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1.
J Med Chem ; 65(3): 2558-2570, 2022 02 10.
Article in English | MEDLINE | ID: covidwho-1895561

ABSTRACT

Safe and effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants are the best approach to successfully combat the COVID-19 pandemic. The receptor-binding domain (RBD) of the viral spike protein is a major target to develop candidate vaccines. α-Galactosylceramide (αGalCer), a potent invariant natural killer T cell (iNKT) agonist, was site-specifically conjugated to the N-terminus of the RBD to form an adjuvant-protein conjugate, which was anchored on the liposome surface. This is the first time that an iNKT cell agonist was conjugated to the protein antigen. Compared to the unconjugated RBD/αGalCer mixture, the αGalCer-RBD conjugate induced significantly stronger humoral and cellular responses. The conjugate vaccine also showed effective cross-neutralization to all variants of concern (B.1.1.7/alpha, B.1.351/beta, P.1/gamma, B.1.617.2/delta, and B.1.1.529/omicron). These results suggest that the self-adjuvanting αGalCer-RBD has great potential to be an effective COVID-19 vaccine candidate, and this strategy might be useful for designing various subunit vaccines.


Subject(s)
COVID-19 Vaccines/therapeutic use , COVID-19/therapy , Galactosylceramides/therapeutic use , Peptide Fragments/therapeutic use , SARS-CoV-2/immunology , Vaccines, Conjugate/therapeutic use , Adjuvants, Immunologic/chemistry , Adjuvants, Immunologic/therapeutic use , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Female , Galactosylceramides/chemistry , Galactosylceramides/immunology , Immunity, Humoral/drug effects , Immunity, Innate/drug effects , Interferon-gamma/metabolism , Liposomes/chemistry , Liposomes/immunology , Liposomes/therapeutic use , Mice, Inbred BALB C , Peptide Fragments/chemistry , Peptide Fragments/immunology , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/therapeutic use , Vaccines, Conjugate/chemistry , Vaccines, Conjugate/immunology
2.
Structure ; 30(5): 707-720.e5, 2022 05 05.
Article in English | MEDLINE | ID: covidwho-1829569

ABSTRACT

Because of the evolutionary variants of SARS-CoV-2, development of broad-spectrum neutralizing antibodies resilient to virus escape is urgently needed. We identified a group of high-affinity nanobodies from camels immunized with receptor-binding domain (RBD) of SARS-CoV-2 spike protein and resolved the structures of two non-competing nanobodies (NB1A7 and NB1B11) in complex with RBD using X-ray crystallography. The structures show that NB1A7 targets the highly conserved cryptic epitope shared by SARS-CoV-2 variants and some other coronaviruses and blocks ACE2 receptor attachment of the spike protein, and NB1B11 epitope overlaps with the contacting surface of ACE2 and is different from the binding site of NB1A7. These two nanobodies were covalently linked into multivalent and bi-paratopic formats, which significantly improved the avidity and neutralization potency and may further inhibit viral escape. The results contribute to the structure-guided design of antibodies against future variants of SARS-CoV-2 virus to combat coronavirus epidemics and pandemics.


Subject(s)
COVID-19 , Single-Domain Antibodies , Angiotensin-Converting Enzyme 2 , Antibodies, Neutralizing , Broadly Neutralizing Antibodies , Epitopes/metabolism , Humans , Protein Binding , SARS-CoV-2/genetics , Single-Domain Antibodies/chemistry , Single-Domain Antibodies/genetics , Spike Glycoprotein, Coronavirus/chemistry
3.
Chem Commun (Camb) ; 58(24): 3925-3928, 2022 Mar 22.
Article in English | MEDLINE | ID: covidwho-1730326

ABSTRACT

Adjuvants are important components in vaccines to increase the immunogenicity of proteins and induce optimal immunity. In this study, we designed a novel ternary adjuvant system Alum + c-GAMP + poly(I:C) with STING agonist 3,3'-c-GAMP (c-GAMP) and TLR3 agonist poly(I:C) co-adsorbed on the conventional adjuvant aluminum gel (Alum), and further constructed an S1 protein vaccine. Two doses of vaccination with the ternary adjuvant vaccine were sufficient to induce a balanced Th1/Th2 immune response and robust humoral and cellular immunity. Additionally, the ternary adjuvant group had effective neutralizing activity against live virus SARS-CoV-2 and pseudovirus of all variants of concern (alpha, beta, gamma, delta and omicron). These results indicate that the ternary adjuvants have a significant synergistic effect and can rapidly trigger potent immune responses; the combination of the ternary adjuvant system with S1 protein is a promising COVID-19 vaccine candidate.


Subject(s)
COVID-19 , SARS-CoV-2 , Adjuvants, Immunologic/pharmacology , Alum Compounds , Aluminum , Animals , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/pharmacology , Humans , Immunity, Cellular , Mice , Mice, Inbred BALB C , Poly I
4.
Chem Commun (Camb) ; 58(13): 2120-2123, 2022 Feb 10.
Article in English | MEDLINE | ID: covidwho-1639577

ABSTRACT

The coronavirus 2019 (COVID-19) pandemic is causing serious impacts in the world, and safe and effective vaccines and medicines are the best methods to combat the disease. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein plays a key role in interacting with the angiotensin-converting enzyme 2 (ACE2) receptor, and is regarded as an important target of vaccines. Herein, we constructed the adjuvant-protein conjugate Pam3CSK4-RBD as a vaccine candidate, in which the N-terminal of the RBD was site-selectively oxidized by transamination and conjugated with the TLR1/2 agonist Pam3CSK4. This demonstrated that the conjugation of Pam3CSK4 significantly enhanced the anti-RBD antibody response and cellular response. In addition, sera from the Pam3CSK4-RBD immunized group efficiently inhibited the binding of the RBD to ACE2 and protected cells from SARS-CoV-2 and four variants of concern (alpha, beta, gamma and delta), indicating that this adjuvant strategy could be one of the effective means for protein vaccine development.


Subject(s)
COVID-19/prevention & control , Lipopeptides/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Vaccines, Conjugate/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibody Formation , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , COVID-19/virology , Female , HEK293 Cells , Humans , Macrophages/cytology , Macrophages/immunology , Macrophages/metabolism , Mice , Mice, Inbred BALB C , Protein Binding , Protein Domains/immunology , RAW 264.7 Cells , Recombinant Proteins/biosynthesis , Recombinant Proteins/immunology , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Vaccines, Conjugate/administration & dosage , Vaccines, Conjugate/chemistry
5.
Nat Commun ; 12(1): 4887, 2021 08 09.
Article in English | MEDLINE | ID: covidwho-1349665

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that is spreading rapidly, which seriously impacts global public health and economy. Thus, developing effective drugs remains urgent. We identify two potent antibodies, nCoVmab1 and nCoVmab2, targeting the SARS-CoV-2 spike protein receptor-binding domain (RBD) with high affinities from a naïve human phage-displayed Fab library. nCoVmab1 and nCoVmab2 neutralize authentic SARS-CoV-2 with picomolar and nanomolar IC50 values, respectively. No detectable defects of nCoVmab1 and nCoVmab2 are found during the preliminary druggability evaluation. nCoVmab1 could reduce viral titer and lung injury when administered prophylactically and therapeutically in human angiotensin-converting enzyme II (hACE2)-transgenic mice. Therefore, phage display platform could be efficiently used for rapid development of neutralizing monoclonal antibodies (nmabs) with clinical potential against emerging infectious diseases. In addition, we determinate epitopes in RBD of these antibodies to elucidate the neutralizing mechanism. We also convert nCoVmab1 and nCoVmab2 to their germline formats for further analysis, which reveals the contribution of somatic hypermutation (SHM) during nCoVmab1 and nCoVmab2 maturation. Our findings not only provide two highly potent nmabs against SARS-CoV-2 as prophylactic and therapeutic candidates, but also give some clues for development of anti-SARS-CoV-2 agents (e.g., drugs and vaccines) targeting the RBD.


Subject(s)
Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , COVID-19/drug therapy , SARS-CoV-2/drug effects , Angiotensin-Converting Enzyme 2/genetics , Animals , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Binding Sites , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Chlorocebus aethiops , Epitopes/immunology , Humans , Male , Mice , Mice, Transgenic , Protein Binding , Receptors, Virus/drug effects , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus , Vero Cells
6.
J Chem Inf Model ; 61(8): 3917-3926, 2021 08 23.
Article in English | MEDLINE | ID: covidwho-1317793

ABSTRACT

The continual spread of novel coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), posing a severe threat to the health worldwide. The main protease (Mpro, alias 3CLpro) of SARS-CoV-2 is a crucial enzyme for the maturation of viral particles and is a very attractive target for designing drugs to treat COVID-19. Here, we propose a multiple conformation-based virtual screening strategy to discover inhibitors that can target SARS-CoV-2 Mpro. Based on this strategy, nine Mpro structures and a protein mimetics library with 8960 commercially available compounds were prepared to carry out ensemble docking for the first time. Five of the nine structures are apo forms presented in different conformations, whereas the other four structures are holo forms complexed with different ligands. The surface plasmon resonance assay revealed that 6 out of 49 compounds had the ability to bind to SARS-CoV-2 Mpro. The fluorescence resonance energy transfer experiment showed that the biochemical half-maximal inhibitory concentration (IC50) values of the six compounds could hamper Mpro activities ranged from 0.69 ± 0.05 to 2.05 ± 0.92 µM. Evaluation of antiviral activity using the cell-based assay indicated that two compounds (Z1244904919 and Z1759961356) could strongly inhibit the cytopathic effect and reduce replication of the living virus in Vero E6 cells with the half-maximal effective concentrations (EC50) of 4.98 ± 1.83 and 8.52 ± 0.92 µM, respectively. The mechanism of the action for the two inhibitors were further elucidated at the molecular level by molecular dynamics simulation and subsequent binding free energy analysis. As a result, the discovered noncovalent reversible inhibitors with novel scaffolds are promising antiviral drug candidates, which may be used to develop the treatment of COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Antiviral Agents/pharmacology , Cysteine Endopeptidases , Humans , Molecular Docking Simulation , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins
7.
iScience ; 24(4): 102293, 2021 Apr 23.
Article in English | MEDLINE | ID: covidwho-1203085

ABSTRACT

Recently, COVID-19 caused by the novel coronavirus SARS-CoV-2 has brought great challenges to the world. More and more studies have shown that patients with severe COVID-19 may suffer from cytokine storm syndrome; however, there are few studies on its pathogenesis. Here we demonstrated that SARS-CoV-2 coding protein open reading frame 8 (ORF8) acted as a contributing factor to cytokine storm during COVID-19 infection. ORF8 could activate IL-17 signaling pathway and promote the expression of pro-inflammatory factors. Moreover, we demonstrated that treatment of IL17RA antibody protected mice from ORF8-induced inflammation. Our findings are helpful to understand the pathogenesis of cytokine storm caused by SARS-CoV-2 and provide a potential target for the development of COVID-19 therapeutic drugs.

8.
Chem Biol Drug Des ; 98(1): 1-18, 2021 07.
Article in English | MEDLINE | ID: covidwho-1201241

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global health concern and pose a serious threat to humanity. There is an urgent need for developing therapeutic drugs and (or) biologics to prevent the spread of the virus. The life cycle of SARS-CoV-2 shows that the virus enters host cells by first binding to angiotensin-converting enzyme 2 (ACE2) through its spike protein receptor-binding domain (RBD). Therefore, blocking the binding between of ACE2 and SARS-CoV-2 RBD can inhibit the virus infection in the host cells. In this study, by grafting the complementarity-determining regions (CDRs) of developed SARS-CoV, MERS-CoVs specific neutralizing antibodies (nAbs) include monoclonal antibodies (mAbs) as well as SARS-CoV-2 mAbs onto a known stable nanobody (Nb) scaffold, and a total of 16 Nbs sequences were designed. Five Nbs, namely CS01, CS02, CS03, CS10, and CS16, were selected based on the free energy landscape of protein docking verified by the recently reported Nb-RBD cocrystal structures. CS01, CS02, and CS03 occupied the ACE2 binding site of RBD, while CS10 and CS16 were proposed to inhibit the interaction between RBD and ACE2 through an allosteric mechanism. Based on the structures of the five Nbs in complex with RBD, seven brand-new Nbs with enhanced binding affinities (CS02_RD01, CS03_RD01, CS03_RD02, CS03_RD03, CS03_RD04, CS16_RD01, and CS16_RD02) were generated by redesign of residues on the interface of the five Nbs contact with SARS-CoV-2 RBD. In addition, the identified "hot spots" on the interface of each complex provide useful information to understand the binding mechanism of designed Nbs to SARS-CoV-2 RBD. In sum, the predicted stabilities and high binding affinities of the 11 (re)designed Nbs indicating the potential of the developed computational framework in this work to design effective agents to block the infection of SARS-CoV-2.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , COVID-19 , Molecular Dynamics Simulation , SARS-CoV-2/chemistry , Single-Domain Antibodies/chemistry , Angiotensin-Converting Enzyme 2/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Humans , Protein Domains , SARS-CoV-2/immunology , Single-Domain Antibodies/immunology
9.
MedComm (2020) ; 2(1): 101-113, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1121801

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has become a serious burden on global public health. Although therapeutic drugs against COVID-19 have been used in many countries, their efficacy is still limited. We here reported nanobody (Nb) phage display libraries derived from four camels immunized with the SARS-CoV-2 spike receptor-binding domain (RBD), from which 381 Nbs were identified to recognize SARS-CoV-2-RBD. Furthermore, seven Nbs were shown to block interaction of human angiotensin-converting enzyme 2 (ACE2) with SARS-CoV-2-RBD variants and two Nbs blocked the interaction of human ACE2 with bat-SL-CoV-WIV1-RBD and SARS-CoV-1-RBD. Among these candidates, Nb11-59 exhibited the highest activity against authentic SARS-CoV-2 with 50% neutralizing dose (ND50) of 0.55 µg/ml. Nb11-59 can be produced on large scale in Pichia pastoris, with 20 g/L titer and 99.36% purity. It also showed good stability profile, and nebulization did not impact its stability. Overall, Nb11-59 might be a promising prophylactic and therapeutic molecule against COVID-19, especially through inhalation delivery.

10.
Sci Bull (Beijing) ; 66(7): 720-726, 2021 Apr 15.
Article in English | MEDLINE | ID: covidwho-1003043

ABSTRACT

Fully inactivating SARS-CoV-2, the virus causing coronavirus disease 2019, is of key importance for interrupting virus transmission but is currently performed by using biologically or environmentally hazardous disinfectants. Herein, we report an eco-friendly and efficient electrochemical strategy for inactivating the SARS-CoV-2 using in-situ formed nickel oxide hydroxide as anode catalyst and sodium carbonate as electrolyte. At a voltage of 5 V, the SARS-CoV-2 viruses can be rapidly inactivated with disinfection efficiency reaching 95% in only 30 s and 99.99% in 5 min. Mass spectrometry analysis and theoretical calculations indicate that the reactive oxygen species generated on the anode can oxidize the peptide chains and induce cleavage of the peptide backbone of the receptor binding domain of the SARS-CoV-2 spike glycoprotein, and thereby disables the virus. This strategy provides a sustainable and highly efficient approach for the disinfection of the SARS-CoV-2 viruliferous aerosols and wastewater.

11.
Brain Behav Immun ; 88: 916-919, 2020 08.
Article in English | MEDLINE | ID: covidwho-6139

ABSTRACT

Since December 2019, more than 79,000 people have been diagnosed with infection of the Corona Virus Disease 2019 (COVID-19). A large number of medical staff was sent to Wuhan city and Hubei province to aid COVID-19 control. Psychological stress, especially vicarious traumatization caused by the COVID-19 pandemic, should not be ignored. To address this concern, the study employed a total of 214 general public and 526 nurses (i.e., 234 front-line nurses and 292 non-front-line nurses) to evaluate vicarious traumatization scores via a mobile app-based questionnaire. Front-line nurses are engaged in the process of providing care for patients with COVID-19. The results showed that the vicarious traumatization scores for front-line nurses including scores for physiological and psychological responses, were significantly lower than those of non-front-line nurses (P < 0.001). Interestingly, the vicarious traumatization scores of the general public were significantly higher than those of the front-line nurses (P < 0.001); however, no statistical difference was observed compared to the scores of non-front-line nurses (P > 0.05). Therefore, increased attention should be paid to the psychological problems of the medical staff, especially non-front-line nurses, and general public under the situation of the spread and control of COVID-19. Early strategies that aim to prevent and treat vicarious traumatization in medical staff and general public are extremely necessary.


Subject(s)
Compassion Fatigue/epidemiology , Coronavirus Infections/epidemiology , Nurses/statistics & numerical data , Pneumonia, Viral/epidemiology , Adult , Betacoronavirus , COVID-19 , China/epidemiology , Compassion Fatigue/psychology , Coronavirus Infections/nursing , Female , Humans , Male , Nurses/psychology , Pandemics , Pneumonia, Viral/nursing , SARS-CoV-2 , Surveys and Questionnaires , Young Adult
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