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3.
Proc Natl Acad Sci U S A ; 119(37): e2204717119, 2022 09 13.
Article in English | MEDLINE | ID: covidwho-2017032

ABSTRACT

The ongoing COVID-19 pandemic is a major public health crisis. Despite the development and deployment of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pandemic persists. The continued spread of the virus is largely driven by the emergence of viral variants, which can evade the current vaccines through mutations in the spike protein. Although these differences in spike are important in terms of transmission and vaccine responses, these variants possess mutations in the other parts of their genome that may also affect pathogenesis. Of particular interest to us are the mutations present in the accessory genes, which have been shown to contribute to pathogenesis in the host through interference with innate immune signaling, among other effects on host machinery. To examine the effects of accessory protein mutations and other nonspike mutations on SARS-CoV-2 pathogenesis, we synthesized both viruses possessing deletions in the accessory genes as well as viruses where the WA-1 spike is replaced by each variant spike gene in a SARS-CoV-2/WA-1 infectious clone. We then characterized the in vitro and in vivo replication of these viruses and compared them to both WA-1 and the full variant viruses. Our work has revealed that the accessory proteins contribute to SARS-CoV-2 pathogenesis and the nonspike mutations in variants can contribute to replication of SARS-CoV-2 and pathogenesis in the host. This work suggests that while spike mutations may enhance receptor binding and entry into cells, mutations in accessory proteins may alter clinical disease presentation.


Subject(s)
COVID-19 , Mutation , SARS-CoV-2 , Viral Regulatory and Accessory Proteins , Virulence , COVID-19/virology , Humans , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Viral Regulatory and Accessory Proteins/genetics , Virulence/genetics , Virus Replication/genetics
6.
J Virol ; 96(17): e0058222, 2022 09 14.
Article in English | MEDLINE | ID: covidwho-1992936

ABSTRACT

Emerging variants, especially the recent Omicron variant, and gaps in vaccine coverage threaten mRNA vaccine mediated protection against SARS-CoV-2. While children have been relatively spared by the ongoing pandemic, increasing case numbers and hospitalizations are now evident among children. Thus, it is essential to better understand the magnitude and breadth of vaccine-induced immunity in children against circulating viral variant of concerns (VOCs). Here, we compared the magnitude and breadth of humoral immune responses in adolescents and adults 1 month after the two-dose Pfizer (BNT162b2) vaccination. We found that adolescents (aged 11 to 16) demonstrated more robust binding antibody and neutralization responses against the wild-type SARS-CoV-2 virus spike protein contained in the vaccine compared to adults (aged 27 to 55). The quality of the antibody responses against VOCs in adolescents were very similar to adults, with modest changes in binding and neutralization of Beta, Gamma, and Delta variants. In comparison, a significant reduction of binding titers and a striking lack of neutralization was observed against the newly emerging Omicron variant for both adolescents and adults. Overall, our data show that a two-dose BNT162b2 vaccine series may be insufficient to protect against the Omicron variant. IMPORTANCE While plasma binding and neutralizing antibody responses have been reported for cohorts of infected and vaccinated adults, much less is known about the vaccine-induced antibody responses to variants including Omicron in children. This illustrates the need to characterize vaccine efficacy in key vulnerable populations. A third (booster) dose of BNTb162b was approved for children 12 to 15 years of age by the Food and Drug Administration (FDA) on January 1, 2022, and pediatric clinical trials are under way to evaluate the safety, immunogenicity, and effectiveness of a third dose in younger children. Similarly, variant-specific booster doses and pan-coronavirus vaccines are areas of active research. Our data show adolescents mounted stronger humoral immune responses after vaccination than adults. It also highlights the need for future studies of antibody durability in adolescents and children as well as the need for future studies of booster vaccination and their efficacy against the Omicron variant.


Subject(s)
Antibodies, Viral , Antibody Formation , BNT162 Vaccine , COVID-19 , SARS-CoV-2 , Adolescent , Adult , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , BNT162 Vaccine/administration & dosage , BNT162 Vaccine/immunology , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Child , Humans , Immunization, Secondary , SARS-CoV-2/classification , SARS-CoV-2/immunology
7.
mBio ; 13(4): e0194422, 2022 08 30.
Article in English | MEDLINE | ID: covidwho-1986333

ABSTRACT

The human upper respiratory tract, specifically the nasopharyngeal epithelium, is the entry portal and primary infection site of respiratory viruses. Productive infection of SARS-CoV-2 in the nasal epithelium constitutes the cellular basis of viral pathogenesis and transmissibility. Yet a robust and well-characterized in vitro model of the nasal epithelium remained elusive. Here we report an organoid culture system of the nasal epithelium. We derived nasal organoids from easily accessible nasal epithelial cells with a perfect establishment rate. The derived nasal organoids were consecutively passaged for over 6 months. We then established differentiation protocols to generate 3-dimensional differentiated nasal organoids and organoid monolayers of 2-dimensional format that faithfully simulate the nasal epithelium. Moreover, when differentiated under a slightly acidic pH, the nasal organoid monolayers represented the optimal correlate of the native nasal epithelium for modeling the high infectivity of SARS-CoV-2, superior to all existing organoid models. Notably, the differentiated nasal organoid monolayers accurately recapitulated higher infectivity and replicative fitness of the Omicron variant than the prior variants. SARS-CoV-2, especially the more transmissible Delta and Omicron variants, destroyed ciliated cells and disassembled tight junctions, thereby facilitating virus spread and transmission. In conclusion, we establish a robust organoid culture system of the human nasal epithelium for modeling upper respiratory infections and provide a physiologically-relevant model for assessing the infectivity of SARS-CoV-2 emerging variants. IMPORTANCE An in vitro model of the nasal epithelium is imperative for understanding cell biology and virus-host interaction in the human upper respiratory tract. Here we report an organoid culture system of the nasal epithelium. Nasal organoids were derived from readily accessible nasal epithelial cells with perfect efficiency and stably expanded for more than 6 months. The long-term expandable nasal organoids were induced maturation into differentiated nasal organoids that morphologically and functionally simulate the nasal epithelium. The differentiated nasal organoids adequately recapitulated the higher infectivity and replicative fitness of SARS-CoV-2 emerging variants than the ancestral strain and revealed viral pathogenesis such as ciliary damage and tight junction disruption. Overall, we established a human nasal organoid culture system that enables a highly efficient reconstruction and stable expansion of the human nasal epithelium in culture plates, thus providing a facile and robust tool in the toolbox of microbiologists.


Subject(s)
COVID-19 , Nasal Mucosa , Organoids , SARS-CoV-2 , COVID-19/virology , Humans , Nasal Mucosa/virology , Organoids/virology , SARS-CoV-2/classification , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Tissue Culture Techniques
8.
Emerg Infect Dis ; 28(9): 1920-1923, 2022 09.
Article in English | MEDLINE | ID: covidwho-1974606

ABSTRACT

We detected a highly divergent SARS-CoV-2 Alpha variant in an immunocompromised person several months after the latest detection of the Alpha variant in the Netherlands. The patient was infected for 42 weeks despite several treatment regimens and disappearance of most clinical symptoms. We identified several potential immune escape mutations in the spike protein.


Subject(s)
COVID-19 , Mutation , SARS-CoV-2 , COVID-19/immunology , Humans , Immunocompromised Host , Netherlands , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics
9.
BMJ ; 378: e070695, 2022 08 02.
Article in English | MEDLINE | ID: covidwho-1968217

ABSTRACT

OBJECTIVE: To assess the risk of covid-19 death after infection with omicron BA.1 compared with delta (B.1.617.2). DESIGN: Retrospective cohort study. SETTING: England, United Kingdom, from 1 December 2021 to 30 December 2021. PARTICIPANTS: 1 035 149 people aged 18-100 years who tested positive for SARS-CoV-2 under the national surveillance programme and had an infection identified as omicron BA.1 or delta compatible. MAIN OUTCOME MEASURES: The main outcome measure was covid-19 death as identified from death certification records. The exposure of interest was the SARS-CoV-2 variant identified from NHS Test and Trace PCR positive tests taken in the community (pillar 2) and analysed by Lighthouse laboratories. Cause specific Cox proportional hazard regression models (censoring non-covid-19 deaths) were adjusted for sex, age, vaccination status, previous infection, calendar time, ethnicity, index of multiple deprivation rank, household deprivation, university degree, keyworker status, country of birth, main language, region, disability, and comorbidities. Interactions between variant and sex, age, vaccination status, and comorbidities were also investigated. RESULTS: The risk of covid-19 death was 66% lower (95% confidence interval 54% to 75%) for omicron BA.1 compared with delta after adjusting for a wide range of potential confounders. The reduction in the risk of covid-19 death for omicron compared with delta was more pronounced in people aged 18-59 years (number of deaths: delta=46, omicron=11; hazard ratio 0.14, 95% confidence interval 0.07 to 0.27) than in those aged ≥70 years (number of deaths: delta=113, omicron=135; hazard ratio 0.44, 95% confidence interval 0.32 to 0.61, P<0.0001). No evidence of a difference in risk was found between variant and number of comorbidities. CONCLUSIONS: The results support earlier studies showing a reduction in severity of infection with omicron BA.1 compared with delta in terms of hospital admission. This study extends the research to also show a reduction in the risk of covid-19 death for the omicron variant compared with the delta variant.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/mortality , COVID-19/virology , Humans , Proportional Hazards Models , Retrospective Studies , SARS-CoV-2/classification , SARS-CoV-2/pathogenicity
10.
J Virol ; 96(15): e0055822, 2022 08 10.
Article in English | MEDLINE | ID: covidwho-1962090

ABSTRACT

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, several variants of concern (VOCs) have arisen which are defined by multiple mutations in their spike proteins. These VOCs have shown variable escape from antibody responses and have been shown to trigger qualitatively different antibody responses during infection. By studying plasma from individuals infected with either the original D614G, Beta, or Delta variants, we showed that the Beta and Delta variants elicit antibody responses that are overall more cross-reactive than those triggered by D614G. Patterns of cross-reactivity varied, and the Beta and Delta variants did not elicit cross-reactive responses to each other. However, Beta-elicited plasma was highly cross-reactive against Delta Plus (Delta+), which differs from Delta by a single K417N mutation in the receptor binding domain, suggesting that the plasma response targets the N417 residue. To probe this further, we isolated monoclonal antibodies from a Beta-infected individual with plasma responses against Beta, Delta+, and Omicron, which all possess the N417 residue. We isolated an N417-dependent antibody, 084-7D, which showed similar neutralization breadth to the plasma. The 084-7D MAb utilized the IGHV3-23*01 germ line gene and had somatic hypermutations similar to those of previously described public antibodies which target the 417 residue. Thus, we have identified a novel antibody which targets a shared epitope found on three distinct VOCs, enabling their cross-neutralization. Understanding antibodies targeting escape mutations, such as K417N, which repeatedly emerge through convergent evolution in SARS-CoV-2 variants, may aid in the development of next-generation antibody therapeutics and vaccines. IMPORTANCE The evolution of SARS-CoV-2 has resulted in variants of concern (VOCs) with distinct spike mutations conferring various immune escape profiles. These variable mutations also influence the cross-reactivity of the antibody response mounted by individuals infected with each of these variants. This study sought to understand the antibody responses elicited by different SARS-CoV-2 variants and to define shared epitopes. We show that Beta and Delta infections resulted in antibody responses that were more cross-reactive than the original D614G variant, but they had differing patterns of cross-reactivity. We further isolated an antibody from Beta infection which targeted the N417 site, enabling cross-neutralization of Beta, Delta+, and Omicron, all of which possess this residue. The discovery of antibodies which target escape mutations common to multiple variants highlights conserved epitopes to target in future vaccines and therapeutics.


Subject(s)
Antibodies, Viral , Cross Reactions , Epitopes , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/virology , Cross Reactions/immunology , Epitopes/chemistry , Epitopes/genetics , Epitopes/immunology , Humans , Immune Evasion/immunology , Neutralization Tests , SARS-CoV-2/chemistry , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
11.
Science ; 377(6609): 960-966, 2022 08 26.
Article in English | MEDLINE | ID: covidwho-1962060

ABSTRACT

Understanding the circumstances that lead to pandemics is important for their prevention. We analyzed the genomic diversity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) early in the coronavirus disease 2019 (COVID-19) pandemic. We show that SARS-CoV-2 genomic diversity before February 2020 likely comprised only two distinct viral lineages, denoted "A" and "B." Phylodynamic rooting methods, coupled with epidemic simulations, reveal that these lineages were the result of at least two separate cross-species transmission events into humans. The first zoonotic transmission likely involved lineage B viruses around 18 November 2019 (23 October to 8 December), and the separate introduction of lineage A likely occurred within weeks of this event. These findings indicate that it is unlikely that SARS-CoV-2 circulated widely in humans before November 2019 and define the narrow window between when SARS-CoV-2 first jumped into humans and when the first cases of COVID-19 were reported. As with other coronaviruses, SARS-CoV-2 emergence likely resulted from multiple zoonotic events.


Subject(s)
COVID-19 , Pandemics , SARS-CoV-2 , Viral Zoonoses , Animals , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Computer Simulation , Genetic Variation , Genomics/methods , Humans , Molecular Epidemiology , Phylogeny , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Zoonoses/epidemiology , Viral Zoonoses/virology
12.
J Virol ; 96(15): e0095822, 2022 08 10.
Article in English | MEDLINE | ID: covidwho-1949998

ABSTRACT

The spike protein on sarbecovirus virions contains two external, protruding domains: an N-terminal domain (NTD) with unclear function and a C-terminal domain (CTD) that binds the host receptor, allowing for viral entry and infection. While the CTD is well studied for therapeutic interventions, the role of the NTD is far less well understood for many coronaviruses. Here, we demonstrate that the spike NTD from SARS-CoV-2 and other sarbecoviruses binds to unidentified glycans in vitro similarly to other members of the Coronaviridae family. We also show that these spike NTD (S-NTD) proteins adhere to Calu3 cells, a human lung cell line, although the biological relevance of this is unclear. In contrast to what has been shown for Middle East respiratory syndrome coronavirus (MERS-CoV), which attaches sialic acids during cell entry, sialic acids present on Calu3 cells inhibited sarbecovirus infection. Therefore, while sarbecoviruses can interact with cell surface glycans similarly to other coronaviruses, their reliance on glycans for entry is different from that of other respiratory coronaviruses, suggesting sarbecoviruses and MERS-CoV have adapted to different cell types, tissues, or hosts during their divergent evolution. Our findings provide important clues for further exploring the biological functions of sarbecovirus glycan binding and adds to our growing understanding of the complex forces that shape coronavirus spike evolution. IMPORTANCE Spike N-terminal domains (S-NTD) of sarbecoviruses are highly diverse; however, their function remains largely understudied compared with the receptor-binding domains (RBD). Here, we show that sarbecovirus S-NTD can be phylogenetically clustered into five clades and exhibit various levels of glycan binding in vitro. We also show that, unlike some coronaviruses, including MERS-CoV, sialic acids present on the surface of Calu3, a human lung cell culture, inhibit SARS-CoV-2 and other sarbecoviruses. These results suggest that while glycan binding might be an ancestral trait conserved across different coronavirus families, the functional outcome during infection can vary, reflecting divergent viral evolution. Our results expand our knowledge on the biological functions of the S-NTD across diverse sarbecoviruses and provide insight on the evolutionary history of coronavirus spike.


Subject(s)
Evolution, Molecular , Middle East Respiratory Syndrome Coronavirus , Polysaccharides , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , COVID-19/virology , Cell Line , Humans , Middle East Respiratory Syndrome Coronavirus/chemistry , Middle East Respiratory Syndrome Coronavirus/classification , Middle East Respiratory Syndrome Coronavirus/metabolism , Polysaccharides/metabolism , Protein Domains , Receptors, Virus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/classification , SARS-CoV-2/metabolism , Sialic Acids/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
13.
J Virol ; 96(15): e0068922, 2022 08 10.
Article in English | MEDLINE | ID: covidwho-1949995

ABSTRACT

Vaccines targeting SARS-CoV-2 have been shown to be highly effective; however, the breadth against emerging variants and the longevity of protection remains unclear. Postimmunization boosting has been shown to be beneficial for disease protection, and as new variants continue to emerge, periodic (and perhaps annual) vaccination will likely be recommended. New seasonal influenza virus vaccines currently need to be developed every year due to continual antigenic drift, an undertaking made possible by a robust global vaccine production and distribution infrastructure. To create a seasonal combination vaccine targeting both influenza viruses and SARS-CoV-2 that is also amenable to frequent reformulation, we have developed an influenza A virus (IAV) genetic platform that allows the incorporation of an immunogenic domain of the SARS-CoV-2 spike (S) protein onto IAV particles. Vaccination with this combination vaccine elicited neutralizing antibodies and provided protection from lethal challenge with both pathogens in mice. This approach may allow the leveraging of established influenza vaccine infrastructure to generate a cost-effective and scalable seasonal vaccine solution for both influenza and coronaviruses. IMPORTANCE The rapid emergence of SARS-CoV-2 variants since the onset of the pandemic has highlighted the need for both periodic vaccination "boosts" and a platform that can be rapidly reformulated to manufacture new vaccines. In this work, we report an approach that can utilize current influenza vaccine manufacturing infrastructure to generate combination vaccines capable of protecting from both influenza virus- and SARS-CoV-2-induced disease. The production of a combined influenza/SARS-CoV-2 vaccine may represent a practical solution to boost immunity to these important respiratory viruses without the increased cost and administration burden of multiple independent vaccines.


Subject(s)
COVID-19 Vaccines , COVID-19 , Influenza A virus , Influenza Vaccines , Orthomyxoviridae Infections , SARS-CoV-2 , Vaccines, Combined , Virion , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Humans , Influenza A virus/immunology , Influenza Vaccines/administration & dosage , Influenza Vaccines/immunology , Influenza, Human/immunology , Influenza, Human/prevention & control , Mice , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , SARS-CoV-2/classification , SARS-CoV-2/immunology , Vaccines, Combined/administration & dosage , Vaccines, Combined/immunology
14.
Nature ; 608(7923): 603-608, 2022 08.
Article in English | MEDLINE | ID: covidwho-1921637

ABSTRACT

SARS-CoV-2 Omicron subvariants BA.2.12.1 and BA.4/5 have surged notably to become dominant in the United States and South Africa, respectively1,2. These new subvariants carrying further mutations in their spike proteins raise concerns that they may further evade neutralizing antibodies, thereby further compromising the efficacy of COVID-19 vaccines and therapeutic monoclonals. We now report findings from a systematic antigenic analysis of these surging Omicron subvariants. BA.2.12.1 is only modestly (1.8-fold) more resistant to sera from vaccinated and boosted individuals than BA.2. However, BA.4/5 is substantially (4.2-fold) more resistant and thus more likely to lead to vaccine breakthrough infections. Mutation at spike residue L452 found in both BA.2.12.1 and BA.4/5 facilitates escape from some antibodies directed to the so-called class 2 and 3 regions of the receptor-binding domain3. The F486V mutation found in BA.4/5 facilitates escape from certain class 1 and 2 antibodies but compromises the spike affinity for the viral receptor. The R493Q reversion mutation, however, restores receptor affinity and consequently the fitness of BA.4/5. Among therapeutic antibodies authorized for clinical use, only bebtelovimab retains full potency against both BA.2.12.1 and BA.4/5. The Omicron lineage of SARS-CoV-2 continues to evolve, successively yielding subvariants that are not only more transmissible but also more evasive to antibodies.


Subject(s)
Antibodies, Viral , Antigenic Drift and Shift , COVID-19 , Mutation , SARS-CoV-2 , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , Antigenic Drift and Shift/genetics , Antigenic Drift and Shift/immunology , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Humans , Immunization, Secondary , Receptors, Virus/metabolism , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
15.
Nature ; 609(7925): 101-108, 2022 09.
Article in English | MEDLINE | ID: covidwho-1921636

ABSTRACT

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing and/or sequencing capacity, which can also introduce biases1-3. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing4,5. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We developed and deployed improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detected emerging variants of concern up to 14 days earlier in wastewater samples, and identified multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.


Subject(s)
COVID-19 , SARS-CoV-2 , Waste Water , Wastewater-Based Epidemiological Monitoring , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Humans , RNA, Viral/analysis , RNA, Viral/genetics , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Sequence Analysis, RNA , Waste Water/virology
17.
J Chem Theory Comput ; 17(12): 7972-7979, 2021 Dec 14.
Article in English | MEDLINE | ID: covidwho-1908075

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the current coronavirus disease 2019 (COVID-19) pandemic. It is known that the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 interacts with the human angiotensin-converting enzyme 2 (ACE2) receptor, initiating the entry of SARS-CoV-2. Since its emergence, a number of SARS-CoV-2 variants have been reported, and the variants that show high infectivity are classified as variants of concern according to the United States Centers for Disease Control and Prevention. In this study, we performed both all-atom steered molecular dynamics (SMD) simulations and microscale thermophoresis (MST) experiments to characterize the binding interactions between ACE2 and RBD of all current variants of concern (Alpha, Beta, Gamma, and Delta) and two variants of interest (Epsilon and Kappa). We report that RBD of the Alpha (N501Y) variant requires the highest amount of force initially to be detached from ACE2 due to the N501Y mutation in addition to the role of N90-glycan, followed by Beta/Gamma (K417N/T, E484 K, and N501Y) or Delta (L452R and T478 K) variants. Among all variants investigated in this work, RBD of the Epsilon (L452R) variant is relatively easily detached from ACE2. Our results from both SMD simulations and MST experiments indicate what makes each variant more contagious in terms of RBD and ACE2 interactions. This study could shed light on developing new drugs to inhibit SARS-CoV-2 entry effectively.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/virology , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , COVID-19/metabolism , HEK293 Cells , Humans , Protein Binding , SARS-CoV-2/classification , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Virus Internalization
18.
Nature ; 608(7923): 593-602, 2022 08.
Article in English | MEDLINE | ID: covidwho-1900499

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages BA.2.12.1, BA.4 and BA.5 exhibit higher transmissibility than the BA.2 lineage1. The receptor binding and immune-evasion capability of these recently emerged variants require immediate investigation. Here, coupled with structural comparisons of the spike proteins, we show that BA.2.12.1, BA.4 and BA.5 (BA.4 and BA.5 are hereafter referred collectively to as BA.4/BA.5) exhibit similar binding affinities to BA.2 for the angiotensin-converting enzyme 2 (ACE2) receptor. Of note, BA.2.12.1 and BA.4/BA.5 display increased evasion of neutralizing antibodies compared with BA.2 against plasma from triple-vaccinated individuals or from individuals who developed a BA.1 infection after vaccination. To delineate the underlying antibody-evasion mechanism, we determined the escape mutation profiles2, epitope distribution3 and Omicron-neutralization efficiency of 1,640 neutralizing antibodies directed against the receptor-binding domain of the viral spike protein, including 614 antibodies isolated from people who had recovered from BA.1 infection. BA.1 infection after vaccination predominantly recalls humoral immune memory directed against ancestral (hereafter referred to as wild-type (WT)) SARS-CoV-2 spike protein. The resulting elicited antibodies could neutralize both WT SARS-CoV-2 and BA.1 and are enriched on epitopes on spike that do not bind ACE2. However, most of these cross-reactive neutralizing antibodies are evaded by spike mutants L452Q, L452R and F486V. BA.1 infection can also induce new clones of BA.1-specific antibodies that potently neutralize BA.1. Nevertheless, these neutralizing antibodies are largely evaded by BA.2 and BA.4/BA.5 owing to D405N and F486V mutations, and react weakly to pre-Omicron variants, exhibiting narrow neutralization breadths. The therapeutic neutralizing antibodies bebtelovimab4 and cilgavimab5 can effectively neutralize BA.2.12.1 and BA.4/BA.5, whereas the S371F, D405N and R408S mutations undermine most broadly sarbecovirus-neutralizing antibodies. Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.


Subject(s)
Antibodies, Viral , Antigenic Drift and Shift , COVID-19 , Epitopes, B-Lymphocyte , Immune Tolerance , Mutation , SARS-CoV-2 , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigenic Drift and Shift/genetics , Antigenic Drift and Shift/immunology , COVID-19/immunology , COVID-19/transmission , COVID-19/virology , COVID-19 Vaccines/immunology , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/genetics , Epitopes, B-Lymphocyte/immunology , Humans , Immunity, Humoral , Immunization, Secondary , Neutralization Tests , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
19.
Nature ; 606(7914): 452-455, 2022 06.
Article in English | MEDLINE | ID: covidwho-1890140
20.
Nat Biomed Eng ; 6(8): 932-943, 2022 08.
Article in English | MEDLINE | ID: covidwho-1873504

ABSTRACT

The widespread transmission and evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) call for rapid nucleic acid diagnostics that are easy to use outside of centralized clinical laboratories. Here we report the development and performance benchmarking of Cas13-based nucleic acid assays leveraging lyophilised reagents and fast sample inactivation at ambient temperature. The assays, which we named SHINEv.2 (for 'streamlined highlighting of infections to navigate epidemics, version 2'), simplify the previously reported RNA-extraction-free SHINEv.1 technology by eliminating heating steps and the need for cold storage of the reagents. SHINEv.2 detected SARS-CoV-2 in nasopharyngeal samples with 90.5% sensitivity and 100% specificity (benchmarked against the reverse transcription quantitative polymerase chain reaction) in less than 90 min, using lateral-flow technology and incubation in a heat block at 37 °C. SHINEv.2 also allows for the visual discrimination of the Alpha, Beta, Gamma, Delta and Omicron SARS-CoV-2 variants, and can be run without performance losses by using body heat. Accurate, easy-to-use and equipment-free nucleic acid assays could facilitate wider testing for SARS-CoV-2 and other pathogens in point-of-care and at-home settings.


Subject(s)
COVID-19 , Nucleic Acids , COVID-19/diagnosis , COVID-19/virology , COVID-19 Testing , CRISPR-Associated Proteins , Humans , SARS-CoV-2/classification , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification
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