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1.
Vaccines ; 10(5):696, 2022.
Article in English | MDPI | ID: covidwho-1820436

ABSTRACT

In order to longitudinally track SARS-CoV-2 antibody levels after vaccination or infection, we assessed anti-RBD antibody levels in over 1000 people and found no significant decrease in antibody levels during the first 14 months after infection in unvaccinated participants, however, a significant waning of antibody levels was observed following vaccination. Participants who were pre-immune to SARS-CoV-2 prior to vaccination seroconverted to higher antibody levels, which were maintained at higher levels than in previously infected, unvaccinated participants. Older participants exhibited lower level of antibodies after vaccination, but a higher level after infection than younger people. The rate of antibody waning was not affected by pre-immunity or age. Participants who received a third dose of an mRNA vaccine not only increased their antibody levels ~14-fold, but also had ~3 times more antibodies compared to when they received their primary vaccine series. PBMC-derived memory B cells from 13 participants who lost all circulating antibodies were differentiated into antibody secreting cells (ASCs). There was a significant recall of memory B cell ASCs in the absence of serum antibodies in 5–8 of the 10 vaccinated participants, but not in any of the 3 infected participants, suggesting a strong connection between antibody levels and the effectiveness of memory B cell recall.

2.
J Virol ; 96(5): e0179121, 2022 03 09.
Article in English | MEDLINE | ID: covidwho-1799229

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and seasonal influenza viruses are cocirculating in the human population. However, only a few cases of viral coinfection with these two viruses have been documented in humans with some people having severe disease and others mild disease. To examine this phenomenon, ferrets were coinfected with SARS-CoV-2 and human seasonal influenza A viruses (IAVs; H1N1 or H3N2) and were compared to animals that received each virus alone. Ferrets were either immunologically naive to both viruses or vaccinated with the 2019 to 2020 split-inactivated influenza virus vaccine. Coinfected naive ferrets lost significantly more body weight than ferrets infected with each virus alone and had more severe inflammation in both the nose and lungs compared to that of ferrets that were single infected with each virus. Coinfected, naive animals had predominantly higher IAV titers than SARS-CoV-2 titers, and IAVs were efficiently transmitted by direct contact to the cohoused ferrets. Comparatively, SARS-CoV-2 failed to transmit to the ferrets that cohoused with coinfected ferrets by direct contact. Moreover, vaccination significantly reduced IAV titers and shortened the viral shedding but did not completely block direct contact transmission of the influenza virus. Notably, vaccination significantly ameliorated influenza-associated disease by protecting vaccinated animals from severe morbidity after IAV single infection or IAV and SARS-CoV-2 coinfection, suggesting that seasonal influenza virus vaccination is pivotal to prevent severe disease induced by IAV and SARS-CoV-2 coinfection during the COVID-19 pandemic. IMPORTANCE Influenza A viruses cause severe morbidity and mortality during each influenza virus season. The emergence of SARS-CoV-2 infection in the human population offers the opportunity to potential coinfections of both viruses. The development of useful animal models to assess the pathogenesis, transmission, and viral evolution of these viruses as they coinfect a host is of critical importance for the development of vaccines and therapeutics. The ability to prevent the most severe effects of viral coinfections can be studied using effect coinfection ferret models described in this report.


Subject(s)
Antibodies, Viral/blood , COVID-19/prevention & control , Coinfection/prevention & control , Influenza Vaccines/immunology , Orthomyxoviridae Infections/prevention & control , Animals , COVID-19/immunology , Female , Ferrets/immunology , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/immunology , Orthomyxoviridae Infections/immunology , Vaccination , Virus Shedding
3.
Sci Rep ; 12(1): 3480, 2022 03 03.
Article in English | MEDLINE | ID: covidwho-1730307

ABSTRACT

The COVID-19 pandemic has resulted in significant diversion of human and material resources to COVID-19 diagnostics, to the extent that influenza viruses and co-infection in COVID-19 patients remains undocumented and pose serious public-health consequences. We optimized and validated a highly sensitive RT-PCR based multiplex-assay for the detection of SARS-CoV-2, influenza A and B viruses in a single-test. This study evaluated clinical specimens (n = 1411), 1019 saliva and 392 nasopharyngeal swab (NPS), tested using two-assays: FDA-EUA approved SARS-CoV-2 assay that targets N and ORF1ab gene, and the PKamp-RT-PCR based assay that targets SARS-CoV-2, influenza viruses A and B. Of the 1019 saliva samples, 17.0% (174/1019) tested positive for SARS-CoV-2 using either assay. The detection rate for SARS-CoV-2 was higher with the multiplex assay compared to SARS-specific assay [91.9% (160/174) vs. 87.9% (153/174)], respectively. Of the 392 NPS samples, 10.4% (41/392) tested positive for SARS-CoV-2 using either assay. The detection rate for SARS-CoV-2 was higher with the multiplex assay compared to SARS-specific assay [97.5% (40/41) vs. 92.1% (39/41)], respectively. This study presents clinical validation of a multiplex-PCR assay for testing SARS-CoV-2, influenza A and B viruses, using NPS and saliva samples, and demonstrates the feasibility of implementing the assay without disrupting the existing laboratory workflow.


Subject(s)
Influenza A virus/isolation & purification , Influenza B virus/isolation & purification , Multiplex Polymerase Chain Reaction/methods , Nasopharynx/virology , SARS-CoV-2/isolation & purification , Saliva/virology , Humans , Limit of Detection , Reproducibility of Results
4.
EBioMedicine ; 74: 103748, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1568650

ABSTRACT

BACKGROUND: Limited knowledge exists regarding antibody affinity maturation following mRNA vaccination in naïve vs. COVID-19 recovered individuals and potential sex differences. METHODS: We elucidated post-vaccination antibody profiles of 69 naïve and 17 COVID-19 convalescent adults using pseudovirus neutralization assay (PsVNA) covering SARS-CoV-2 WA-1, variants of concern (VOCs) and variants of interest (VOIs). Surface Plasmon Resonance (SPR) was used to measure antibody affinity against prefusion spike and receptor binding domain (RBD) and RBD mutants. FINDINGS: Higher neutralizing antibodies were observed in convalescent vs. naïve adults against, WA-1, VOCs, and VOIs. Antibody binding to RBD and RBD mutants showed lower binding of post-vaccination sera from naïve compared with convalescent individuals. Moreover, we observed early antibody affinity maturation in convalescent individuals after one vaccine dose and higher antibody affinity after two doses compared with the naïve group. Among the naïve participants, antibody affinity against the SARS-CoV-2 prefusion spike was significantly higher for males than females even though there were no difference in neutralization titers between sexes. INTERPRETATION: This study demonstrates the impact of prior infection on vaccine-induced antibody affinity maturation and difference in antibody affinity between males and females. Further studies are needed to determine whether antibody affinity may contribute to correlates of protection against SARS-CoV-2 and its variants. FUNDING: The antibody characterization work described in this manuscript was supported by FDA's Medical Countermeasures Initiative (MCMi) grant #OCET 2021-1565 to S.K and intramural FDA-CBER COVID-19 supplemental funds. The SPARTA program was supported by the National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Department of Health and Human Services contract 75N93019C00052, and the University of Georgia (US) grant UGA-001. T.M.R is also supported by the Georgia Research Alliance (US) grant GRA-001. The CTRU was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR002378.


Subject(s)
/immunology , Antibodies, Neutralizing/blood , Antibody Affinity/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Viral/blood , COVID-19/immunology , Cell Line , Female , Humans , Male , Neutralization Tests , Protein Domains/immunology , Surface Plasmon Resonance , Vaccination , /immunology
5.
J Clin Invest ; 131(13)2021 07 01.
Article in English | MEDLINE | ID: covidwho-1556620

ABSTRACT

Seasonal influenza vaccination elicits a diminished adaptive immune response in the elderly, and the mechanisms of immunosenescence are not fully understood. Using Ig-Seq, we found a marked increase with age in the prevalence of cross-reactive (CR) serum antibodies that recognize both the H1N1 (vaccine-H1) and H3N2 (vaccine-H3) components of an egg-produced split influenza vaccine. CR antibodies accounted for 73% ± 18% of the serum vaccine responses in a cohort of elderly donors, 65% ± 15% in late middle-aged donors, and only 13% ± 5% in persons under 35 years of age. The antibody response to non-HA antigens was boosted by vaccination. Recombinant expression of 19 vaccine-H1+H3 CR serum monoclonal antibodies (s-mAbs) revealed that they predominantly bound to non-HA influenza proteins. A sizable fraction of vaccine-H1+H3 CR s-mAbs recognized with high affinity the sulfated glycans, in particular sulfated type 2 N-acetyllactosamine (Galß1-4GalNAcß), which is found on egg-produced proteins and thus unlikely to contribute to protection against influenza infection in humans. Antibodies against sulfated glycans in egg-produced vaccine had been identified in animals but were not previously characterized in humans. Collectively, our results provide a quantitative basis for how repeated exposure to split influenza vaccine correlates with unintended focusing of serum antibody responses to non-HA antigens that may result in suboptimal immunity against influenza.


Subject(s)
Antibodies, Viral/biosynthesis , Influenza Vaccines/immunology , Influenza, Human/immunology , Viral Proteins/immunology , Adult , Age Factors , Aged , Animals , Antibodies, Monoclonal/immunology , Antibodies, Viral/blood , Cohort Studies , Cross Reactions , Eggs/analysis , Humans , Immunoglobulin G/biosynthesis , Immunoglobulin G/blood , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H3N2 Subtype/immunology , Influenza, Human/prevention & control , Influenza, Human/virology , Middle Aged , Polysaccharides/immunology , Vaccination
6.
Front Immunol ; 12: 728021, 2021.
Article in English | MEDLINE | ID: covidwho-1538370

ABSTRACT

As the COVID-19 pandemic continues, the authorization of vaccines for emergency use has been crucial in slowing down the rate of infection and transmission of the SARS-CoV-2 virus that causes COVID-19. In order to investigate the longitudinal serological responses to SARS-CoV-2 natural infection and vaccination, a large-scale, multi-year serosurveillance program entitled SPARTA (SARS SeroPrevalence and Respiratory Tract Assessment) was initiated at 4 locations in the U.S. The serological assay presented here measuring IgG binding to the SARS-CoV-2 receptor binding domain (RBD) detected antibodies elicited by SARS-CoV-2 infection or vaccination with a 95.5% sensitivity and a 95.9% specificity. We used this assay to screen more than 3100 participants and selected 20 previously infected pre-immune and 32 immunologically naïve participants to analyze their antibody binding to RBD and viral neutralization (VN) responses following vaccination with two doses of either the Pfizer-BioNTech BNT162b2 or the Moderna mRNA-1273 vaccine. Vaccination not only elicited a more robust immune reaction than natural infection, but the level of neutralizing and anti-RBD antibody binding after vaccination is also significantly higher in pre-immune participants compared to immunologically naïve participants (p<0.0033). Furthermore, the administration of the second vaccination did not further increase the neutralizing or binding antibody levels in pre-immune participants (p=0.69). However, ~46% of the immunologically naïve participants required both vaccinations to seroconvert.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Immunogenicity, Vaccine , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing , COVID-19 Vaccines/immunology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Time Factors , United States , Young Adult
7.
Viruses ; 13(10)2021 10 14.
Article in English | MEDLINE | ID: covidwho-1470994

ABSTRACT

Two serious public health challenges have emerged in the current COVID-19 pandemic namely, deficits in SARS-CoV-2 variant monitoring and neglect of other co-circulating respiratory viruses. Additionally, accurate assessment of the evolution, extent, and dynamics of the outbreak is required to understand the transmission of the virus. To address these challenges, we evaluated 533 samples using a high-throughput next-generation sequencing (NGS) respiratory viral panel (RVP) that includes 40 viral pathogens. The performance metrics revealed a PPA, NPA, and accuracy of 95.98%, 85.96%, and 94.4%, respectively. The clade for pangolin lineage B that contains certain distant variants, including P4715L in ORF1ab, Q57H in ORF3a, and S84L in ORF8 covarying with the D614G spike protein mutation, were the most prevalent early in the pandemic in Georgia, USA. The isolates from the same county formed paraphyletic groups, indicating virus transmission between counties. The study demonstrates the clinical and public health utility of the NGS-RVP to identify novel variants that can provide actionable information to prevent or mitigate emerging viral threats and models that provide insights into viral transmission patterns and predict transmission/resurgence of regional outbreaks as well as providing critical information on co-circulating respiratory viruses that might be independent factors contributing to the global disease burden.


Subject(s)
COVID-19/epidemiology , Genome, Viral/genetics , Respiratory Tract Infections/diagnosis , Respiratory Tract Infections/virology , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/transmission , High-Throughput Nucleotide Sequencing , Humans , Limit of Detection , Phylogeny , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics
8.
Front Immunol ; 12: 728021, 2021.
Article in English | MEDLINE | ID: covidwho-1468342

ABSTRACT

As the COVID-19 pandemic continues, the authorization of vaccines for emergency use has been crucial in slowing down the rate of infection and transmission of the SARS-CoV-2 virus that causes COVID-19. In order to investigate the longitudinal serological responses to SARS-CoV-2 natural infection and vaccination, a large-scale, multi-year serosurveillance program entitled SPARTA (SARS SeroPrevalence and Respiratory Tract Assessment) was initiated at 4 locations in the U.S. The serological assay presented here measuring IgG binding to the SARS-CoV-2 receptor binding domain (RBD) detected antibodies elicited by SARS-CoV-2 infection or vaccination with a 95.5% sensitivity and a 95.9% specificity. We used this assay to screen more than 3100 participants and selected 20 previously infected pre-immune and 32 immunologically naïve participants to analyze their antibody binding to RBD and viral neutralization (VN) responses following vaccination with two doses of either the Pfizer-BioNTech BNT162b2 or the Moderna mRNA-1273 vaccine. Vaccination not only elicited a more robust immune reaction than natural infection, but the level of neutralizing and anti-RBD antibody binding after vaccination is also significantly higher in pre-immune participants compared to immunologically naïve participants (p<0.0033). Furthermore, the administration of the second vaccination did not further increase the neutralizing or binding antibody levels in pre-immune participants (p=0.69). However, ~46% of the immunologically naïve participants required both vaccinations to seroconvert.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Immunogenicity, Vaccine , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing , COVID-19 Vaccines/immunology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Time Factors , United States , Young Adult
9.
Vaccine ; 39(40): 5940-5953, 2021 09 24.
Article in English | MEDLINE | ID: covidwho-1336992

ABSTRACT

The development of a safe and effective vaccine is a key requirement to overcoming the COVID-19 pandemic. Recombinant proteins represent the most reliable and safe vaccine approach but generally require a suitable adjuvant for robust and durable immunity. We used the SARS-CoV-2 genomic sequence and in silico structural modelling to design a recombinant spike protein vaccine (Covax-19™). A synthetic gene encoding the spike extracellular domain (ECD) was inserted into a baculovirus backbone to express the protein in insect cell cultures. The spike ECD was formulated with Advax-SM adjuvant and first tested for immunogenicity in C57BL/6 and BALB/c mice. Covax-19 vaccine induced high spike protein binding antibody levels that neutralised the original lineage B.1.319 virus from which the vaccine spike protein was derived, as well as the variant B.1.1.7 lineage virus. Covax-19 vaccine also induced a high frequency of spike-specific CD4 + and CD8 + memory T-cells with a dominant Th1 phenotype associated with the ability to kill spike-labelled target cells in vivo. Ferrets immunised with Covax-19 vaccine intramuscularly twice 2 weeks apart made spike receptor binding domain (RBD) IgG and were protected against an intranasal challenge with SARS-CoV-2 virus given two weeks after the last immunisation. Notably, ferrets that received the two higher doses of Covax-19 vaccine had no detectable virus in their lungs or in nasal washes at day 3 post-challenge, suggesting that in addition to lung protection, Covax-19 vaccine may have the potential to reduce virus transmission. This data supports advancement of Covax-19 vaccine into human clinical trials.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Animals , Antibodies, Viral , Ferrets , Humans , Immunization , Inulin/analogs & derivatives , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Pandemics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics
10.
Cells ; 10(8)2021 07 21.
Article in English | MEDLINE | ID: covidwho-1325606

ABSTRACT

Assessment of humoral immunity to SARS-CoV-2 and other infectious agents is typically restricted to detecting antigen-specific antibodies in the serum. Rarely does immune monitoring entail assessment of the memory B-cell compartment itself, although it is these cells that engage in secondary antibody responses capable of mediating immune protection when pre-existing antibodies fail to prevent re-infection. There are few techniques that are capable of detecting rare antigen-specific B cells while also providing information regarding their relative abundance, class/subclass usage and functional affinity. In theory, the ELISPOT/FluoroSpot (collectively ImmunoSpot) assay platform is ideally suited for antigen-specific B-cell assessments since it provides this information at single-cell resolution for individual antibody-secreting cells (ASC). Here, we tested the hypothesis that antigen-coating efficiency could be universally improved across a diverse set of viral antigens if the standard direct (non-specific, low affinity) antigen absorption to the membrane was substituted by high-affinity capture. Specifically, we report an enhancement in assay sensitivity and a reduction in required protein concentrations through the capture of recombinant proteins via their encoded hexahistidine (6XHis) affinity tag. Affinity tag antigen coating enabled detection of SARS-CoV-2 Spike receptor binding domain (RBD)-reactive ASC, and also significantly improved assay performance using additional control antigens. Collectively, establishment of a universal antigen-coating approach streamlines characterization of the memory B-cell compartment after SARS-CoV-2 infection or COVID-19 vaccinations, and facilitates high-throughput immune-monitoring efforts of large donor cohorts in general.


Subject(s)
Antigens, Viral/analysis , B-Lymphocytes/immunology , Enzyme-Linked Immunospot Assay/methods , Immunologic Memory , SARS-CoV-2/immunology , Viral Proteins/immunology , Animals , COVID-19 , Histidine , Humans , Mice , Oligopeptides , SARS-CoV-2/metabolism
11.
J Mol Diagn ; 23(7): 788-795, 2021 07.
Article in English | MEDLINE | ID: covidwho-1275505

ABSTRACT

The clinical performance of saliva compared with nasopharyngeal swabs (NPSs) has shown conflicting results in healthcare and community settings. In the present study, a total of 429 matched NPS and saliva sample pairs, collected in either healthcare or community setting, were evaluated. Phase-1 (protocol U) tested 240 matched NPS and saliva sample pairs; phase 2 (SalivaAll protocol) tested 189 matched NPS and saliva sample pairs, with an additional sample homogenization step before RNA extraction. A total of 85 saliva samples were evaluated with both protocols. In phase-1, 28.3% (68/240) samples tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from saliva, NPS, or both. The detection rate from saliva was lower compared with that from NPS samples (50.0% versus 89.7%). In phase-2, 50.2% (95/189) samples tested positive for SARS-CoV-2 from saliva, NPS, or both. The detection rate from saliva was higher compared with that from NPS samples (97.8% versus 78.9%). Of the 85 saliva samples evaluated with both protocols, the detection rate was 100% for samples tested with SalivaAll, and 36.7% with protocol U. The limit of detection with SalivaAll protocol was 20 to 60 copies/mL. The pooled testing approach demonstrated a 95% positive and 100% negative percentage agreement. This protocol for saliva samples results in higher sensitivity compared with NPS samples and breaks the barrier to using pooled saliva for SARS-CoV-2 testing.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Delivery of Health Care , Mass Screening/methods , Population Surveillance/methods , Residence Characteristics , SARS-CoV-2/genetics , Saliva/virology , COVID-19/epidemiology , COVID-19/virology , Diagnostic Tests, Routine/methods , Georgia/epidemiology , Humans , Limit of Detection , RNA, Viral/genetics , RNA, Viral/isolation & purification , Real-Time Polymerase Chain Reaction , Sensitivity and Specificity
12.
Diagnostics (Basel) ; 11(5)2021 May 19.
Article in English | MEDLINE | ID: covidwho-1234682

ABSTRACT

OBJECTIVES: Limitations of widespread current COVID-19 diagnostic testing exist in both the pre-analytical and analytical stages. To alleviate these limitations, we developed a universal saliva processing protocol (SalivaSTAT) that would enable an extraction-free RT-PCR test using commercially available RT-PCR kits. METHODS: We optimized saliva collection devices, heat-shock treatment, and homogenization. Saliva samples (879) previously tested using the FDA-EUA method were reevaluated with the optimized SalivaSTAT protocol using two widely available commercial RT-PCR kits. A five-sample pooling strategy was evaluated as per FDA guidelines. RESULTS: Saliva collection (done without any media) showed performance comparable to that of the FDA-EUA method. The SalivaSTAT protocol was optimized by incubating saliva samples at 95 °C for 30-min and homogenization, followed by RT-PCR assay. The clinical sample evaluation of 630 saliva samples using the SalivaSTAT protocol with PerkinElmer (600-samples) and CDC (30-samples) RT-PCR assay achieved positive (PPA) and negative percent agreements (NPAs) of 95.0% and 100%, respectively. The LoD was established as ~60-180 copies/mL by absolute quantification. Furthermore, a five-sample-pooling evaluation using 250 saliva samples achieved a PPA and NPA of 92% and 100%, respectively. CONCLUSION: We have optimized an extraction-free RT-PCR assay for saliva samples that demonstrates comparable performance to FDA-EUA assay (Extraction and RT-PCR).

13.
Sci Transl Med ; 13(579)2021 02 03.
Article in English | MEDLINE | ID: covidwho-1112312

ABSTRACT

Development of safe and effective COVID-19 vaccines is a global priority and the best hope for ending the COVID-19 pandemic. Remarkably, in less than 1 year, vaccines have been developed and shown to be efficacious and are already being deployed worldwide. Yet, many challenges remain. Immune senescence and comorbidities in aging populations and immune dysregulation in populations living in low-resource settings may impede vaccine effectiveness. Distribution of vaccines among these populations where vaccine access is historically low remains challenging. In this Review, we address these challenges and provide strategies for ensuring that vaccines are developed and deployed for those most vulnerable.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/virology , Disease Susceptibility , SARS-CoV-2/physiology , Animals , COVID-19 Vaccines/adverse effects , Disease Models, Animal , Humans , Phylogeny
14.
Cell ; 184(7): 1821-1835.e16, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-1095899

ABSTRACT

Human monoclonal antibodies are safe, preventive, and therapeutic tools that can be rapidly developed to help restore the massive health and economic disruption caused by the coronavirus disease 2019 (COVID-19) pandemic. By single-cell sorting 4,277 SARS-CoV-2 spike protein-specific memory B cells from 14 COVID-19 survivors, 453 neutralizing antibodies were identified. The most potent neutralizing antibodies recognized the spike protein receptor-binding domain, followed in potency by antibodies that recognize the S1 domain, the spike protein trimer, and the S2 subunit. Only 1.4% of them neutralized the authentic virus with a potency of 1-10 ng/mL. The most potent monoclonal antibody, engineered to reduce the risk of antibody-dependent enhancement and prolong half-life, neutralized the authentic wild-type virus and emerging variants containing D614G, E484K, and N501Y substitutions. Prophylactic and therapeutic efficacy in the hamster model was observed at 0.25 and 4 mg/kg respectively in absence of Fc functions.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antibodies, Neutralizing/administration & dosage , Antibodies, Viral/administration & dosage , B-Lymphocytes/immunology , COVID-19 , Convalescence , 3T3 Cells , Animals , Antibodies, Monoclonal/isolation & purification , Antibodies, Neutralizing/isolation & purification , Antibodies, Viral/isolation & purification , B-Lymphocytes/cytology , COVID-19/immunology , COVID-19/prevention & control , COVID-19/therapy , Chlorocebus aethiops , Disease Models, Animal , Female , HEK293 Cells , Humans , Immunoglobulin Fc Fragments/immunology , Male , Mice , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
15.
Cell ; 184(7): 1804-1820.e16, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-1084553

ABSTRACT

SARS-CoV-2 has caused the global COVID-19 pandemic. Although passively delivered neutralizing antibodies against SARS-CoV-2 show promise in clinical trials, their mechanism of action in vivo is incompletely understood. Here, we define correlates of protection of neutralizing human monoclonal antibodies (mAbs) in SARS-CoV-2-infected animals. Whereas Fc effector functions are dispensable when representative neutralizing mAbs are administered as prophylaxis, they are required for optimal protection as therapy. When given after infection, intact mAbs reduce SARS-CoV-2 burden and lung disease in mice and hamsters better than loss-of-function Fc variant mAbs. Fc engagement of neutralizing antibodies mitigates inflammation and improves respiratory mechanics, and transcriptional profiling suggests these phenotypes are associated with diminished innate immune signaling and preserved tissue repair. Immune cell depletions establish that neutralizing mAbs require monocytes and CD8+ T cells for optimal clinical and virological benefit. Thus, potently neutralizing mAbs utilize Fc effector functions during therapy to mitigate lung infection and disease.


Subject(s)
Antibodies, Monoclonal , Antibodies, Neutralizing , Antibodies, Viral , CD8-Positive T-Lymphocytes , COVID-19 , Immunoglobulin Fc Fragments/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , CD8-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/immunology , CHO Cells , COVID-19/immunology , COVID-19/therapy , Chlorocebus aethiops , Cricetulus , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , SARS-CoV-2/immunology , Vero Cells , Viral Load
16.
Vet Microbiol ; 251: 108907, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-1065646

ABSTRACT

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is a great concern on both public and veterinary health. Multiple studies showed that the SARS-CoV-2 can persist for few days in wet condition, but it has not been clear whether the virus can maintain the infectivity in dry condition. Thus, we measured the infectious titer of dried SARS-CoV-2 (104 pfu/25 µL droplet) at 0, 0.5, 1, 2, 3, 24, and 48 h. Strikingly, the dried SARS-CoV-2 virus did not lose the infectivity to Vero E6 cells for up to 48 h. Our findings warrants that the drying cannot replace the surface disinfection to prevent transmission via common vehicle or nosocomial infection. Future studies can apply our experimental setting to test the efficacy of diverse disinfecting procedures.


Subject(s)
Desiccation , Glass , Microbial Viability , SARS-CoV-2/physiology , Animals , COVID-19 , Cell Line , Chlorocebus aethiops , SARS-CoV-2/pathogenicity , Time Factors , Vero Cells , Virus Replication
17.
Science ; 370(6521): 1208-1214, 2020 12 04.
Article in English | MEDLINE | ID: covidwho-913668

ABSTRACT

We developed a de novo protein design strategy to swiftly engineer decoys for neutralizing pathogens that exploit extracellular host proteins to infect the cell. Our pipeline allowed the design, validation, and optimization of de novo human angiotensin-converting enzyme 2 (hACE2) decoys to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The best monovalent decoy, CTC-445.2, bound with low nanomolar affinity and high specificity to the receptor-binding domain (RBD) of the spike protein. Cryo-electron microscopy (cryo-EM) showed that the design is accurate and can simultaneously bind to all three RBDs of a single spike protein. Because the decoy replicates the spike protein target interface in hACE2, it is intrinsically resilient to viral mutational escape. A bivalent decoy, CTC-445.2d, showed ~10-fold improvement in binding. CTC-445.2d potently neutralized SARS-CoV-2 infection of cells in vitro, and a single intranasal prophylactic dose of decoy protected Syrian hamsters from a subsequent lethal SARS-CoV-2 challenge.


Subject(s)
Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Antiviral Agents/pharmacology , COVID-19/drug therapy , Receptors, Virus/antagonists & inhibitors , Recombinant Proteins/pharmacology , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Animals , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Cricetinae , Cryoelectron Microscopy , Directed Molecular Evolution/methods , Protein Binding , Protein Domains , Protein Engineering/methods , Recombinant Proteins/chemistry , Recombinant Proteins/therapeutic use , Spike Glycoprotein, Coronavirus/chemistry
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