronger than micafungin) and 50% cytotoxic concentration (CC50) of >64 µM in VeroE6/TMPRSS2 cells. This high anti-SARS-CoV-2 activity was also conserved in human lung epithelial cell-derived Calu-3 cells. Micafungin, Mi-2, and Mi-5 were suggested to inhibit the intracellular virus replication process; additionally, these compounds were active against SARS-CoV-2 variants, including Delta (AY.122, hCoV-19/Japan/TY11-927/2021), Omicron (BA.1.18, hCoV-19/Japan/TY38-873/2021), a variant resistant to remdesivir (R10/E796G C799F), and a variant resistant to casirivimab/imdevimab antibody cocktail (E406W); thus, our results provide basic evidence for the potential use of micafungin derivatives for developing antiviral agents.

DOI： 10.3390/v15020452

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Nature  

In late 2022, SARS-CoV-2 Omicron subvariants have become highly diversified, and XBB is spreading rapidly around the world. Our phylogenetic analyses suggested that XBB emerged through the recombination of two cocirculating BA.2 lineages, BJ.1 and BM.1.1.1 (a progeny of BA.2.75), during the summer of 2022. XBB.1 is the variant most profoundly resistant to BA.2/5 breakthrough infection sera to date and is more fusogenic than BA.2.75. The recombination breakpoint is located in the receptor-binding domain of spike, and each region of the recombinant spike confers immune evasion and increases fusogenicity. We further provide the structural basis for the interaction between XBB.1 spike and human ACE2. Finally, the intrinsic pathogenicity of XBB.1 in male hamsters is comparable to or even lower than that of BA.2.75. Our multiscale investigation provides evidence suggesting that XBB is the first observed SARS-CoV-2 variant to increase its fitness through recombination rather than substitutions.

DOI： 10.1038/s41467-023-38435-3

Web of Science

Scopus

PubMed

CiNii Research

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.xpro.2022.101773

Publisher：Cold Spring Harbor Laboratory  

Summary

BACKGROUND

VLPCOV-01 is a lipid nanoparticle-encapsulated self-amplifying RNA (saRNA) vaccine that expresses a membrane-anchored receptor-binding domain (RBD) derived from the SARS-CoV-2 spike protein.

METHODS

A phase 1 study of VLPCOV-01 was conducted at Medical Corporation Heishinkai OPHAC Hospital, Japan. Participants aged 18 to 55 or ≥65 years who had completed two doses of the BNT162b2 mRNA vaccine 6 to 12 months previously were randomised to receive one intramuscular vaccination of 0·3, 1·0, or 3·0 μg VLPCOV-01, 30 μg BNT162b2, or placebo between February 16, 2022, and March 17, 2022. Solicited adverse events were collected up to 6 days post-administration. Interim immunogenicity analyses included SARS-CoV-2 IgG and neutralising antibody titres. Follow-up for safety and immunogenicity evaluation is ongoing. (The trial is registered: jRCT2051210164).

FINDINGS

92 healthy adults were enrolled, with 60 participants receiving VLPCOV-01. No serious adverse events were reported up to 26 weeks, and no prespecified trial-halting events were met. VLPCOV-01 induced robust IgG titres against SARS-CoV-2 RBD protein that were maintained up to 26 weeks in non-elderly participants, with geometric means ranging from 5037 (95% CI 1272–19,940) at 0·3 μg to 12,873 (95% CI 937–17,686) at 3 μg, in comparison to 3166 (95% CI 1619–6191) with 30 μg BNT162b2. Among elderly participants, IgG titres at 26 weeks post-vaccination with 3 μg VLPCOV-01 were 9865 (95% CI 4396–22138) compared to 4183 (95% CI 1436–12180) following vaccination with 30 μg BNT162b2. Pseudovirus neutralising antibody responses were observed against multiple SARS-CoV-2 variants and strongly correlated with anti-SARS-CoV-2 IgG (r=0·950, p&lt;0·001).

INTERPRETATION

VLPCOV-01 is immunogenic following low dose administration, with anti-SARS-CoV-2 immune responses comparable to BNT162b2. These findings support further development of VLPCOV-01 as a COVID-19 booster vaccine and the potential for saRNA vectors as a vaccine platform.

FUNDING

Supported by AMED, Grant No. JP21nf0101627.

DOI： 10.1101/2022.11.21.22281000

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

The SARS-CoV-2 Omicron BA.2.75 variant emerged in May 2022. BA.2.75 is a BA.2 descendant but is phylogenetically distinct from BA.5, the currently predominant BA.2 descendant. Here, we show that BA.2.75 has a greater effective reproduction number and different immunogenicity profile than BA.5. We determined the sensitivity of BA.2.75 to vaccinee and convalescent sera as well as a panel of clinically available antiviral drugs and antibodies. Antiviral drugs largely retained potency but antibody sensitivity varied depending on several key BA.2.75-specific substitutions. The BA.2.75 spike exhibited a profoundly higher affinity for its human receptor, ACE2. Additionally, the fusogenicity, growth efficiency in human alveolar epithelial cells, and intrinsic pathogenicity in hamsters of BA.2.75 were greater than those of BA.2. Our multilevel investigations suggest that BA.2.75 acquired virological properties independent of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5.

DOI： 10.1016/j.chom.2022.10.003

Web of Science

Scopus

PubMed

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

The Omicron emerged in November 2021 and became the predominant SARS-CoV-2 variant globally. It spreads more rapidly than ancestral lineages and its rapid detection is critical for the prevention of disease outbreaks. Antigen tests such as immunochromatographic assay (ICA) and chemiluminescent enzyme immunoassay (CLEIA) yield results more quickly than standard polymerase chain reaction (PCR). However, their utility for the detection of the Omicron variant remains unclear. We herein evaluated the performance of ICA and CLEIA in saliva from 51 patients with Omicron and 60 PCR negative individuals. The sensitivity and specificity of CLEIA were 98.0% (95%CI: 89.6-100.0%) and 100.0% (95%CI: 94.0-100.0%), respectively, with fine correlation with cycle threshold (Ct) values. The sensitivity and specificity of ICA were 58.8% (95%CI: 44.2-72.4%) and 100.0% (95%CI: 94.0-100.0%), respectively. The sensitivity of ICA was 100.0% (95%CI: 80.5-100.0%) when PCR Ct was less than 25. The Omicron can be efficiently detected in saliva by CLEIA. ICA also detects high viral load Omicron using saliva.

DOI： 10.1016/j.jcvp.2022.100109

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cell  

After the global spread of the SARS-CoV-2 Omicron BA.2, some BA.2 subvariants, including BA.2.9.1, BA.2.11, BA.2.12.1, BA.4, and BA.5, emerged in multiple countries. Our statistical analysis showed that the effective reproduction numbers of these BA.2 subvariants are greater than that of the original BA.2. Neutralization experiments revealed that the immunity induced by BA.1/2 infections is less effective against BA.4/5. Cell culture experiments showed that BA.2.12.1 and BA.4/5 replicate more efficiently in human alveolar epithelial cells than BA.2, and particularly, BA.4/5 is more fusogenic than BA.2. We further provided the structure of the BA.4/5 spike receptor-binding domain that binds to human ACE2 and considered how the substitutions in the BA.4/5 spike play roles in ACE2 binding and immune evasion. Moreover, experiments using hamsters suggested that BA.4/5 is more pathogenic than BA.2. Our multiscale investigations suggest that the risk of BA.2 subvariants, particularly BA.4/5, to global health is greater than that of original BA.2.

DOI： 10.1016/j.cell.2022.09.018

Web of Science

Scopus

PubMed

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jphs.2022.04.001

Scopus

PubMed

Language：English   Publisher：(公社)日本薬理学会  

シクレソニド(CIC)のアセタール部位とエステル部位を加水分解して得たCIC-ジオール(16α-ヒドロキシプレドニゾロン)を原料として16種類のCIC-アセタール誘導体をデザイン・合成し、抗重症急性呼吸器症候群コロナウイルス2型(SARS-CoV-2)活性を比較した。その結果、これらのCIC-アセタール誘導体のうち、直鎖アルキル鎖を持つ数種のCIC-アセタール誘導体がCIC-2と比較して強力なウイルスコピー数減少活性を示した。

Language：English   Publishing type：Research paper (scientific journal)  

Flaviviruses, which are globally distributed and cause a spectrum of potentially severe illnesses, pose a major threat to public health. Although Flaviviridae viruses, including flaviviruses, possess similar genome structures, only the flaviviruses encode the non-structural protein NS1, which resides in the endoplasmic reticulum (ER) and is secreted from cells after oligomerization. The ER-resident NS1 is known to be involved in viral genome replication, but the essential roles of secretory NS1 in the virus life cycle are not fully understood. Here we characterized the roles of secretory NS1 in the particle formation of flaviviruses. We first identified an amino acid residue essential for the NS1 secretion but not for viral genome replication by using protein-protein interaction network analyses and mutagenesis scanning. By using the recombinant flaviviruses carrying the identified NS1 mutation, we clarified that the mutant flaviviruses employed viral genome replication. We then constructed a recombinant NS1 with the identified mutation and demonstrated by physicochemical assays that the mutant NS1 was unable to form a proper oligomer or associate with liposomes. Finally, we showed that the functions of NS1 that were lost by the identified mutation could be compensated for by the in trans-expression of Erns of pestiviruses and host exchangeable apolipoproteins, which participate in the infectious particle formation of pestiviruses and hepaciviruses in the family Flaviviridae, respectively. Collectively, our study suggests that secretory NS1 plays a role in the particle formation of flaviviruses through its interaction with the lipid membrane.

DOI： 10.1371/journal.ppat.1010593

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Soon after the emergence and global spread of the SARS-CoV-2 Omicron lineage BA.1, another Omicron lineage, BA.2, began outcompeting BA.1. The results of statistical analysis showed that the effective reproduction number of BA.2 is 1.4-fold higher than that of BA.1. Neutralization experiments revealed that immunity induced by COVID vaccines widely administered to human populations is not effective against BA.2, similar to BA.1, and that the antigenicity of BA.2 is notably different from that of BA.1. Cell culture experiments showed that the BA.2 spike confers higher replication efficacy in human nasal epithelial cells and is more efficient in mediating syncytia formation than the BA.1 spike. Furthermore, infection experiments using hamsters indicated that the BA.2 spike-bearing virus is more pathogenic than the BA.1 spike-bearing virus. Altogether, the results of our multiscale investigations suggest that the risk of BA.2 to global health is potentially higher than that of BA.1.

DOI： 10.1016/j.cell.2022.04.035

PubMed

Language：English  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：English  

Language：Japanese  

Language：Japanese  

J-GLOBAL

J-GLOBAL

J-GLOBAL

J-GLOBAL

J-GLOBAL

J-GLOBAL