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1.
Current Topics in Pharmacology ; 26:39-47, 2022.
Article in English | EMBASE | ID: covidwho-20243739

ABSTRACT

This study compares the serological antibody level post-COVID-19 vaccine among healthy subjects and psychiatric patients on antidepressant therapy. It also examines the difference in antidepressants' side effects experienced by psychiatric patients following the completion of two vaccine doses. A comparative posttest quasi-experimental study was conducted among healthy subjects and psychiatric patients on antidepressant medication in a teaching hospital in Malaysia. Elecsys Anti-SARS-CoV-2 assay was used to detect the antibody titre between weeks 4 and 12 post vaccination. The antidepressant side-effect checklist (ASEC) was used to monitor the occurrence of antidepressant-related side effects pre-and post-vaccination. 24 psychiatric patients and 26 healthy subjects were included. There was no significant difference in the antibody level between the patients (median = 1509 u/ml) and the healthy subjects (median = 995 u/ml). There was no significant worsening in the antidepressant-related side effects. The antibody level post-COVID-19 vaccine did not differ significantly between patients on antidepressant therapy and healthy subjects. Additionally, there was no change in the antidepressant side effects experienced by the patients following the completion of the vaccine.Copyright © 2022, Research Trends (P) LTD.. All rights reserved.

2.
BIOpreparations ; Prevention, Diagnosis, Treatment. 23(1):76-89, 2023.
Article in Russian | EMBASE | ID: covidwho-20234832

ABSTRACT

Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies. The aim of the study was to obtain and characterise a SARSCoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies. Material(s) and Method(s): the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved monoclonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones. Result(s): the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD's ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30-50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies. Conclusion(s): the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein.Copyright © 2023 Authors. All rights reserved.

3.
Germs ; 12(4):507-518, 2022.
Article in English | EMBASE | ID: covidwho-20234801

ABSTRACT

Introduction In this study, we aimed to monitor anti-spike and anti-nucleocapsid antibodies positivity in healthcare workers (HCWs) vaccinated with two doses of inactivated CoronaVac (Sinovac, China) vaccine. Methods Overall, 242 volunteer HCWs were included. Of the participants, 193 were HCWs without history of prior documented COVID-19 (Group 1), while 49 had history of prior documented COVID-19 before vaccination (Group 2). The participants were followed up for SARS-CoV-2 antibodies positivity at four different blood sampling time points (immediately before the second vaccine dose and at the 1st, 3rd months and 141-150 days after the second dose). We investigated the serum IgG class antibodies against SARS-CoV-2 RBD region and IgG class antibodies against SARS-CoV-2 nucleocapsid antigen by chemiluminescent microparticle immunoassay (CMIA) method using commercial kits. Results We found positive serum anti-RBD IgG antibody in 76.4% of the participants (71% in Group 1;98% in Group 2) 28 days after the first dose. When the antibody levels of the groups were compared at the four blood sampling time points, Group 2 anti-RBD IgG levels were found to be significantly higher than those in Group 1 at all follow-up time points. Although anti-RBD IgG positivity persisted in 95.6% of all participants in the last blood sampling time point, a significant decrease was observed in antibody levels compared to the previous blood sampling time point. Anti-nucleocapsid IgG antibody was positive in 12 (6.2%) of participants in Group 1 and 32 (65.3%) in Group 2 at day 28 after the first dose. At the fourth blood sampling time point, anti-nucleocapsid antibodies were found to be positive in a total of 20 (9.7%) subjects, 10 (6.1%) in Group 1 and 10 (23.8%) in Group 2. Conclusions In this study, it was determined that serum antibody levels decreased in both groups after the third month after the second dose in HCWs vaccinated with CoronaVac vaccine.Copyright © GERMS 2022.

4.
Journal of Clinical Investigation ; 133(1), 2023.
Article in English | Web of Science | ID: covidwho-20231847

ABSTRACT

Infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and vaccinations targeting the spike protein (S) offer protective immunity against coronavirus disease 2019 (COVID-19). This immunity may further be shaped by cross reactivity with common cold coronaviruses. Mutations arising in S that are associated with altered intrinsic virus properties and immune escape result in the continued circulation of SARS-CoV-2 variants. Potentially, vaccine updates will be required to protect against future variants of concern, as for influenza. To offer potent protection against future variants, these second-generation vaccines may need to redirect immunity to epitopes associated with immune escape and not merely boost immunity toward conserved domains in preimmune individuals. For influenza, efficacy of repeated vaccination is hampered by original antigenic sin, an attribute of immune memory that leads to greater induction of antibodies specific to the first-encountered variant of an immunogen compared with subsequent variants. In this Review, recent findings on original antigenic sin are discussed in the context of SARS-CoV-2 evolution. Unanswered questions and future directions are highlighted, with an emphasis on the impact on disease outcome and vaccine design.

5.
Int J Mol Sci ; 24(10)2023 May 15.
Article in English | MEDLINE | ID: covidwho-20233610

ABSTRACT

Though the bulk of the COVID-19 pandemic is behind, the search for effective and safe anti-SARS-CoV-2 drugs continues to be relevant. A highly pursued approach for antiviral drug development involves targeting the viral spike (S) protein of SARS-CoV-2 to prevent its attachment to the cellular receptor ACE2. Here, we exploited the core structure of polymyxin B, a naturally occurring antibiotic, to design and synthesize unprecedented peptidomimetics (PMs), intended to target contemporarily two defined, non-overlapping regions of the S receptor-binding domain (RBD). Monomers 1, 2, and 8, and heterodimers 7 and 10 bound to the S-RBD with micromolar affinity in cell-free surface plasmon resonance assays (KD ranging from 2.31 µM to 2.78 µM for dimers and 8.56 µM to 10.12 µM for monomers). Although the PMs were not able to fully protect cell cultures from infection with authentic live SARS-CoV-2, dimer 10 exerted a minimal but detectable inhibition of SARS-CoV-2 entry in U87.ACE2+ and A549.ACE2.TMPRSS2+ cells. These results validated a previous modeling study and provided the first proof-of-feasibility of using medium-sized heterodimeric PMs for targeting the S-RBD. Thus, heterodimers 7 and 10 may serve as a lead for the development of optimized compounds, which are structurally related to polymyxin, with improved S-RBD affinity and anti-SARS-CoV-2 potential.


Subject(s)
COVID-19 , Peptidomimetics , Humans , SARS-CoV-2 , Peptidomimetics/pharmacology , Binding Sites , Angiotensin-Converting Enzyme 2/chemistry , Polymyxins , Pandemics , Protein Binding
6.
Microbiol Spectr ; : e0119023, 2023 Jun 12.
Article in English | MEDLINE | ID: covidwho-20236977

ABSTRACT

The continuous emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made it challenging to develop broad-spectrum prophylactic vaccines and therapeutic antibodies. Here, we have identified a broad-spectrum neutralizing antibody and its highly conserved epitope in the receptor-binding domain (RBD) of the spike protein (S) S1 subunit of SARS-CoV-2. First, nine monoclonal antibodies (MAbs) against the RBD or S1 were generated; of these, one RBD-specific MAb, 22.9-1, was selected for its broad RBD-binding abilities and neutralizing activities against SARS-CoV-2 variants. An epitope of 22.9-1 was fine-mapped with overlapping and truncated peptide fusion proteins. The core sequence of the epitope, 405D(N)EVR(S)QIAPGQ414, was identified on the internal surface of the up-state RBD. The epitope was conserved in nearly all variants of concern of SARS-CoV-2. MAb 22.9-1 and its novel epitope could be beneficial for research on broad-spectrum prophylactic vaccines and therapeutic antibody drugs. IMPORTANCE The continuous emergence of new variants of SARS-CoV-2 has caused great challenge in vaccine design and therapeutic antibody development. In this study, we selected a broad-spectrum neutralizing mouse monoclonal antibody which recognized a conserved linear B-cell epitope located on the internal surface of RBD. This MAb could neutralize all variants until now. The epitope was conserved in all variants. This work provides new insights in developing broad-spectrum prophylactic vaccines and therapeutic antibodies.

7.
Biotechnol J ; : e2300130, 2023 Jun 10.
Article in English | MEDLINE | ID: covidwho-20244872

ABSTRACT

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused considerable morbidity and mortality worldwide. Although authorized COVID-19 vaccines have been shown highly effective, their significantly lower efficacy against heterologous variants, and the rapid decrease of vaccine-elicited immunity raises serious concerns, calling for improved vaccine tactics. To this end, a pseudovirus nanoparticle (PVNP) displaying the receptor binding domains (RBDs) of SARS-CoV-2 spike, named S-RBD, was generated and shown it as a promising COVID-19 vaccine candidate. The S-RBD PVNP was produced using both prokaryotic and eukaryotic systems. A 3D structural model of the S-RBD PVNPs was built based on the known structures of the S60 particle and RBDs, revealing an S60 particle-based icosahedral symmetry with multiple surface-displayed RBDs that retain authentic conformations and receptor-binding functions. The PVNP is highly immunogenic, eliciting high titers of RBD-specific IgG and neutralizing antibodies in mice. The S-RBD PVNP demonstrated exceptional protective efficacy, and fully (100%) protected K18-hACE2 mice from mortality and weight loss after a lethal SARS-CoV-2 challenge, supporting the S-RBD PVNPs as a potent COVID-19 vaccine candidate. By contrast, a PVNP displaying the N-terminal domain (NTD) of SARS-CoV-2 spike exhibited only 50% protective efficacy. Since the RBD antigens of our PVNP vaccine are adjustable as needed to address the emergence of future variants, and various S-RBD PVNPs can be combined as a cocktail vaccine for broad efficacy, these non-replicating PVNPs offer a flexible platform for a safe, effective COVID-19 vaccine with minimal manufacturing cost and time.

8.
Recent Pat Biotechnol ; 2023 May 23.
Article in English | MEDLINE | ID: covidwho-20242464

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a viral respiratory disease that is associated with severe damage to other human organs. It causes by a novel coronavirus, and it is spreading all over the world. To date, there is some approved vaccine or therapeutic agent which could be effective against this disease. But their effectiveness against mutated strains is not studied completely. The spike glycoprotein on the surface of the coronaviruses gives the virus the ability to bind to host cell receptors and enter cells. Inhibition of attachment of these spikes can lead to virus neutralization by inhibiting viral entrance. AIMS: In this study, we tried to use the virus entrance strategy against itself by utilizing virus receptor (ACE-2) in order to design an engineered protein consisting of a human Fc antibody fragment and a part of ACE-2, which reacts with virus RBD, and we also evaluated this interaction by computational methods and in silico methods. Subsequently, we have designed a new protein structure to bind with this site and inhibit the virus from attaching to its cell receptor, mechanically or chemically. METHODS: Various in silico software and bioinformatic databases were used to retrieve the requested gene and protein sequences. The physicochemical properties and possibility of allergenicity were also examined. Three-dimensional structure prediction and molecular docking were also performed to develop the most suitable therapeutic protein. RESULTS: The designed protein consisted of a total of 256 amino acids with a molecular weight of 28984.62 and 5.92 as a theoretical isoelectric point. Instability and aliphatic index and grand average of hydropathicity are 49.99, 69.57 and -0.594, respectively. CONCLUSIONS: In silico studies can provide a good opportunity to study viral proteins and new drugs or compounds since they do not need direct exposure to infectious agents or equipped laboratories. The suggested therapeutic agent should be further characterized in vitro and in vivo.

9.
Heliyon ; 9(6): e16847, 2023 Jun.
Article in English | MEDLINE | ID: covidwho-20230952

ABSTRACT

The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused millions of cases of infections, leading to a global health emergency. The SARS-CoV-2 spike (S) protein plays the most important role in viral infection, and S1 subunit and its receptor-binding domain (RBD) are widely considered the most attractive vaccine targets. The RBD is highly immunogenic and its linear epitopes are important for vaccine development and therapy, but linear epitopes on the RBD have rarely been reported. In this study, 151 mouse monoclonal antibodies (mAbs) against the SARS-CoV-2 S1 protein were characterized and used to identify epitopes. Fifty-one mAbs reacted with eukaryotic SARS-CoV-2 RBD. Sixty-nine mAbs reacted with the S proteins of Omicron variants B.1.1.529 and BA.5, indicating their potential as rapid diagnostic materials. Three novel linear epitopes of RBD, R6 (391CFTNVYADSFVIRGD405), R12 (463PFERDISTEIYQAGS477), and R16 (510VVVLSFELLHAPAT523), were identified; these were highly conserved in SARS-CoV-2 variants of concern and could be detected in the convalescent serum of COVID-19 patients. From pseudovirus neutralization assays, some mAbs including one detecting R12 were found to possess neutralizing activity. Together, from the reaction of mAbs with eukaryotic RBD (N501Y), RBD (E484K), and S1 (D614G), we found that a single amino acid mutation in the SARS-CoV-2 S protein may cause a structural alteration, exerting substantial impact on mAb recognition. Our results could, therefore, help us better understand the function of the SARS-CoV-2 S protein and develop diagnostic tools for COVID-19.

10.
Front Immunol ; 14: 1160283, 2023.
Article in English | MEDLINE | ID: covidwho-20230711

ABSTRACT

Introduction: The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been posing a severe threat to global public health. Although broadly neutralizing antibodies have been used to prevent or treat corona virus disease 2019 (COVID-19), new emerging variants have been proven resistant to these antibodies. Methods: In this study, we isolated receptor binding domain (RBD)-specific memory B cells using single-cell sorting method from two COVID-19 convalescents and expressed the antibody to test their neutralizing activity against diverse SARS-CoV-2 variants. Then, we resolved antibody-RBD complex structures of potent RBD-specific neutralizing antibodies by X-ray diffraction method. Finally, we analyzed the whole antibody repertoires of the two donors and studied the evolutionary pathway of potent neutralizing antibodies. Results and discussion: We identified three potent RBD-specific neutralizing antibodies (1D7, 3G10 and 3C11) from two COVID-19 convalescents that neutralized authentic SARS-CoV-2 WH-1 and Delta variant, and one of them, 1D7, presented broadly neutralizing activity against WH-1, Beta, Gamma, Delta and Omicron authentic viruses. The resolved antibody-RBD complex structures of two antibodies, 3G10 and 3C11, indicate that both of them interact with the external subdomain of the RBD and that they belong to the RBD-1 and RBD-4 communities, respectively. From the antibody repertoire analysis, we found that the CDR3 frequencies of the light chain, which shared high degrees of amino acid identity with these three antibodies, were higher than those of the heavy chain. This research will contribute to the development of RBD-specific antibody-based drugs and immunogens against multiple variants.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Broadly Neutralizing Antibodies , Antibodies, Neutralizing
11.
Cell Rep ; 42(6): 112621, 2023 May 26.
Article in English | MEDLINE | ID: covidwho-2327607

ABSTRACT

Continued evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is eroding antibody responses elicited by prior vaccination and infection. The SARS-CoV-2 receptor-binding domain (RBD) E406W mutation abrogates neutralization mediated by the REGEN-COV therapeutic monoclonal antibody (mAb) COVID-19 cocktail and the AZD1061 (COV2-2130) mAb. Here, we show that this mutation remodels the receptor-binding site allosterically, thereby altering the epitopes recognized by these three mAbs and vaccine-elicited neutralizing antibodies while remaining functional. Our results demonstrate the spectacular structural and functional plasticity of the SARS-CoV-2 RBD, which is continuously evolving in emerging SARS-CoV-2 variants, including currently circulating strains that are accumulating mutations in the antigenic sites remodeled by the E406W substitution.

12.
BIOpreparations ; Prevention, Diagnosis, Treatment. 23(1):76-89, 2023.
Article in Russian | EMBASE | ID: covidwho-2322749

ABSTRACT

Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies. The aim of the study was to obtain and characterise a SARSCoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies. Material(s) and Method(s): the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved monoclonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones. Result(s): the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD's ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30-50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies. Conclusion(s): the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein.Copyright © 2023 Authors. All rights reserved.

13.
J Pharm Anal ; 2023 May 22.
Article in English | MEDLINE | ID: covidwho-2327241

ABSTRACT

Currently, human health due to corona virus disease 2019 (COVID-19) pandemic has been seriously threatened. The coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein plays a crucial role in virus transmission and several S-based therapeutic approaches have been approved for the treatment of COVID-19. However, the efficacy is compromised by the SARS-CoV-2 evolvement and mutation. Here we report the SARS-CoV-2 S protein receptor-binding domain (RBD) inhibitor licorice-saponin A3 (A3) could widely inhibit RBD of SARS-CoV-2 variants, including Beta, Delta, and Omicron BA.1, XBB and BQ1.1. Furthermore, A3 could potently inhibit SARS-CoV-2 Omicron virus in Vero E6 cells, with EC50 of 1.016 µM. The mechanism was related with binding with Y453 of RBD determined by hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis combined with quantum mechanics/molecular mechanics (QM/MM) simulations. Interestingly, phosphoproteomics analysis and multi fluorescent immunohistochemistry (mIHC) respectively indicated that A3 also inhibits host inflammation by directly modulating the JNK and p38 MAPK pathways and rebalancing the corresponding immune dysregulation. This work supports A3 as a promising broad-spectrum small molecule drug candidate for COVID-19.

14.
J Enzyme Inhib Med Chem ; 38(1): 2212327, 2023 Dec.
Article in English | MEDLINE | ID: covidwho-2323671

ABSTRACT

Both receptor-binding domain in spike protein (S-RBD) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human neuropilin-1 (NRP1) are important in the virus entry, and their concomitant inhibition may become a potential strategy against the SARS-CoV-2 infection. Herein, five novel dual S-RBD/NRP1-targeting peptides with nanomolar binding affinities were identified by structure-based virtual screening. Particularly, RN-4 was found to be the most promising peptide targeting S-RBD (Kd = 7.4 ± 0.5 nM) and NRP1-BD (the b1 domain of NRP1) (Kd = 16.1 ± 1.1 nM) proteins. Further evidence in the pseudovirus infection assay showed that RN-4 can significantly inhibit the SARS-CoV-2 pseudovirus entry into 293 T cells (EC50 = 0.39 ± 0.09 µM) without detectable side effects. These results suggest that RN-4, a novel dual S-RBD/NRP1-targeting agent, holds potential as an effective therapeutic to combat the SARS-CoV-2 infection.


Subject(s)
COVID-19 , Molecular Dynamics Simulation , Humans , SARS-CoV-2 , Neuropilin-1 , Peptides/pharmacology , Protein Binding
15.
BIOpreparations ; Prevention, Diagnosis, Treatment. 23(1):76-89, 2023.
Article in Russian | EMBASE | ID: covidwho-2314080

ABSTRACT

Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies. The aim of the study was to obtain and characterise a SARSCoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies. Material(s) and Method(s): the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved monoclonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones. Result(s): the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD's ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30-50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies. Conclusion(s): the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein.Copyright © 2023 Authors. All rights reserved.

16.
J Biomol Struct Dyn ; : 1-20, 2022 Mar 16.
Article in English | MEDLINE | ID: covidwho-2317280

ABSTRACT

The first direful biomolecular event leading to COVID-19 disease is the SARS-CoV-2 virus surface spike (S) protein-mediated interaction with the human transmembrane protein, angiotensin-converting enzyme 2 (hACE2). Prevention of this interaction presents an attractive alternative to thwart SARS-CoV-2 replications. The development of monoclonal antibodies (mAbs) in the convalescent plasma treatment, nanobody, and designer peptides, which recognizes epitopes that overlap with hACE2 binding sites in the receptor-binding domain (RBD) of S protein (S/RBD) and thereby blocking the infection has been the center stage of therapeutic research. Here we report atomistic and reliable in silico structure-energetic features of the S/RBD interactions with hACE2 and its two inhibitors (convalescent mAb, B38, and an alpaca nanobody, Ty1). The discovered potential of mean forces exhibits free energy basin and barriers along the interaction pathways, providing sufficient molecular insights to design a B38 mutant and a Ty1-based peptide with higher binding capacity. While the mutated B38 forms a 60-fold deeper free energy minimum, the designer peptide (Ty1-based) constitutes 38 amino acids and is found to form a 100-fold deeper free energy minimum in the first binding basin than their wild-type variants in complex with S/RBD. Our strategy may help to design more efficacious biologics towards therapeutic intervention against the current raging pandemic.Communicated by Ramaswamy H. Sarma.

17.
Mol Divers ; 2022 May 26.
Article in English | MEDLINE | ID: covidwho-2312123

ABSTRACT

SARS, or severe acute respiratory syndrome, is caused by a novel coronavirus (COVID-19). This situation has compelled many pharmaceutical R&D companies and public health research sectors to focus their efforts on developing effective therapeutics. SARS-nCoV-2 was chosen as a protein spike to targeted monoclonal antibodies and therapeutics for prevention and treatment. Deep mutational scanning created a monoclonal antibody to characterize the effects of mutations in a variable antibody fragment based on its expression levels, specificity, stability, and affinity for specific antigenic conserved epitopes to the Spike-S-Receptor Binding Domain (RBD). Improved contacts between Fv light and heavy chains and the targeted antigens of RBD could result in a highly potent neutralizing antibody (NAbs) response as well as cross-protection against other SARS-nCoV-2 strains. It undergoes multipoint core mutations that combine enhancing mutations, resulting in increased binding affinity and significantly increased stability between RBD and antibody. In addition, we improved. Structures of variable fragment (Fv) complexed with the RBD of Spike protein were subjected to our established in-silico antibody-engineering platform to obtain enhanced binding affinity to SARS-nCoV-2 and develop ability profiling. We found that the size and three-dimensional shape of epitopes significantly impacted the activity of antibodies produced against the RBD of Spike protein. Overall, because of the conformational changes between RBD and hACE2, it prevents viral entry. As a result of this in-silico study, the designed antibody can be used as a promising therapeutic strategy to treat COVID-19.

18.
Jpn J Infect Dis ; 2023 Apr 28.
Article in English | MEDLINE | ID: covidwho-2320258

ABSTRACT

Adverse events are potentially associated with an IgG response after the BNT162b2 vaccination for severe acute respiratory syndrome coronavirus 2. In this study, we investigated the side effects of BNT162b2 vaccination using a health questionnaire and examined its relationship with IgG antibody titers. Serum samples were collected from participants 3 months after the second vaccination, just before the third vaccination, and 1 and 3 months after the third vaccination. A total of 505 participants who received three doses of vaccination were eligible for analysis. The results showed that post-vaccination body temperature correlated with anti-spike-receptor-binding domain (anti-S-RBD) antibody titers analyzed 3 months after the second (r = 0.30, p < 0.001) and third (r = 0.14, p < 0.001) vaccinations. Multivariate linear regression analysis revealed that age and severe swelling were negatively associated with log-transformed anti-S-RBD antibody levels, whereas sex (female), body temperature, and heat sensation were positively associated after the second vaccination. After the third vaccination, body temperature, and fatigue were positively associated with log-transformed anti-S-RBD antibody levels, and sex (female) was negatively associated. These results indicate that post-vaccination fever may be a marker of increased antibody titer.

19.
Acta Naturae ; 15(1): 81-86, 2023.
Article in English | MEDLINE | ID: covidwho-2318683

ABSTRACT

The new coronavirus infection COVID-19 is an acute viral disease that affects primarily the upper respiratory tract. The etiological agent of COVID-19 is the SARS-CoV-2 RNA virus (Coronaviridae family, Betacoronavirus genus, Sarbecovirus subgenus). We have developed a high-affinity human monoclonal antibody, called C6D7-RBD, which is specific to the S protein receptor-binding domain (RBD) from the SARS-CoV-2 Wuhan-Hu-1 strain and exhibits virus-neutralizing activity in a test with recombinant antigens: angiotensin-converting enzyme 2 (ACE2) and RBD.

20.
Monoclon Antib Immunodiagn Immunother ; 42(2): 77-94, 2023 Apr.
Article in English | MEDLINE | ID: covidwho-2318494

ABSTRACT

Monoclonal antibodies (mAbs) had received emergency use authorization for mild-to-moderate coronavirus disease 2019 (COVID-19) or for prophylaxis against COVID-19, including casirivimab plus imdevimab (C+I), bamlanivimab plus etesevimab (B+E), tixagevimab plus cilgavimab (T+CG), and sotrovimab (S) and bebtelovimab (BEB). This systematic review was done to assess the efficacy and safety of the same. PubMed, Embase, Scopus, medRxiv, bioRxiv, and FDA fact sheets were searched for the studies published between January 2021 and May 2022, and appropriate search terms related to the mentioned mAbs were used for data collection. Review included original research including randomized clinical trials and observational studies published or preprints. Studies included in the review had compared with placebo or standard of care or no treatment or mAbs with each other and also of various doses. Data extraction was done and reviewed the same for both efficacy and safety. Total of 20 studies were included in this review. The rate of hospitalization within 30 days showed ∼2% in comparison to ∼7% with placebo. Significant reduction in viral load was more observed with combination mAbs. Combination therapy showed faster virological cure against the Gamma variant. With C + I as postexposure prophylaxis (PEP), 29.0% of asymptomatic participants developed symptomatic COVID-19. Pre-exposure prophylaxis with T+CG reduced the incidence of infection by 77%. Infusion-related reaction was the most common adverse event (AE). The neutralizing mAbs reduced hospitalization in mild-to-moderate patients with infusion-related reactions as common AE. The response was better in the seronegative patients. Most of these studies were conducted in unvaccinated individuals and against Alpha, Gamma, and Delta variants.


Subject(s)
Antibodies, Monoclonal , COVID-19 , Humans , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral
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