Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
1.
Commun Biol ; 5(1): 262, 2022 03 24.
Article in English | MEDLINE | ID: covidwho-1799550

ABSTRACT

Understanding the underlying molecular mechanisms behind ADE of SARS-CoV-2 is critical for development of safe and effective therapies. Here, we report that two neutralizing mAbs, MW01 and MW05, could enhance the infection of SARS-CoV-2 pseudovirus on FcγRIIB-expressing B cells. X-ray crystal structure determination and S trimer-binding modeling showed that MW01 and MW05 could bind to RBDs in S trimer with both "up" and "down" states. While, the neutralizing mAb MW07, which has no ADE activity only binds to RBD in S trimer with "up" state. Monovalent MW01 and MW05 completely diminished the ADE activity compared with their bivalent counterparts. Moreover, both macropinocytosis and endocytosis are confirmed involving in ADE of SARS-CoV-2 pseudoviral infection. Blocking endosome transportation and lysosome acidification could inhibit the ADE activity mediated by MW05. Together, our results identified a novel ADE mechanism of SARS-CoV-2 pseudovirus in vitro, FcγRIIB-mediated uptake of SARS-CoV-2/mAb complex with bivalent interaction.


Subject(s)
Antibody-Dependent Enhancement , COVID-19 , Antibodies, Viral , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
2.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-328783

ABSTRACT

Little is known of the role of cytotoxic CD4 + T-cells in the control of viral replication. Here, we investigate CD4 + T-cell responses to three dominant SARS-CoV-2 epitopes and evaluate antiviral activity, including cytotoxicity and antiviral cytokine production. Diverse T cell receptor (TCR) usage including public TCRs were identified;surprisingly, cytotoxic CD4 + T-cells were found to have signalling and cytotoxic pathways distinct from classical CD8 + T-cells, with increased expression of chemokines and tissue homing receptors promoting migration. We show the presence of cytolytic CD4 + T-cells during primary infection associates with COVID-19 disease severity. Robust immune memory 6-9 months post-infection or vaccination provides CD4 + T-cells with potent antiviral activity. Our data support a model where CD4 + killer cells drive immunopathogenesis during primary infection and CD4 + memory responses are protective during secondary infection. Our study highlights the unique features of cytotoxic CD4 + T-cells that use distinct functional pathways, providing preventative and therapeutic opportunities.

3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-309675

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, which has resulted in ~1,119,431 deaths. There is currently no approved vaccines or therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein promotes entry into host cells and is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target the SARS-CoV-2 Spike protein. One human antibody, CA521 LALA , demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521 LALA showed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro . The LALA mutation introduced to CA521 abrogates the binding with Fc receptors or complement receptors reducing antibody-dependent enhancement seen with anti-SARS-CoV antibodies. CA521 LALA also demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521 LALA inhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with the virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521 LALA recognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 receptor binding domain (RBD) in the Spike protein. CA521 LALA blocks the interaction by binding all three RBDs of one SARS CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions in the treatment of COVID-19 and identifies CA521 LALA a promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-309642

ABSTRACT

NP 105-113 -B*07:02 specific CD8 + T-cell responses are considered among the most dominant in SARS-CoV-2-infected individuals. We found strong association of this response with mild disease. Analysis of NP 105-113 -B*07:02 specific T-cell clones and single cell sequencing were performed concurrently, with functional avidity and anti-viral efficacy assessed using an in vitro SARS-CoV-2 infection system, and were correlated with TCR usage, transcriptome signature, and disease severity (acute N=77, convalescent N=52). We demonstrated a beneficial association of NP 105-113 -B*07:02 specific T-cells in COVID-19 disease progression, linked with expansion of T-cell precursors, high functional avidity and anti-viral effector function. Broad immune memory pools were narrowed post-infection but NP 105-113 -B*07:02 specific T-cells were maintained 6 months after infection with preserved anti-viral efficacy to the SARS-CoV-2 Victoria strain, as well as new Alpha, Beta and Gamma variants. Our data shows that NP 105-113 -B*07:02 specific T-cell responses associate with mild disease and high anti-viral efficacy, pointing to inclusion for future vaccine design.

5.
MAbs ; 14(1): 2005507, 2022.
Article in English | MEDLINE | ID: covidwho-1585297

ABSTRACT

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a serious public health crisis worldwide, and considering the novelty of the disease, preventative and therapeutic measures alike are urgently needed. To accelerate such efforts, the development of JS016, a neutralizing monoclonal antibody directed against the SARS-CoV-2 spike protein, was expedited from a typical 12- to 18-month period to a 4-month period. During this process, transient Chinese hamster ovary cell lines are used to support preclinical, investigational new drug-enabling toxicology research, and early Chemistry, Manufacturing and Controls development; mini-pool materials to supply Phase 1 clinical trials; and a single-clone working cell bank for late-stage and pivotal clinical trials were successively adopted. Moreover, key process performance and product quality investigations using a series of orthogonal and state-of-the-art techniques were conducted to demonstrate the comparability of products manufactured using these three processes, and the results indicated that, despite observed variations in process performance, the primary and high-order structures, purity and impurity profiles, biological and immunological functions, and degradation behaviors under stress conditions were largely comparable. The study suggests that, in particular situations, this strategy can be adopted to accelerate the development of therapeutic biopharmaceuticals and their access to patients.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/therapeutic use , Antibody Affinity/immunology , Antibody Specificity/immunology , CHO Cells , COVID-19/prevention & control , COVID-19/virology , Chromatography, High Pressure Liquid/methods , Circular Dichroism , Clone Cells , Cricetinae , Cricetulus , Humans , Immunoglobulin G/chemistry , Immunoglobulin G/immunology , Immunoglobulin G/therapeutic use , Isoelectric Point , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism
6.
Nat Immunol ; 23(1): 50-61, 2022 01.
Article in English | MEDLINE | ID: covidwho-1545628

ABSTRACT

NP105-113-B*07:02-specific CD8+ T cell responses are considered among the most dominant in SARS-CoV-2-infected individuals. We found strong association of this response with mild disease. Analysis of NP105-113-B*07:02-specific T cell clones and single-cell sequencing were performed concurrently, with functional avidity and antiviral efficacy assessed using an in vitro SARS-CoV-2 infection system, and were correlated with T cell receptor usage, transcriptome signature and disease severity (acute n = 77, convalescent n = 52). We demonstrated a beneficial association of NP105-113-B*07:02-specific T cells in COVID-19 disease progression, linked with expansion of T cell precursors, high functional avidity and antiviral effector function. Broad immune memory pools were narrowed postinfection but NP105-113-B*07:02-specific T cells were maintained 6 months after infection with preserved antiviral efficacy to the SARS-CoV-2 Victoria strain, as well as Alpha, Beta, Gamma and Delta variants. Our data show that NP105-113-B*07:02-specific T cell responses associate with mild disease and high antiviral efficacy, pointing to inclusion for future vaccine design.


Subject(s)
HLA-B7 Antigen/immunology , Immunodominant Epitopes/immunology , Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , T-Lymphocytes, Cytotoxic/immunology , Aged , Amino Acid Sequence , Antibodies, Viral/immunology , Antibody Affinity/immunology , COVID-19/immunology , COVID-19/pathology , Cell Line, Transformed , Female , Gene Expression Profiling , Humans , Immunologic Memory/immunology , Male , Middle Aged , Receptors, Antigen, T-Cell/immunology , Severity of Illness Index , Vaccinia virus/genetics , Vaccinia virus/immunology , Vaccinia virus/metabolism
7.
PLoS One ; 16(8): e0256352, 2021.
Article in English | MEDLINE | ID: covidwho-1360648

ABSTRACT

Rapid tests for SARS-COV-2 infection are important tools for pandemic control, but current rapid tests are based on proprietary designs and reagents. We report clinical validation results of an open-access lateral flow assay (OA-LFA) design using commercially available materials and reagents, along with RT-qPCR and commercially available comparators (BinaxNOW® and Sofia®). Adult patients with suspected COVID-19 based on clinical signs and symptoms, and with symptoms ≤7 days duration, underwent anterior nares (AN) sampling for the OA-LFA, Sofia®, BinaxNOW ™, and RT-qPCR, along with nasopharyngeal (NP) RT-qPCR. Results indicate a positive predictive agreement with NP sampling as 69% (60% -78%) OA-LFA, 74% (64% - 82%) Sofia®, and 82% (73% - 88%) BinaxNOW™. The implication for these results is that we provide an open-access LFA design that meets the minimum WHO target product profile for a rapid test, that virtually any diagnostic manufacturer could produce.


Subject(s)
Antigens, Viral/analysis , COVID-19/diagnosis , Immunoassay , SARS-CoV-2/metabolism , Area Under Curve , COVID-19/virology , Humans , Nasopharynx/virology , Point-of-Care Systems , RNA, Viral/analysis , RNA, Viral/metabolism , ROC Curve , Real-Time Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
8.
Emerg Microbes Infect ; 10(1): 1519-1529, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1316787

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutated continuously and newly emerging variants escape from antibody-mediated neutralization raised great concern. S protein is heavily glycosylated and the glycosylation sites are relatively conserved, thus glycans on S protein surface could be a target for the development of anti-SARS-CoV-2 strategies against variants. Here, we collected 12 plant-derived lectins with different carbohydrate specificity and evaluated their anti-SARS-CoV-2 activity against mutant strains and epidemic variants using a pseudovirus-based neutralization assay. The Lens culinaris-derived lentil lectin which specifically bind to oligomannose-type glycans and GlcNAc at the non-reducing end terminus showed most potent and broad antiviral activity against a panel of mutant strains and variants, including the artificial mutants at N-/O-linked glycosylation site, natural existed amino acid mutants, as well as the epidemic variants B.1.1.7, B.1.351, and P.1. Lentil lectin also showed antiviral activity against SARS-CoV and MERS-CoV. We found lentil lectin could block the binding of ACE2 to S trimer and inhibit SARS-CoV-2 at the early steps of infection. Using structural information and determined N-glycan profile of S trimer, taking together with the carbohydrate specificity of lentil lectin, we provide a basis for the observed broad spectrum anti-SARS-CoV-2 activity. Lentil lectin showed weak haemagglutination activity at 1 mg/mL and no cytotoxicity activity, and no weight loss was found in single injection mouse experiment. This report provides the first evidence that lentil lectin strongly inhibit infection of SARS-COV-2 variants, which should provide valuable insights for developing future anti-SARS-CoV-2 strategies.


Subject(s)
Antiviral Agents/pharmacology , Lens Plant/chemistry , Plant Extracts/pharmacology , Plant Lectins/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemistry , Humans , Mice , Mice, Inbred BALB C , Plant Extracts/chemistry , Plant Lectins/chemistry , SARS-CoV-2/growth & development , Seeds/chemistry
9.
Sustainability ; 13(10):5587, 2021.
Article in English | MDPI | ID: covidwho-1234814

ABSTRACT

In this study, we carry out a comparative analysis between the US and South Korea, with a special attention to three key areas, including the stock market, the currency market, and the bond market. By employing a composite model, VAR-GARCH-BEKK, we will attempt to capture both mean and volatility spillovers between the pandemic and financial markets, so as to explore the extent and ways in which the COVID-19 pandemic influences the financial sector. The empirical results provide substantial evidence in the following areas: (i) South Korea seems more vulnerable since all of its financial markets are seen to be statistically associated with the growth in infections. (ii) For the US, only the stock market is negatively impacted by the confirmed cases in terms of a conditional mean spillover model. (iii) According to the impulse response functions (IRFs), apart from the US dollar index, both the TED spread and stock returns respond significantly to innovations from the pandemic. (iv) There is little evidence to support the presence of volatility transmission from the pandemic to the financial markets in the two countries.

10.
Commun Biol ; 4(1): 500, 2021 04 23.
Article in English | MEDLINE | ID: covidwho-1213942

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic, which has resulted in more than two million deaths at 2021 February . There is currently no approved therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target SARS-CoV-2 Spike protein. One human antibody, CA521FALA, demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521FALA showed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro. CA521FALA also demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521FALA inhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521FALA recognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 RBD in the Spike protein. CA521FALA blocks the interaction by binding all three RBDs of one SARS-CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions against COVID-19 and identifies CA521FALA a promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies, Neutralizing/pharmacology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19/epidemiology , COVID-19/virology , Humans , Male , Mice, Inbred C57BL , Mice, Transgenic , Pandemics , Protein Binding/drug effects , Receptors, Virus/immunology , Receptors, Virus/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism
12.
Sci Rep ; 10(1): 16615, 2020 10 06.
Article in English | MEDLINE | ID: covidwho-834915

ABSTRACT

Middle East Respiratory Syndrome coronavirus (MERS-CoV) is a highly virulent pathogen that causes Middle East Respiratory Syndrome (MERS). Anti-MERS-CoV antibodies play an integral role in the prevention and treatment against MERS-CoV infections. Bioactivity is a key quality attribute of therapeutic antibodies, and high accuracy and precision are required. The major methods for evaluating the antiviral effect of antiviral antibodies include neutralization assays using live viruses or pseudoviruses are highly variable. Recent studies have demonstrated that the antibody-dependent cellular cytotoxicity (ADCC) activity of antiviral antibodies is more consistent with the virus clearance effect in vivo than neutralization activity. However, no reports evaluating the ADCC activity of anti-MERS antibodies have been published to date. Here, we describe the development of a robust and reliable cell-based reporter gene assay for the determination of ADCC activity of anti-MERS antibodies using 293T/MERS cells stably expressing the spike protein of MERS-CoV (MERS-S) as target cells and the engineered Jurkat/NFAT-luc/FcγRIIIa stably expressing FcγRIIIA and NFAT reporter gene as effector cells. According to the ICH-Q2 analytical method guidelines, we carefully optimized the experimental conditions and assessed the performance of our assay. In addition, we found that the ADCC activity of afucosylated anti-MERS antibodies is higher than their fucosylated counterparts. The establishment of this ADCC determination system provides a novel method for evaluating the bioactivity of anti-MERS antibodies and improving ADCC activity through modification of N-glycosylation of the Fc segment.


Subject(s)
Antibodies, Viral/analysis , Antibody-Dependent Cell Cytotoxicity/immunology , Coronavirus Infections/immunology , Cytotoxicity Tests, Immunologic/methods , Middle East Respiratory Syndrome Coronavirus/immunology , Middle East Respiratory Syndrome Coronavirus/metabolism , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Coronavirus Infections/virology , Genes, Reporter , HEK293 Cells , Humans , Jurkat Cells , Luciferases/genetics , Middle East Respiratory Syndrome Coronavirus/genetics , NFATC Transcription Factors/genetics , Receptors, IgG/genetics , Receptors, IgG/immunology , Response Elements , Spike Glycoprotein, Coronavirus/metabolism , Transfection
SELECTION OF CITATIONS
SEARCH DETAIL