A high-affinity #RBD-targeting #nanobody improves #fusion partner’s potency against #SARS-CoV-2 (PLOS Pathog., abstract)

[Source: PLOS Pathogens, full page: (LINK). Abstract, edited.]

OPEN ACCESS |  PEER-REVIEWED | RESEARCH ARTICLE

A high-affinity RBD-targeting nanobody improves fusion partner’s potency against SARS-CoV-2

Hebang Yao , Hongmin Cai , Tingting Li , Bingjie Zhou , Wenming Qin, Dimitri  Lavillette , Dianfan Li

Published: March 3, 2021 | DOI: https://doi.org/10.1371/journal.ppat.1009328 | This is an uncorrected proof.

Abstract

A key step to the SARS-CoV-2 infection is the attachment of its Spike receptor-binding domain (S RBD) to the host receptor ACE2. Considerable research has been devoted to the development of neutralizing antibodies, including llama-derived single-chain nanobodies, to target the receptor-binding motif (RBM) and to block ACE2-RBD binding. Simple and effective strategies to increase potency are desirable for such studies when antibodies are only modestly effective. Here, we identify and characterize a high-affinity synthetic nanobody (sybody, SR31) as a fusion partner to improve the potency of RBM-antibodies. Crystallographic studies reveal that SR31 binds to RBD at a conserved and ‘greasy’ site distal to RBM. Although SR31 distorts RBD at the interface, it does not perturb the RBM conformation, hence displaying no neutralizing activities itself. However, fusing SR31 to two modestly neutralizing sybodies dramatically increases their affinity for RBD and neutralization activity against SARS-CoV-2 pseudovirus. Our work presents a tool protein and an efficient strategy to improve nanobody potency.

Author summary

SARS-CoV-2 relies on the receptor-binding domain (RBD) of its envelope Spike protein to recognize and infect host cells. RBD is therefore an immunological hotspot to generate antibodies for therapeutic and detection purposes. Binding affinity is one of the key characteristics of such antibodies. Here, we report a single-chain antibody (nanobody, ~14 kDa) that binds RBD with nanomolar affinity. The nanobody, dubbed SR31, binds RBD at an epitope distal to the receptor-binding motif (RBM) which is the target of most neutralizing antibodies. SR31 can therefore bind RBD in addition to RMB-binders, and increase their affinity and potency by avidity effects when used as a fusion partner. Compared to other in vitro affinity maturation techniques such as library screening and structure-based design, the fusion strategy offers advantages in speed and simplicity. In addition, SR31, together with RBD-targeting nanobodies recognizing a wide spectrum of epitopes, provides a useful toolkit to probe epitopes of uncharacterized antibodies by competitive binding.

Citation: Yao H, Cai H, Li T, Zhou B, Qin W, Lavillette D, et al. (2021) A high-affinity RBD-targeting nanobody improves fusion partner’s potency against SARS-CoV-2. PLoS Pathog 17(3): e1009328. https://doi.org/10.1371/journal.ppat.1009328

Editor: Ron A. M. Fouchier, Erasmus Medical Center, NETHERLANDS

Received: September 23, 2020; Accepted: January 21, 2021; Published: March 3, 2021

Copyright: © 2021 Yao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The structure factors and coordinates were deposited in the protein data bank (PDB) under accession codes 7D2Z (SR31+RBD) and 7D30 (MR17-SR31+RBD)

Funding: This work has been supported by the Strategic Priority Research Program of CAS (XDB37020204), Key Program of CAS Frontier Science (QYZDB SSW-SMC037), CAS Facility based Open Research Program, the National Natural Science Foundation of China (31870726, D.Li; 31870153, D.La.), Ministry of Science and Technology of China (2020YFC0845900), CAS president’s international fellowship initiative (2020VBA0023), the Key R & D Program of Jiangsu Province (Social Development) Project (BE2019625), Shanghai Municipal Science and Technology Major Project (20431900402), and Innovation Capacity Building Project of Jiangsu province Nanjing Unicorn Academy of innovation (BM2020019). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

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Keywords: SARS-CoV-2; COVID-19; Immunology.

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#SARS-CoV-2–specific #CD8+ T cell responses in #convalescent #COVID19 individuals (J Clin Invest., abstract)

[Source: Journal of Clinical Investigation, full page: (LINK). Abstract, edited.]

SARS-CoV-2–specific CD8+ T cell responses in convalescent COVID-19 individuals

Hassen Kared,1 Andrew D. Redd,2,3 Evan M. Bloch,4 Tania S. Bonny,4 Hermi Sumatoh,1 Faris Kairi,1 Daniel Carbajo,1 Brian Abel,1 Evan W. Newell,1,5 Maria P. Bettinotti,4 Sarah E. Benner,4 Eshan U. Patel,4,6 Kirsten Littlefield,7 Oliver Laeyendecker,2,3 Shmuel Shoham,3 David Sullivan,7 Arturo Casadevall,7 Andrew Pekosz,7 Alessandra Nardin,1 Michael Fehlings,1 Aaron A.R. Tobian,4 and Thomas C. Quinn2,3

Published January 11, 2021

Abstract

Characterization of the T cell response in individuals who recover from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is critical to understanding its contribution to protective immunity. A multiplexed peptide-MHC tetramer approach was used to screen 408 SARS-CoV-2 candidate epitopes for CD8+ T cell recognition in a cross-sectional sample of 30 coronavirus disease 2019 convalescent individuals. T cells were evaluated using a 28-marker phenotypic panel, and findings were modelled against time from diagnosis and from humoral and inflammatory responses. There were 132 SARS-CoV-2–specific CD8+ T cell responses detected across 6 different HLAs, corresponding to 52 unique epitope reactivities. CD8+ T cell responses were detected in almost all convalescent individuals and were directed against several structural and nonstructural target epitopes from the entire SARS-CoV-2 proteome. A unique phenotype for SARS-CoV-2–specific T cells was observed that was distinct from other common virus-specific T cells detected in the same cross-sectional sample and characterized by early differentiation kinetics. Modelling demonstrated a coordinated and dynamic immune response characterized by a decrease in inflammation, increase in neutralizing antibody titer, and differentiation of a specific CD8+ T cell response. Overall, T cells exhibited distinct differentiation into stem cell and transitional memory states (subsets), which may be key to developing durable protection.

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Keywords: SARS-CoV-2; COVID-19; Immunology.

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Breadth and #function of #antibody #response to acute #SARS-CoV-2 infection in #humans (PLOS Pathog., abstract)

[Source: PLOS Pathogens, full page: (LINK). Abstract, edited.]

OPEN ACCESS |  PEER-REVIEWED | RESEARCH ARTICLE

Breadth and function of antibody response to acute SARS-CoV-2 infection in humans

Kuan-Ying A. Huang , Tiong Kit Tan , Ting-Hua Chen, Chung-Guei Huang, Ruth Harvey, Saira Hussain, Cheng-Pin Chen, Adam Harding, Javier Gilbert-Jaramillo, Xu  Liu, Michael Knight, Lisa Schimanski, Shin-Ru Shih,  [ … ], Alain R. Townsend

Published: February 26, 2021 | DOI: https://doi.org/10.1371/journal.ppat.1009352 | This is an uncorrected proof.

Abstract

Serological and plasmablast responses and plasmablast-derived IgG monoclonal antibodies (MAbs) have been analysed in three COVID-19 patients with different clinical severities. Potent humoral responses were detected within 3 weeks of onset of illness in all patients and the serological titre was elicited soon after or concomitantly with peripheral plasmablast response. An average of 13.7% and 13.0% of plasmablast-derived MAbs were reactive with virus spike glycoprotein or nucleocapsid, respectively. A subset of anti-spike (10 of 32) and over half of anti-nucleocapsid (19 of 35) antibodies cross-reacted with other betacoronaviruses tested and harboured extensive somatic mutations, indicative of an expansion of memory B cells upon SARS-CoV-2 infection. Fourteen of 32 anti-spike MAbs, including five anti-receptor-binding domain (RBD), three anti-non-RBD S1 and six anti-S2, neutralised wild-type SARS-CoV-2 in independent assays. Anti-RBD MAbs were further grouped into four cross-inhibiting clusters, of which six antibodies from three separate clusters blocked the binding of RBD to ACE2 and five were neutralising. All ACE2-blocking anti-RBD antibodies were isolated from two recovered patients with prolonged fever, which is compatible with substantial ACE2-blocking response in their sera. At last, the identification of non-competing pairs of neutralising antibodies would offer potential templates for the development of prophylactic and therapeutic agents against SARS-CoV-2.

Author summary

The global COVID-19 outbreak poses a serious threat to human health and antibody-mediated immunity plays a key role in controlling acute viral infection in humans. We report the complete mapping of antibody responses, from serology through to single plasmablast-derived antibody clone, in three COVID-19 patients with different severities. The data show that a subset of anti-spike antibodies and more than half of anti-nucleocapsid plasmablast-derived antibodies cross-react with other betacoronaviruses including human coronavirus OC43, which suggests an expansion of memory B cells upon SARS-CoV-2 infection. Anti-SARS-CoV-2 spike antibody clones target a diverse spectrum of epitopes on the receptor-binding domain (RBD), non-RBD S1 and S2 regions of the spike glycoprotein, 40% of them neutralise wild-type SARS-CoV-2. Anti-RBD antibodies constitute one major part of neutralising antibodies, potent antibodies target three non-overlapping epitopes on the RBD, and the neutralising activity is linked to ACE2-binding blockade. Combination of multiple antibody clones targeting non-overlapping epitopes offer a potential avenue to combat the global outbreak.

Citation: Huang K-YA, Tan TK, Chen T-H, Huang C-G, Harvey R, Hussain S, et al. (2021) Breadth and function of antibody response to acute SARS-CoV-2 infection in humans. PLoS Pathog 17(2): e1009352. https://doi.org/10.1371/journal.ppat.1009352

Editor: Benhur Lee, Icahn School of Medicine at Mount Sinai, UNITED STATES

Received: November 22, 2020; Accepted: February 2, 2021; Published: February 26, 2021

Copyright: © 2021 Huang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The sequences of antibodies are available from the NCBI, with GenBank Accession numbers: MT943491-MT943518. All other relevant data are within the manuscript and its Supporting Information files.

Funding: This work was mainly supported by the grant from Chang Gung Memorial Hospital (BMRPE22) to KYAH. This work was partially supported by the Fast Grant (BRD00230-CF01) to ART, the Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Science (CIFMS), China (2018-I2M-2-002) to TKT, PR, LS and ART, the EPA Cephalosporin Fund and The Townsend–Jeantet Charitable Trust (charity no. 1011770) to TKT, Cancer Research UK (FC001030), the Medical Research Council (FC001030) and the Wellcome Trust (FC001030) to JWM, and the University of Oxford’s COVID-19 Research Response Fund to ART. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: KYAH files a patent application on anti-spike and anti-nucleocapsid antibodies described herein.

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Keywords: SARS-CoV-2; COVID-19; Immunology.

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Homologies between #SARS-CoV-2 and #allergen #proteins may direct T cell-mediated heterologous #immune #responses (Sci Rep., abstract)

[Source: Scientific Reports, full page: (LINK). Abstract, edited.]

Homologies between SARS-CoV-2 and allergen proteins may direct T cell-mediated heterologous immune responses

Kathrin Balz, Abhinav Kaushik, Meng Chen, Franz Cemic, Vanessa Heger, Harald Renz, Kari Nadeau & Chrysanthi Skevaki

Scientific Reports volume 11, Article number: 4792 (2021)

Abstract

The outbreak of the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a public health emergency. Asthma does not represent a risk factor for COVID-19 in several published cohorts. We hypothesized that the SARS-CoV-2 proteome contains T cell epitopes, which are potentially cross-reactive to allergen epitopes. We aimed at identifying homologous peptide sequences by means of two distinct complementary bioinformatics approaches. Pipeline 1 included prediction of MHC Class I and Class II epitopes contained in the SARS-CoV-2 proteome and allergens along with alignment and elaborate ranking approaches. Pipeline 2 involved alignment of SARS-CoV-2 overlapping peptides with known allergen-derived T cell epitopes. Our results indicate a large number of MHC Class I epitope pairs including known as well as de novo predicted allergen T cell epitopes with high probability for cross-reactivity. Allergen sources, such as Aspergillus fumigatus, Phleum pratense and Dermatophagoides species are of particular interest due to their association with multiple cross-reactive candidate peptides, independently of the applied bioinformatic approach. In contrast, peptides derived from food allergens, as well as MHC class II epitopes did not achieve high in silico ranking and were therefore not further investigated. Our findings warrant further experimental confirmation along with examination of the functional importance of such cross-reactive responses.

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Keywords: SARS-CoV-2; COVID-19; Immunology.

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Afucosylated #IgG characterizes enveloped viral #responses and correlates with #COVID19 #severity (Science, abstract)

[Source: Science, full page: (LINK). Abstract, edited.]

Afucosylated IgG characterizes enveloped viral responses and correlates with COVID-19 severity

Mads Delbo Larsen1,2,*, Erik L. de Graaf1,2,*, Myrthe E. Sonneveld1,2,*, H. Rosina Plomp3, Jan Nouta3, Willianne Hoepel4,5, Hung-Jen Chen6,7, Federica Linty1,2, Remco Visser1,2, Maximilian Brinkhaus1,2, Tonći Šuštić1,2, Steven W. de Taeye1,2, Arthur E. H. Bentlage1,2, Suvi Toivonen8, Carolien A. M. Koeleman3, Susanna Sainio8, Neeltje A. Kootstra9, Philip J. M. Brouwer9, Chiara Elisabeth Geyer4,5, Ninotska I. L. Derksen10,11, Gertjan Wolbink12, Menno de Winther6,7, Rogier W. Sanders9,13, Marit J. van Gils9, Sanne de Bruin14, Alexander P. J. Vlaar14, Amsterdam UMC COVID-19, biobank study group†, Theo Rispens10,11, Jeroen den Dunnen4,5, Hans L. Zaaijer15, Manfred Wuhrer3, C. Ellen van der Schoot1,2, Gestur Vidarsson1,2,‡

1 Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands. 2 Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands. 3 Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, Netherlands. 4 Department of Rheumatology and Clinical Immunology, Amsterdam UMC, Amsterdam Rheumatology and Immunology Center, Amsterdam, Netherlands. 5 Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands. 6 Department of Medical Biochemistry, Experimental Vascular Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands. 7 Department of Cardiovascular Sciences, Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands.  8 Finnish Red Cross Blood Service, Helsinki, Finland. 9 Department of Medical Microbiology, Amsterdam UMC, Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands. 10 Department of Immunopathology, Sanquin Research, Amsterdam, Netherlands. 11 Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands. 12 Amsterdam Rheumatology and Immunology Center, Reade, Amsterdam, Netherlands. 13 Weill Medical College, Cornell University, New York, USA. 14 Department of Intensive Care Medicine, Amsterdam UMC (Location AMC), University of Amsterdam, Amsterdam, Netherlands. 15 Department of Blood-borne Infections, Sanquin, Amsterdam, Netherlands.

‡Corresponding author. Email: g.vidarsson@sanquin.nl

* These authors contributed equally to this work.

Science  26 Feb 2021: Vol. 371, Issue 6532, eabc8378 | DOI: 10.1126/science.abc8378

A single sugar makes all the difference

Antibodies are divided into several classes based on their nonvariable tail (Fc) domains. These regions interact with disparate immune cell receptors and complement proteins to help instruct distinct immune responses. The Fc domain of immunoglobulin G (IgG) antibodies contains a conserved N-linked glycan at position 297. However, the particular glycan used at this position is highly variable. IgG lacking core fucosylation at this position initiates enhanced antibody-dependent cellular cytotoxicity by increased affinity to the Fc receptor FcRIIIa. Larsen et al. report that COVID-19 patients with severe symptoms have increased levels of anti–severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG afucosylation compared with patients with mild disease. These findings suggest that treatment of COVID-19 patients with fucosylated anti–SARS-CoV-2 antibodies may circumvent pathologies associated with severe COVID-19.

Science, this issue p. eabc8378

Structured Abstract

INTRODUCTION

Antibody function is often considered static and mostly determined by isotype and subclass. The conserved N-linked glycan at position 297 in the Fc domain of immunoglobulin G (IgG) is essential for an antibody’s effector functions. Moreover, this glycan is highly variable and functionally relevant, especially for the core fucose moiety. IgG lacking core fucosylation (afucosylated IgG) causes increased antibody-dependent cellular cytotoxicity (ADCC) through highly increased IgG-Fc receptor IIIa (FcγRIIIa) affinity. Despite constant levels of total plasma IgG-Fc fucosylation above 90%, specific IgG responses with low core fucosylation have been sporadically reported. These are directed against alloantigens on blood cells and glycoproteins of HIV and dengue virus. In this study, we investigated the induction of afucosylated IgG to various antigens and delineated its dynamics and proinflammatory potential in COVID-19.

RATIONALE

Afucosylated IgG responses have only been found in various alloimmune responses against cellular blood groups and two enveloped viruses. Therefore, we tested the hypothesis that foreign surface–exposed, membrane-embedded proteins induce a specific B cell response that results in afucosylated IgG. We compared immune responses to natural infections by enveloped viruses and nonenveloped viruses, protein subunit vaccination, and live attenuated virus vaccinations. We also assessed the relation to the clinical outcome of such a response in COVID-19.

RESULTS

Analogous to blood cell alloantigens, the response to all enveloped viruses showed clear signatures of afucosylation of the antigen-specific IgG. By contrast, IgG against the nonenveloped virus, parvovirus B19, were highly fucosylated. The extent of afucosylated IgG responses varied, both between individuals and between antigens. The viral context was essential to induce afucosylated IgG because induction did not occur after subunit vaccination against hepatitis B virus. However, afucosylated IgG responses were found in response to attenuated viruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific afucosylated IgG were also found in critically ill COVID-19 patients but not in individuals with mild symptoms. Over the 2 weeks after seroconversion, the amount of fucosylated anti–SARS-CoV-2 IgG increased markedly, in most reaching relative levels similar to those found in total IgG. Afucosylated IgG promoted interleukin-6 (IL-6) release in macrophages cultured in vitro, which is in line with an observed association of SARS-CoV-2–specific IgG afucosylation with IL-6 and C-reactive protein (CRP) in these patients.

CONCLUSION

This work suggests that providing foreign B cell antigens in the context of host cells may be required to trigger an afucosylated IgG immune response. The strength of this response is highly variable for different antigens and between individuals. An afucosylated IgG response is a potent immune response, honed for the destruction of target cells by FcγRIII-expressing natural killer (NK) and myeloid cells. This may sometimes be desirable—for example, against HIV—and can be achieved in vaccines by providing the target as a surface protein, as is the case with attenuated viral vaccines or mRNA vaccines. However, for SARS-CoV-2, this afucosylated IgG response may promote the exacerbation of COVID-19 under conditions with high viral loads at the time of seroconversion.

Abstract

Immunoglobulin G (IgG) antibodies are crucial for protection against invading pathogens. A highly conserved N-linked glycan within the IgG-Fc tail, which is essential for IgG function, shows variable composition in humans. Afucosylated IgG variants are already used in anticancer therapeutic antibodies for their increased activity through Fc receptors (FcγRIIIa). Here, we report that afucosylated IgG (approximately 6% of total IgG in humans) are specifically formed against enveloped viruses but generally not against other antigens. This mediates stronger FcγRIIIa responses but also amplifies brewing cytokine storms and immune-mediated pathologies. Critically ill COVID-19 patients, but not those with mild symptoms, had high concentrations of afucosylated IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), amplifying proinflammatory cytokine release and acute phase responses. Thus, antibody glycosylation plays a critical role in immune responses to enveloped viruses, including COVID-19.

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Keywords: SARS-CoV-2; COVID-19; Immunopathology; Immunology.

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#Association of #SARS-CoV-2 #Seropositive #Antibody #Test With #Risk of Future Infection (JAMA Intern Med., abstract)

[Source: JAMA Internal Medicine, full page: (LINK). Abstract, edited.]

Association of SARS-CoV-2 Seropositive Antibody Test With Risk of Future Infection

Raymond A. Harvey, MPH1; Jeremy A. Rassen, ScD1; Carly A. Kabelac, BS1; Wendy Turenne, MS1; Sandy Leonard, MPH2; Reyna Klesh, MS2; William A. Meyer III, PhD, D(ABMM), MLS(ASCP)CM3; Harvey W. Kaufman, MD, MBA; Steve Anderson, PhD4; Oren Cohen, MD4; Valentina I. Petkov, MD, MPH5; Kathy A. Cronin, PhD5; Alison L. Van Dyke, MD, PhD5; Douglas R. Lowy, MD5; Norman E. Sharpless, MD5; Lynne T. Penberthy, MD, MPH5

Author Affiliations: 1 Aetion, Inc, New York, New York; 2 HealthVerity, Philadelphia, Pennsylvania; 3 Quest Diagnostics, Secaucus, New Jersey; 4 LabCorp, Burlington, North Carolina; 5 National Cancer Institute, National Institutes of Health, Bethesda, Maryland

JAMA Intern Med. Published online February 24, 2021. doi:10.1001/jamainternmed.2021.0366

Key Points

• Question  – Can observational clinical data from commercial laboratories be used to evaluate the comparative risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for individuals who are antibody positive vs those who are antibody negative?
• Finding  – In this cohort study of more than 3.2 million US patients with a SARS-CoV-2 antibody test, 0.3% of those indexed with positive test results had evidence of a positive nucleic acid amplification test beyond 90 days after index, compared with 3.0% indexed with negative antibody test results.
• Meaning  – Individuals who are seropositive for SARS-CoV-2 based on commercial assays may be at decreased future risk of SARS-CoV-2 infection.

Abstract

Importance  

Understanding the effect of serum antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on susceptibility to infection is important for identifying at-risk populations and could have implications for vaccine deployment.

Objective  

The study purpose was to evaluate evidence of SARS-CoV-2 infection based on diagnostic nucleic acid amplification test (NAAT) among patients with positive vs negative test results for antibodies in an observational descriptive cohort study of clinical laboratory and linked claims data.

Design, Setting, and Participants  

The study created cohorts from a deidentified data set composed of commercial laboratory tests, medical and pharmacy claims, electronic health records, and hospital chargemaster data. Patients were categorized as antibody-positive or antibody-negative according to their first SARS-CoV-2 antibody test in the database.

Main Outcomes and Measures  

Primary end points were post-index diagnostic NAAT results, with infection defined as a positive diagnostic test post-index, measured in 30-day intervals (0-30, 31-60, 61-90, >90 days). Additional measures included demographic, geographic, and clinical characteristics at the time of the index antibody test, including recorded signs and symptoms or prior evidence of coronavirus 2019 (COVID) diagnoses or positive NAAT results and recorded comorbidities.

Results  

The cohort included 3 257 478 unique patients with an index antibody test; 56% were female with a median (SD) age of 48 (20) years. Of these, 2 876 773 (88.3%) had a negative index antibody result, and 378 606 (11.6%) had a positive index antibody result. Patients with a negative antibody test result were older than those with a positive result (mean age 48 vs 44 years). Of index-positive patients, 18.4% converted to seronegative over the follow-up period. During the follow-up periods, the ratio (95% CI) of positive NAAT results among individuals who had a positive antibody test at index vs those with a negative antibody test at index was 2.85 (95% CI, 2.73-2.97) at 0 to 30 days, 0.67 (95% CI, 0.6-0.74) at 31 to 60 days, 0.29 (95% CI, 0.24-0.35) at 61 to 90 days, and 0.10 (95% CI, 0.05-0.19) at more than 90 days.

Conclusions and Relevance  

In this cohort study, patients with positive antibody test results were initially more likely to have positive NAAT results, consistent with prolonged RNA shedding, but became markedly less likely to have positive NAAT results over time, suggesting that seropositivity is associated with protection from infection. The duration of protection is unknown, and protection may wane over time.

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Keywords: SARS-CoV-2; COVID-19; Serology; Immunology.

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#Persistence of #antibodies to #SARS-CoV-2 in relation to symptoms in a nationwide prospective study (Clin Infect Dis., abstract)

[Source: Clinical Infectious Diseases, full page: (LINK). Abstract, edited.]

Persistence of antibodies to SARS-CoV-2 in relation to symptoms in a nationwide prospective study

Gerco den Hartog, PhD, Eric R A Vos, MSc, Lotus L van den Hoogen, PhD, Michiel van Boven, PhD, Rutger M Schepp, BSc, Gaby Smits, MSc, Jeffrey van Vliet, Linde Woudstra, PhD, Alienke J Wijmenga-Monsuur, PhD, Cheyenne C E van Hagen, MSc, Elisabeth A M Sanders, MD, PhD, Hester E de Melker, PhD, Fiona R M van der Klis, PhD, Robert S van Binnendijk, PhD

Clinical Infectious Diseases, ciab172, https://doi.org/10.1093/cid/ciab172

Published: 24 February 2021

Abstract

Background

Assessing the duration of immunity following infection with SARS-CoV-2 is a first priority to gauge the degree of protection following infection. Such knowledge is lacking especially in the general population. Here, we studied changes in Immunoglobulin (Ig) isotype seropositivity and IgG binding strength of SARS-CoV-2-specific serum antibodies up to 7 months following onset of symptoms in a nationwide sample.

Methods

Participants from a prospective representative serological study in the Netherlands were included based on IgG seroconversion to the Spike S1 protein of SARS-CoV-2 (N=353), with up to three consecutive serum samples per seroconverted participant (N=738). IgM, IgA and IgG antibody concentrations to S1, and increase in IgG avidity in relation to time since onset of disease symptoms, were determined.

Results

While SARS-CoV-2-specific IgM and IgA antibodies declined rapidly after the first month post onset of disease, specific IgG was still present in 92% (95% confidence interval, CI, 89-95) of the participants after 7 months. The estimated 2-fold decrease of IgG antibodies was 158 days (95% CI 136-189). Concentrations sustained better in persons reporting significant symptoms compared to asymptomatic persons or those with mild upper respiratory complaints only. Similarly, avidity of IgG antibodies for symptomatic persons showed a steeper increase over time compared with persons with mild or no symptoms (p=0.022).

Conclusion

SARS-CoV-2-specific IgG antibodies persist and show increasing avidity over time, indicative of underlying immune maturation. These data support development of immune memory against SARS-CoV-2 providing insight into protection of the general unvaccinated part of the population.

Immunoglobulin G, COVID-19, symptoms, avidity/maturation, decay

Issue Section: Major Article

© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America.

This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

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Keywords: SARS-CoV-2; COVID-19; Serology; Immunology.

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Prior #COVID19 #Infection and #Antibody Response to Single Versus Double Dose #mRNA #SARS-CoV-2 #Vaccination (MedRxIV, abstract)

[Source: MedRxIV, full page: (LINK). Abstract, edited.]

Prior COVID-19 Infection and Antibody Response to Single Versus Double Dose mRNA SARS-CoV-2 Vaccination

Joseph E. Ebinger, Justyna Fert-Bober, Ignat Printsev, Min Wu, Nancy Sun, Jane C. Figueiredo, Jennifer Van Eyk, Jonathan Braun, Susan Cheng, Kimia Sobhani

doi: https://doi.org/10.1101/2021.02.23.21252230 | This article is a preprint and has not been certified by peer review. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

Abstract

The double dose regimen for mRNA vaccines against SARS-CoV-2 presents both a hope and a challenge for global efforts to curb the COVID-19 pandemic. With supply chain logistics impacting the rollout of population-scale vaccination programs, increasing attention has turned to the potential efficacy of single versus double dose vaccine administration for select individuals. To this end, we examined response to Pfizer-BioNTech mRNA vaccine in a large cohort of healthcare workers including those with versus without prior COVID-19 infection. For all participants, we quantified circulating levels of SARS-CoV-2 anti-spike (S) protein IgG at baseline prior to vaccine, after vaccine dose 1, and after vaccine dose 2. We observed that the anti-S IgG antibody response following a single vaccine dose in persons who had recovered from confirmed prior COVID-19 infection was similar to the antibody response following two doses of vaccine in persons without prior infection (P>0.57). Patterns were similar for the post-vaccine symptoms experienced by infection recovered persons following their first dose compared to the symptoms experienced by infection naive persons following their second dose (P=0.66). These results support the premise that a single dose of mRNA vaccine could provoke in COVID-19 recovered individuals a level of immunity that is comparable to that seen in infection naive persons following a double dose regimen. Additional studies are needed to validate our findings, which could allow for public health programs to expand the reach of population wide vaccination efforts.

Competing Interest Statement: The authors have declared no competing interest.

Funding Statement: This work was supported in part by Cedars-Sinai Medical Center, the Erika J Glazer Family Foundation, the F. Widjaja Family Foundation, the Helmsley Charitable Trust, and NIH grants U54-CA260591 and K23-HL153888.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

All participants provided written informed consent and all study protocols were approved by the Cedars-Sinai institutional review board.

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv

Copyright – The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.

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Keywords: SARS-CoV-2; COVID-19; Vaccines; Immunology.

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Quantitative #Measurement of #IgG to #SARS-CoV-2 #Proteins Using ImmunoCAP (Int Arch Allergy Immunol., abstract)

[Source: International Archives of Allergy and Immunology, full page: (LINK). Abstract, edited.]

Quantitative Measurement of IgG to Severe Acute Respiratory Syndrome Coronavirus-2 Proteins Using ImmunoCAP

Keshavarz B.a · Wiencek J.R.b · Workman L.J.a · Straesser M.D.a · Muehling L.M.a · Canderan G.a · Drago F.c · Bonham C.A.d · Sturek J.M.d · Ramani C.d · McNamara C.A.c · Woodfolk J.A.a · Kadl A.d,e · Platts-Mills T.A.E.a · Wilson J.M.a

Author affiliations: a Division of Allergy & Clinical Immunology, Department of Medicine, University of Virginia, Charlottesville, VA, USA; b Department of Pathology, University of Virginia, Charlottesville, VA, USA; c Division of Cardiovascular Medicine and the Robert M. Berne Cardiovascular Center, University of Virginia, Charlottesville, VA, USA; d Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA, USA; e Department of Pharmacology, University of Virginia, Charlottesville, VA, USA

Int Arch Allergy Immunol | DOI: https://doi.org/10.1159/000514203

Abstract

Background:

Detailed understanding of the immune response to severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the cause of coronavirus disease 2019 (CO­VID-19) has been hampered by a lack of quantitative antibody assays.

Objective:

The objective was to develop a quantitative assay for IgG to SARS-CoV-2 proteins that could be implemented in clinical and research laboratories.

Methods:

The biotin-streptavidin technique was used to conjugate SARS-CoV-2 spike receptor-binding domain (RBD) or nucleocapsid protein to the solid phase of the ImmunoCAP. Plasma and serum samples from patients hospitalized with COVID-19 (n = 60) and samples from donors banked before the emergence of COVID-19 (n = 109) were used in the assay. SARS-CoV-2 IgG levels were followed longitudinally in a subset of samples and were related to total IgG and IgG to reference antigens using an ImmunoCAP 250 platform.

Results:

At a cutoff of 2.5 μg/mL, the assay demonstrated sensitivity and specificity exceeding 95% for IgG to both SARS-CoV-2 proteins. Among 36 patients evaluated in a post-hospital follow-up clinic, median levels of IgG to spike-RBD and nucleocapsid were 34.7 μg/mL (IQR 18–52) and 24.5 μg/mL (IQR 9–59), respectively. Among 17 patients with longitudinal samples, there was a wide variation in the magnitude of IgG responses, but generally the response to spike-RBD and to nucleocapsid occurred in parallel, with peak levels approaching 100 μg/mL, or 1% of total IgG.

Conclusions:

We have described a quantitative assay to measure IgG to SARS-CoV-2 that could be used in clinical and research laboratories and implemented at scale. The assay can easily be adapted to measure IgG to mutated COVID-19 proteins, has good performance characteristics, and has a readout in standardized units.

© 2021 The Author(s) Published by S. Karger AG, Basel

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Keywords: SARS-CoV-2; COVID-19; Immunology.

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Seven-month #kinetics of #SARS-CoV-2 #antibodies and protective role of pre-existing antibodies to seasonal #human #coronaviruses on #COVID19 (MedRxIV, abstract)

[Source: MedRxIV, full page: (LINK). Abstract, edited.]

Seven-month kinetics of SARS-CoV-2 antibodies and protective role of pre-existing antibodies to seasonal human coronaviruses on COVID-19

Natalia Ortega,   Marta Ribes,   Marta Vidal,   Rocio Rubio,    Ruth Aguilar, Sarah Williams,   Diana Barrios,   Selena Alonso, Pablo Hernandez-Luis,   Robert Andrew Mitchell,   Chenjerai Jairoce,   Angeline Marie Cruz,   Alfons Jimenez,   Rebeca Santano, Susana Mendez,   Montserrat Lamoglia, Neus Rosell,   Anna Llupia,   Laura Puyol, Jordi Chi,   Natalia Rodrigo,   Daniel Parras,   Pau Serra,   Alfredo Mayor, Sonia Barroso, Pilar Varela,   Anna Vilella,   Antoni Trilla,   Pere Santamaria,   Carlo Carolis, Marta Tortajada,   Luis Izquierdo,   Ana Angulo,   Pablo Engel,   Alberto Garcia-Basteiro,   Gemma Moncunill,   Carlota Dobano

doi: https://doi.org/10.1101/2021.02.22.21252150 | This article is a preprint and has not been certified by peer review. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

Abstract

Unraveling long-term kinetics of antibodies to SARS-CoV-2 and the factors influencing its course, like prior antibody levels to human coronaviruses causing common cold (HCoVs), is essential to understand protective immunity and effective surveillance strategies. Antibody levels against six SARS-CoV-2 and four HCoV antigens were quantified by Luminex, and antibody neutralization capacity was assessed by flow cytometry in a cohort of health care workers followed-up for 6 months. Seroprevalence increased over time from 13.5% (month 0) and 15.6% (month 1), to 16.4% (month 6). Levels of antibodies were stable over time, except IgG against nucleocapsid antigen and IgM levels that waned. After the peak response, anti-spike antibody levels increased from ~150 days post-symptom onset in all individuals (73% for IgG), in the absence of any evidence of re-exposure. The neutralizing capacity of antibodies was maintained. Pre-existing antibodies to alpha-HCoV were lower in individuals who subsequently seroconverted for SARS-CoV-2. IgG and IgA to HCoV were significantly higher in asymptomatic than symptomatic seropositive individuals. Thus, pre-existing cross-reactive HCoVs antibodies could have a protective effect against SARS-CoV-2 infection and COVID-19 disease.

Competing Interest Statement: The authors have declared no competing interest.

Funding Statement: This work was supported by Institut de Salut Global de Barcelona (ISGlobal) internal funds; in-kind contributions of Hospital Clinic de Barcelona, and European Institute of Innovation and Technology (EIT) Health (grant number 20877), supported by the European Institute of Innovation and Technology, a body of the European Union receiving support from the H2020 Research and Innovation Programme; by the Fundacio Privada Daniel Bravo Andreu; Ministerio de Ciencia e Innovacion through the Centro de Excelencia Severo Ochoa 2019-2023 program (grant number CEX2018-000806-S); and the Catalan Government through the Centres de Recerca de Catalunya program (for P.S.: 2017-SGR-3380 and MINECO RTI2018-093964-B-I00). Development of SARS-CoV-2 reagents was partially supported by the National Institute of Allergy and Infectious Diseases Centers of Excellence for Influenza Research and Surveillance (contract number HHSN272201400008C). G. M. was supported by the Departament de Salut, Generalitat de Catalunya (grant number SLT006/17/00109). L. I. work was supported by PID2019-110810RB-I00 grant from the Spanish Ministry of Science & Innovation.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was approved by the Ethics Committee at HCB (Ref number: HCB/2020/0336).

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv

Copyright  – The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.

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Keywords: SARS-CoV-2; COVID-19; Serology; Seroprevalence; Immunology.

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