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2.
Cell Rep ; 39(13): 111013, 2022 Jun 28.
Article in English | MEDLINE | ID: covidwho-1885674

ABSTRACT

Spacing of BNT162b2 mRNA doses beyond 3 weeks raises concerns about vaccine efficacy. We longitudinally analyze B cell, T cell, and humoral responses to two BNT162b2 mRNA doses administered 16 weeks apart in 53 SARS-CoV-2 naive and previously infected donors. This regimen elicits robust RBD-specific B cell responses whose kinetics differs between cohorts, the second dose leading to increased magnitude in naive participants only. While boosting does not increase magnitude of CD4+ T cell responses further compared with the first dose, unsupervised clustering of single-cell features reveals phenotypic and functional shifts over time and between cohorts. Integrated analysis shows longitudinal immune component-specific associations, with early T helper responses post first dose correlating with B cell responses after the second dose, and memory T helper generated between doses correlating with CD8 T cell responses after boosting. Therefore, boosting elicits a robust cellular recall response after the 16-week interval, indicating functional immune memory.


Subject(s)
COVID-19 , Viral Vaccines , Antibodies, Viral , BNT162 Vaccine , Humans , Immunity, Humoral , RNA, Messenger , SARS-CoV-2
3.
Cell Rep ; 38(7): 110368, 2022 02 15.
Article in English | MEDLINE | ID: covidwho-1649284

ABSTRACT

Emerging evidence indicates that both neutralizing and Fc-mediated effector functions of antibodies contribute to protection against SARS-CoV-2. It is unclear whether Fc-effector functions alone can protect against SARS-CoV-2. Here, we isolated CV3-13, a non-neutralizing antibody, from a convalescent individual with potent Fc-mediated effector functions. The cryoelectron microscopy structure of CV3-13 in complex with the SARS-CoV-2 spike reveals that the antibody binds from a distinct angle of approach to an N-terminal domain (NTD) epitope that only partially overlaps with the NTD supersite recognized by neutralizing antibodies. CV3-13 does not alter the replication dynamics of SARS-CoV-2 in K18-hACE2 mice, but its Fc-enhanced version significantly delays virus spread, neuroinvasion, and death in prophylactic settings. Interestingly, the combination of Fc-enhanced non-neutralizing CV3-13 with Fc-compromised neutralizing CV3-25 completely protects mice from lethal SARS-CoV-2 infection. Altogether, our data demonstrate that efficient Fc-mediated effector functions can potently contribute to the in vivo efficacy of anti-SARS-CoV-2 antibodies.


Subject(s)
Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , COVID-19/therapy , Animals , Antibodies, Viral/chemistry , Antibody-Dependent Cell Cytotoxicity , COVID-19/mortality , COVID-19/prevention & control , COVID-19/transmission , Disease Models, Animal , Epitopes , Humans , Immunization, Passive/mortality , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/metabolism , Immunoglobulin Fc Fragments/genetics , Immunoglobulin Fc Fragments/immunology , Mice , Protein Binding , Protein Conformation , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
4.
Viruses ; 14(1)2021 12 21.
Article in English | MEDLINE | ID: covidwho-1580417

ABSTRACT

Different serological assays were rapidly generated to study humoral responses against the SARS-CoV-2 Spike glycoprotein. Due to the intrinsic difficulty of working with SARS-CoV-2 authentic virus, most serological assays use recombinant forms of the Spike glycoprotein or its receptor binding domain (RBD). Cell-based assays expressing different forms of the Spike, as well as pseudoviral assays, are also widely used. To evaluate whether these assays recapitulate findings generated when the Spike is expressed in its physiological context (at the surface of the infected primary cells), we developed an intracellular staining against the SARS-CoV-2 nucleocapsid (N) to distinguish infected from uninfected cells. Human airway epithelial cells (pAECs) were infected with authentic SARS-CoV-2 D614G or Alpha variants. We observed robust cell-surface expression of the SARS-CoV-2 Spike at the surface of the infected pAECs using the conformational-independent anti-S2 CV3-25 antibody. The infected cells were also readily recognized by plasma from convalescent and vaccinated individuals and correlated with several serological assays. This suggests that the antigenicity of the Spike present at the surface of the infected primary cells is maintained in serological assays involving expression of the native full-length Spike.


Subject(s)
Cell Membrane/metabolism , Epithelial Cells/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Antibodies, Viral/immunology , Antibody-Dependent Cell Cytotoxicity , Bronchioles/cytology , Cells, Cultured , Coronavirus Nucleocapsid Proteins/metabolism , Epithelial Cells/virology , HEK293 Cells , Humans , Neutralization Tests , Phosphoproteins/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
5.
Cell Rep ; 38(2): 110210, 2022 01 11.
Article in English | MEDLINE | ID: covidwho-1568559

ABSTRACT

Emerging variants of concern for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transmit more efficiently and partially evade protective immune responses, thus necessitating continued refinement of antibody therapies and immunogen design. Here, we elucidate the structural basis and mode of action for two potent SARS-CoV-2 spike (S)-neutralizing monoclonal antibodies, CV3-1 and CV3-25, which remain effective against emerging variants of concern in vitro and in vivo. CV3-1 binds to the (485-GFN-487) loop within the receptor-binding domain (RBD) in the "RBD-up" position and triggers potent shedding of the S1 subunit. In contrast, CV3-25 inhibits membrane fusion by binding to an epitope in the stem helix region of the S2 subunit that is highly conserved among ß-coronaviruses. Thus, vaccine immunogen designs that incorporate the conserved regions in the RBD and stem helix region are candidates to elicit pan-coronavirus protective immune responses.

6.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-296129

ABSTRACT

SUMMARY While the standard regimen of the BNT162b2 mRNA vaccine includes two doses administered three weeks apart, some public health authorities decided to space them, raising concerns about vaccine efficacy. Here, we analyzed longitudinal humoral responses including antibody binding, Fc-mediated effector functions and neutralizing activity against the D614G strain but also variants of concern and SARS-CoV-1 in a cohort of SARS-CoV-2 naïve and previously infected individuals, with an interval of sixteen weeks between the two doses. While the administration of a second dose to previously infected individuals did not significantly improve humoral responses, we observed a significant increase of humoral responses in naïve individuals after the 16-weeks delayed second shot, achieving similar levels as in previously infected individuals. We compared these responses to those elicited in individuals receiving a short (4-weeks) dose interval. For the naïve donors, these responses were superior to those elicited by the short dose interval.

7.
Cell Host Microbe ; 30(1): 97-109.e5, 2022 01 12.
Article in English | MEDLINE | ID: covidwho-1549683

ABSTRACT

The standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered three weeks apart. However, some public health authorities spaced these doses, raising questions about efficacy. We analyzed longitudinal humoral responses against the D614G strain and variants of concern for SARS-CoV-2 in a cohort of SARS-CoV-2-naive and previously infected individuals who received the BNT162b2 mRNA vaccine with sixteen weeks between doses. While administering a second dose to previously infected individuals did not significantly improve humoral responses, these responses significantly increased in naive individuals after a 16-week spaced second dose, achieving similar levels as in previously infected individuals. Comparing these responses to those elicited in individuals receiving a short (4-week) dose interval showed that a 16-week interval induced more robust responses among naive vaccinees. These findings suggest that a longer interval between vaccine doses does not compromise efficacy and may allow greater flexibility in vaccine administration.


Subject(s)
/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Immunity, Humoral/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Synthetic/immunology , /immunology , Adult , Aged , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/virology , Female , Humans , Male , Middle Aged , Vaccination/methods , Young Adult
8.
Sci Adv ; 7(48): eabj5629, 2021 Nov 26.
Article in English | MEDLINE | ID: covidwho-1537882

ABSTRACT

Despite advances in COVID-19 management, identifying patients evolving toward death remains challenging. To identify early predictors of mortality within 60 days of symptom onset (DSO), we performed immunovirological assessments on plasma from 279 individuals. On samples collected at DSO11 in a discovery cohort, high severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA (vRNA), low receptor binding domain­specific immunoglobulin G and antibody-dependent cellular cytotoxicity, and elevated cytokines and tissue injury markers were strongly associated with mortality, including in patients on mechanical ventilation. A three-variable model of vRNA, with predefined adjustment by age and sex, robustly identified patients with fatal outcome (adjusted hazard ratio for log-transformed vRNA = 3.5). This model remained robust in independent validation and confirmation cohorts. Since plasma vRNA's predictive accuracy was maintained at earlier time points, its quantitation can help us understand disease heterogeneity and identify patients who may benefit from new therapies.

9.
Microbiol Spectr ; 9(3): e0088621, 2021 12 22.
Article in English | MEDLINE | ID: covidwho-1522922

ABSTRACT

The evaluation of humoral protective immunity against SARS-CoV-2 remains crucial in understanding both natural immunity and protective immunity conferred by the several vaccines implemented in the fight against COVID-19. The reference standard for the quantification of antibodies capable of neutralizing SARS-CoV-2 is the plaque-reduction neutralization test (PRNT). However, given that it is a laboratory-developed assay, validation is crucial in order to ensure sufficient specificity and intra- and interassay precision. In addition, a multitude of other serological assays have been developed, including enzyme-linked immunosorbent assay (ELISA), flow cytometry-based assays, luciferase-based lentiviral pseudotype assays, and commercially available human ACE2 receptor-blocking antibody tests, which offer practical advantages in the evaluation of the protective humoral response against SARS-CoV-2. In this study, we validated a SARS-CoV-2 PRNT to assess both 50% and 90% neutralization of SARS-CoV-2 according to guidelines outlined by the World Health Organization. Upon validation, the reference-standard PRNT demonstrated excellent specificity and both intra- and interassay precision. Using the validated assay as a reference standard, we characterized the neutralizing antibody response in specimens from patients with laboratory-confirmed COVID-19. Finally, we conducted a small-scale multilaboratory comparison of alternate SARS-CoV-2 PRNTs and surrogate neutralization tests. These assays demonstrated substantial to perfect interrater agreement with the reference-standard PRNT and offer useful alternatives to assess humoral immunity against SARS-CoV-2. IMPORTANCE SARS-CoV-2, the causal agent of COVID-19, has infected over 246 million people and led to over 5 million deaths as of October 2021. With the approval of several efficacious COVID-19 vaccines, methods to evaluate protective immune responses will be crucial for the understanding of long-term immunity in the rapidly growing vaccinated population. The PRNT, which quantifies SARS-CoV-2-neutralizing antibodies, is used widely as a reference standard to validate new platforms but has not undergone substantial validation to ensure excellent inter- and intraassay precision and specificity. Our work is significant, as it describes the thorough validation of a PRNT, which we then used as a reference standard for the comparison of several alternative serological methods to measure SARS-CoV-2-neutralizing antibodies. These assays demonstrated excellent agreement with the reference-standard PRNT and include high-throughput platforms, which can greatly enhance capacity to assess both natural and vaccine-induced protective immunity against SARS-CoV-2.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Immunity, Humoral/immunology , Neutralization Tests/methods , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Neutralizing , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Diagnostic Tests, Routine , Enzyme-Linked Immunosorbent Assay/methods , HEK293 Cells , Humans , Immunity , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Vero Cells
10.
Virology ; 563: 134-145, 2021 11.
Article in English | MEDLINE | ID: covidwho-1401925

ABSTRACT

Towards the end of 2020, multiple variants of concern (VOCs) and variants of interest (VOIs) have arisen from the original SARS-CoV-2 Wuhan-Hu-1 strain. Mutations in the Spike protein are highly scrutinized for their impact on transmissibility, pathogenesis and vaccine efficacy. Here, we contribute to the growing body of literature on emerging variants by evaluating the impact of single mutations on the overall antigenicity of selected variants and their binding to the ACE2 receptor. We observe a differential contribution of single mutants to the global variants phenotype related to ACE2 interaction and antigenicity. Using biolayer interferometry, we observe that enhanced ACE2 interaction is mostly modulated by a decrease in off-rate. Finally, we made the interesting observation that the Spikes from tested emerging variants bind better to ACE2 at 37°C compared to the D614G variant. Whether improved ACE2 binding at higher temperature facilitates emerging variants transmission remain to be demonstrated.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Binding Sites , HEK293 Cells , Humans , Mutation , Protein Binding , Protein Interaction Domains and Motifs
11.
Viruses ; 12(11)2020 10 26.
Article in English | MEDLINE | ID: covidwho-1389519

ABSTRACT

Convalescent plasma from SARS-CoV-2 infected individuals and monoclonal antibodies were shown to potently neutralize viral and pseudoviral particles carrying the S glycoprotein. However, a non-negligent proportion of plasma samples from infected individuals, as well as S-specific monoclonal antibodies, were reported to be non-neutralizing despite efficient interaction with the S glycoprotein in different biochemical assays using soluble recombinant forms of S or when expressed at the cell surface. How neutralization relates to the binding of S glycoprotein in the context of viral particles remains to be established. Here, we developed a pseudovirus capture assay (VCA) to measure the capacity of plasma samples or antibodies immobilized on ELISA plates to bind to membrane-bound S glycoproteins from SARS-CoV-2 expressed at the surface of lentiviral particles. By performing VCA, ELISA, and neutralization assays, we observed a strong correlation between these parameters. However, while we found that plasma samples unable to capture viral particles did not neutralize, capture did not guarantee neutralization, indicating that the capacity of antibodies to bind to the S glycoprotein at the surface of pseudoviral particles is required but not sufficient to mediate neutralization. Altogether, our results highlight the importance of better understanding the inactivation of S by plasma and neutralizing antibodies.


Subject(s)
Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Immobilized/immunology , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19 , Cell Line , Convalescence , HEK293 Cells , Humans , Neutralization Tests , Pandemics , SARS-CoV-2 , Time Factors
12.
J Biol Chem ; 297(4): 101151, 2021 10.
Article in English | MEDLINE | ID: covidwho-1377741

ABSTRACT

The seasonal nature of outbreaks of respiratory viral infections with increased transmission during low temperatures has been well established. Accordingly, temperature has been suggested to play a role on the viability and transmissibility of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The receptor-binding domain (RBD) of the Spike glycoprotein is known to bind to its host receptor angiotensin-converting enzyme 2 (ACE2) to initiate viral fusion. Using biochemical, biophysical, and functional assays to dissect the effect of temperature on the receptor-Spike interaction, we observed a significant and stepwise increase in RBD-ACE2 affinity at low temperatures, resulting in slower dissociation kinetics. This translated into enhanced interaction of the full Spike glycoprotein with the ACE2 receptor and higher viral attachment at low temperatures. Interestingly, the RBD N501Y mutation, present in emerging variants of concern (VOCs) that are fueling the pandemic worldwide (including the B.1.1.7 (α) lineage), bypassed this requirement. This data suggests that the acquisition of N501Y reflects an adaptation to warmer climates, a hypothesis that remains to be tested.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/chemistry , COVID-19/pathology , COVID-19/virology , Calorimetry , Humans , Interferometry , Polymorphism, Single Nucleotide , Protein Binding , Protein Structure, Quaternary , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Temperature , Thermodynamics
13.
Immunity ; 54(9): 2143-2158.e15, 2021 09 14.
Article in English | MEDLINE | ID: covidwho-1364125

ABSTRACT

Neutralizing antibodies (NAbs) are effective in treating COVID-19, but the mechanism of immune protection is not fully understood. Here, we applied live bioluminescence imaging (BLI) to monitor the real-time effects of NAb treatment during prophylaxis and therapy of K18-hACE2 mice intranasally infected with SARS-CoV-2-nanoluciferase. Real-time imaging revealed that the virus spread sequentially from the nasal cavity to the lungs in mice and thereafter systemically to various organs including the brain, culminating in death. Highly potent NAbs from a COVID-19 convalescent subject prevented, and also effectively resolved, established infection when administered within three days. In addition to direct neutralization, depletion studies indicated that Fc effector interactions of NAbs with monocytes, neutrophils, and natural killer cells were required to effectively dampen inflammatory responses and limit immunopathology. Our study highlights that both Fab and Fc effector functions of NAbs are essential for optimal in vivo efficacy against SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , Brain/pathology , COVID-19/immunology , Lung/pathology , SARS-CoV-2/physiology , Testis/pathology , Angiotensin-Converting Enzyme 2/genetics , Animals , Antibodies, Neutralizing/genetics , Antibodies, Viral/genetics , Brain/virology , COVID-19/therapy , Cells, Cultured , Disease Models, Animal , Humans , Immunoglobulin Fc Fragments/genetics , Luciferases/genetics , Luminescent Measurements , Lung/virology , Male , Mice , Mice, Transgenic , Testis/virology
14.
Cell Rep Med ; 2(6): 100290, 2021 06 15.
Article in English | MEDLINE | ID: covidwho-1307252

ABSTRACT

With the recent approval of highly effective coronavirus disease 2019 (COVID-19) vaccines, functional and lasting immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently under investigation as antibody levels in plasma were shown to decline during convalescence. Since the absence of antibodies does not equate to absence of immune memory, we evaluate the presence of SARS-CoV-2-specific memory B cells in convalescent individuals. Here, we report a longitudinal assessment of humoral immune responses on 32 donors up to 8 months post-symptom onset. Our observations indicate that anti-Spike and anti-receptor binding domain (RBD) immunoglobulin M (IgM) in plasma decay rapidly, whereas the reduction of IgG is less prominent. Neutralizing activity also declines rapidly when compared to Fc-effector functions. Concomitantly, the frequencies of RBD-specific IgM+ B cells wane significantly when compared to RBD-specific IgG+ B cells, which remain stable. Our results add to the current understanding of immune memory following SARS-CoV-2 infection, which is critical for secondary infection prevention and vaccine efficacy.

15.
Open Forum Infect Dis ; 8(6): ofab220, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1276208

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) surrogate neutralization assays that obviate the need for viral culture offer substantial advantages regarding throughput and cost. The cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript) is the first such commercially available assay that detects antibodies that block receptor-binding domain (RBD)/angiotensin-converting enzyme (ACE)-2 interaction. We aimed to evaluate cPass to inform its use and assess its added value compared with anti-RBD enzyme-linked immunosorbent assays (ELISAs). METHODS: Serum reference panels comprising 205 specimens were used to compare cPass to plaque-reduction neutralization test (PRNT) and a pseudotyped lentiviral neutralization (PLV) assay for detection of neutralizing antibodies. We assessed the correlation of cPass with an ELISA detecting anti-RBD immunoglobulin (Ig)G, IgM, and IgA antibodies at a single timepoint and across intervals from onset of symptoms of SARS-CoV-2 infection. RESULTS: Compared with PRNT-50, cPass sensitivity ranged from 77% to 100% and specificity was 95% to 100%. Sensitivity was also high compared with the pseudotyped lentiviral neutralization assay (93%; 95% confidence interval [CI], 85-97), but specificity was lower (58%; 95% CI, 48-67). Highest agreement between cPass and ELISA was for anti-RBD IgG (r = 0.823). Against the pseudotyped lentiviral neutralization assay, anti-RBD IgG sensitivity (99%; 95% CI, 94-100) was very similar to that of cPass, but overall specificity was lower (37%; 95% CI, 28-47). Against PRNT-50, results of cPass and anti-RBD IgG were nearly identical. CONCLUSIONS: The added value of cPass compared with an IgG anti-RBD ELISA was modest.

16.
Cell Host Microbe ; 29(7): 1137-1150.e6, 2021 07 14.
Article in English | MEDLINE | ID: covidwho-1252574

ABSTRACT

While the standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered 3 weeks apart, some public health authorities are spacing these doses, raising concerns about efficacy. However, data indicate that a single dose can be up to 90% effective starting 14 days post-administration. To assess the mechanisms contributing to protection, we analyzed humoral and T cell responses three weeks after a single BNT162b2 dose. We observed weak neutralizing activity elicited in SARS-CoV-2 naive individuals but strong anti-receptor binding domain and spike antibodies with Fc-mediated effector functions and cellular CD4+ T cell responses. In previously infected individuals, a single dose boosted all humoral and T cell responses, with strong correlations between T helper and antibody immunity. Our results highlight the potential role of Fc-mediated effector functions and T cell responses in vaccine efficacy. They also provide support for spacing doses to vaccinate more individuals in conditions of vaccine scarcity.


Subject(s)
Antibodies, Viral/immunology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , COVID-19/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adult , Antibodies, Neutralizing/immunology , Antibodies, Viral/chemistry , Betacoronavirus , COVID-19/prevention & control , Carrier Proteins , Female , Humans , Immunity , Immunoglobulin Fc Fragments , Male , Middle Aged , Vaccination , Vaccines, Synthetic/immunology , Young Adult
17.
J Clin Invest ; 131(8)2021 04 15.
Article in English | MEDLINE | ID: covidwho-1186423

ABSTRACT

Dysregulated immune profiles have been described in symptomatic patients infected with SARS-CoV-2. Whether the reported immune alterations are specific to SARS-CoV-2 infection or also triggered by other acute illnesses remains unclear. We performed flow cytometry analysis on fresh peripheral blood from a consecutive cohort of (a) patients hospitalized with acute SARS-CoV-2 infection, (b) patients of comparable age and sex hospitalized for another acute disease (SARS-CoV-2 negative), and (c) healthy controls. Using both data-driven and hypothesis-driven analyses, we found several dysregulations in immune cell subsets (e.g., decreased proportion of T cells) that were similarly associated with acute SARS-CoV-2 infection and non-COVID-19-related acute illnesses. In contrast, we identified specific differences in myeloid and lymphocyte subsets that were associated with SARS-CoV-2 status (e.g., elevated proportion of ICAM-1+ mature/activated neutrophils, ALCAM+ monocytes, and CD38+CD8+ T cells). A subset of SARS-CoV-2-specific immune alterations correlated with disease severity, disease outcome at 30 days, and mortality. Our data provide an understanding of the immune dysregulation specifically associated with SARS-CoV-2 infection among acute care hospitalized patients. Our study lays the foundation for the development of specific biomarkers to stratify SARS-CoV-2-positive patients at risk of unfavorable outcomes and to uncover candidate molecules to investigate from a therapeutic perspective.


Subject(s)
COVID-19/immunology , Leukocytes/classification , Leukocytes/immunology , SARS-CoV-2 , Acute Disease , Adult , Aged , B-Lymphocyte Subsets/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/epidemiology , COVID-19/mortality , Case-Control Studies , Cohort Studies , Female , Hospitalization , Humans , Lymphocyte Activation , Male , Middle Aged , Models, Immunological , Monocytes/immunology , Multivariate Analysis , Neutrophils/immunology , Pandemics , Prognosis , Prospective Studies , Quebec/epidemiology , Risk Factors , SARS-CoV-2/immunology , Severity of Illness Index
18.
Cell Rep ; 34(9): 108790, 2021 03 02.
Article in English | MEDLINE | ID: covidwho-1077816

ABSTRACT

Characterization of the humoral response to SARS-CoV-2, the etiological agent of COVID-19, is essential to help control the infection. The neutralization activity of plasma from patients with COVID-19 decreases rapidly during the first weeks after recovery. However, the specific role of each immunoglobulin isotype in the overall neutralizing capacity is still not well understood. In this study, we select plasma from a cohort of convalescent patients with COVID-19 and selectively deplete immunoglobulin A, M, or G before testing the remaining neutralizing capacity of the depleted plasma. We find that depletion of immunoglobulin M is associated with the most substantial loss of virus neutralization, followed by immunoglobulin G. This observation may help design efficient antibody-based COVID-19 therapies and may also explain the increased susceptibility to SARS-CoV-2 of autoimmune patients receiving therapies that impair the production of immunoglobulin M (IgM).


Subject(s)
COVID-19/therapy , Immunoglobulin M/immunology , Immunoglobulin M/therapeutic use , SARS-CoV-2/immunology , Adult , Aged , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/epidemiology , COVID-19/immunology , Canada/epidemiology , Cohort Studies , Female , Humans , Immunity, Humoral/immunology , Immunization, Passive/methods , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/blood , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , Young Adult
19.
Cell Host Microbe ; 28(6): 880-891.e8, 2020 12 09.
Article in English | MEDLINE | ID: covidwho-921850

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) mediates viral entry into cells and is critical for vaccine development against coronavirus disease 2019 (COVID-19). Structural studies have revealed distinct conformations of S, but real-time information that connects these structures is lacking. Here we apply single-molecule fluorescence (Förster) resonance energy transfer (smFRET) imaging to observe conformational dynamics of S on virus particles. Virus-associated S dynamically samples at least four distinct conformational states. In response to human receptor angiotensin-converting enzyme 2 (hACE2), S opens sequentially into the hACE2-bound S conformation through at least one on-path intermediate. Conformational preferences observed upon exposure to convalescent plasma or antibodies suggest mechanisms of neutralization involving either competition with hACE2 for binding to the receptor-binding domain (RBD) or allosteric interference with conformational changes required for entry. Our findings inform on mechanisms of S recognition and conformations for immunogen design.


Subject(s)
COVID-19/genetics , Protein Conformation , SARS-CoV-2/ultrastructure , Spike Glycoprotein, Coronavirus/ultrastructure , Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Epitopes/immunology , Humans , Membrane Glycoproteins/genetics , Membrane Glycoproteins/ultrastructure , Protein Binding/immunology , Receptors, Virus/genetics , Receptors, Virus/immunology , Receptors, Virus/ultrastructure , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Virion/genetics , Virion/ultrastructure , Virus Internalization
20.
Viruses ; 12(10)2020 09 29.
Article in English | MEDLINE | ID: covidwho-904976

ABSTRACT

Severe acute respiratory syndrome virus 2 (SARS-CoV-2) is responsible for the current global coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The viral entry of SARS-CoV-2 depends on an interaction between the receptor-binding domain of its trimeric spike glycoprotein and the human angiotensin-converting enzyme 2 (ACE2) receptor. A better understanding of the spike/ACE2 interaction is still required to design anti-SARS-CoV-2 therapeutics. Here, we investigated the degree of cooperativity of ACE2 within both the SARS-CoV-2 and the closely related SARS-CoV-1 membrane-bound S glycoproteins. We show that there exist differential inter-protomer conformational transitions between both spike trimers. Interestingly, the SARS-CoV-2 spike exhibits a positive cooperativity for monomeric soluble ACE2 binding when compared to the SARS-CoV-1 spike, which might have more structural restraints. Our findings can be of importance in the development of therapeutics that block the spike/ACE2 interaction.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/metabolism , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/metabolism , SARS Virus/physiology , Severe Acute Respiratory Syndrome/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2 , Betacoronavirus/metabolism , COVID-19 , Carrier Proteins , Coronavirus Infections/virology , Cryoelectron Microscopy , HEK293 Cells , Humans , Pandemics , Pneumonia, Viral/virology , Protein Binding , Protein Interaction Domains and Motifs , SARS Virus/metabolism , SARS-CoV-2 , Severe Acute Respiratory Syndrome/virology , Virus Internalization
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