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1.
Asian journal of psychiatry ; 2023.
Article in English | EuropePMC | ID: covidwho-20234068

ABSTRACT

In this randomized clinical trial, we investigated the efficacy of an online solution focused brief therapy (SFBT) for adolescents' anxiety symptoms during the COVID-19 period. Eligible participants were between the ages of 11 and 18 years, scored a 10 or above on the Generalized Anxiety Disorder-7 (GAD-7). The results found that compared to adolescents who did not receive any treatment, the intervention yielded significant results in alleviating adolescents' anxiety and depressive symptoms while promoting problem oriented coping strategies at immediate post-intervention. The therapeutic benefit has persisted, as shown in our results from the 1-month follow-up.

2.
Asian J Psychiatr ; 86: 103660, 2023 Jun 08.
Article in English | MEDLINE | ID: covidwho-20234067

ABSTRACT

In this randomized clinical trial, we investigated the efficacy of an online solution focused brief therapy (SFBT) for adolescents' anxiety symptoms during the COVID-19 period. Eligible participants were between the ages of 11 and 18 years, scored a 10 or above on the Generalized Anxiety Disorder-7 (GAD-7). The results found that compared to adolescents who did not receive any treatment, the intervention yielded significant results in alleviating adolescents' anxiety and depressive symptoms while promoting problem oriented coping strategies at immediate post-intervention. The therapeutic benefit has persisted, as shown in our results from the 1-month follow-up.

3.
ACS Sens ; 8(5): 2096-2104, 2023 05 26.
Article in English | MEDLINE | ID: covidwho-2327385

ABSTRACT

The large-scale pandemic and fast evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have triggered an urgent need for an efficient and sensitive on-site nucleic acid testing method with single-nucleotide polymorphism (SNP) identification capability. Here, we report a multiplexed electrical detection assay based on a paperclip-shaped nucleic acid probe (PNprobe) functionalized field-effect transistor (FET) biosensor for highly sensitive and specific detection and discrimination of SARS-CoV-2 variants. The three-stem structure of the PNprobe significantly amplifies the thermodynamic stability difference between variant RNAs that differ in a single-nucleotide mutation. With the assistance of combinatorial FET detection channels, the assay realizes simultaneously the detection and identification of key mutations of seven SARS-CoV-2 variants, including nucleotide substitutions and deletions at single-nucleotide resolution within 15 min. For 70 simulated throat swab samples, the multiplexed electrical detection assay shows an identification accuracy of 97.1% for the discrimination of SARS-CoV-2 variants. Our designed multiplexed electrical detection assay with SNP identification capability provides an efficient tool to achieve scalable pandemic screening.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , Polymorphism, Single Nucleotide , SARS-CoV-2/genetics , Nucleic Acid Probes , Nucleotides
4.
Angew Chem Int Ed Engl ; : e202304298, 2023 May 22.
Article in English | MEDLINE | ID: covidwho-2322380

ABSTRACT

Mass pathogen screening is critical to preventing the outbreaks and spread of infectious diseases. The large-scale epidemic of COVID-19 and the rapid mutation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus have put forward new requirements for virus detection and identification techniques. Here, we report a CRISPR-based Amplification-free Viral RNA Electrical Detection platform (CAVRED) for the rapid detection and identification of SARS-CoV-2 variants. A series of CRISPR RNA assays were designed to amplify the CRISPR-Cas system's ability to discriminate between mutant and wild RNA genomes with a single-nucleotide difference. The identified viral RNA information was converted into readable electrical signals through field-effect transistor biosensors for the achievement of highly sensitive detection of single-base mutations. CAVRED can detect the SARS-CoV-2 virus genome as low as 1 cp µL-1 within 20 mins without amplification, and this value is comparable to the detection limit of real-time quantitative polymerase chain reaction. Based on the excellent RNA mutation detection ability, an 8-in-1 CAVRED array was constructed and realized the rapid identification of 40 simulated throat swab samples of SARS-CoV-2 variants with a 95.0 % accuracy. The advantages of accuracy, sensitivity, and fast speed of CAVRED promise its application in rapid and large-scale epidemic screening.

5.
Front Immunol ; 13: 952650, 2022.
Article in English | MEDLINE | ID: covidwho-2326989

ABSTRACT

Given pandemic risks of zoonotic SARS-CoV-2 variants and other SARS-like coronaviruses in the future, it is valuable to perform studies on conserved antigenic sites to design universal SARS-like coronavirus vaccines. By using antibodies obtained from convalescent COVID-19 patients, we succeeded in functional comparison of conserved antigenic sites at multiple aspects with each other, and even with SARS-CoV-2 unique antigenic sites, which promotes the cognition of process of humoral immune response to the conserved antigenic sites. The conserved antigenic sites between SARS-CoV-2 and SARS-CoV can effectively induce affinity maturation of cross-binding antibodies, finally resulting in broadly neutralizing antibodies against multiple variants of concern, which provides an important basis for universal vaccine design, however they are subdominant, putatively due to their lower accessibility relative to SARS-CoV-2 unique antigenic sites. Furthermore, we preliminarily design RBDs to improve the immunogenicity of these conserved antigenic sites. Our study focusing on conserved antigenic sites provides insights for promoting the development of universal SARS-like coronavirus vaccines, thereby enhancing our pandemic preparedness.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Broadly Neutralizing Antibodies , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Spike Glycoprotein, Coronavirus/genetics
6.
Adv Sci (Weinh) ; 10(17): e2207249, 2023 06.
Article in English | MEDLINE | ID: covidwho-2299008

ABSTRACT

Highly pathogenic coronavirus (CoV) infection induces a defective innate antiviral immune response coupled with the dysregulated release of proinflammatory cytokines and finally results in acute respiratory distress syndrome (ARDS). A timely and appropriate triggering of innate antiviral response is crucial to inhibit viral replication and prevent ARDS. However, current medical countermeasures can rarely meet this urgent demand. Here, an antiviral nanobiologic named CoVR-MV is developed, which is polymerized of CoVs receptors based on a biomimetic membrane vesicle system. The designed CoVR-MV interferes with the viral infection by absorbing the viruses with maximized viral spike target interface, and mediates the clearance of the virus through its inherent interaction with macrophages. Furthermore, CoVR-MV coupled with the virus promotes a swift production and signaling of endogenous type I interferon via deregulating 7-dehydrocholesterol reductase (DHCR7) inhibition of interferon regulatory factor 3 (IRF3) activation in macrophages. These sequential processes re-modulate the innate immune responses to the virus, trigger spontaneous innate antiviral defenses, and rescue infected Syrian hamsters from ARDS caused by SARS-CoV-2 and all tested variants.


Subject(s)
COVID-19 , Respiratory Distress Syndrome , Humans , SARS-CoV-2 , Immunity, Innate , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use
7.
International Journal of Human-Computer Interaction ; : 1-21, 2023.
Article in English | Academic Search Complete | ID: covidwho-2288098

ABSTRACT

The development of technology and the recent Covid-19 has moved a substantial part of education into online environments, and video-based learning has become a common format of online learning. An alternative to enhance the co-learning experience in video-based online learning is to make use of immersive virtual reality (VR) technology. The current study focused on how to build a sense of being together in an immersive VR classroom for video-based learning, when individual learners can schedule and pace their learning on their own. Two alternative in-class interaction mechanisms for video-based learning were proposed (i.e., real-time interaction and timeline-anchored interaction). The impact of in-class interaction design was investigated, together with the impact of different styles of visual embodiment of learners (i.e., realistic and cartoon-styled), through a laboratory experiment involving 48 participants, and the influences on learners' immersion in a VR classroom, identification with the avatars, perceived social presence of peer learners, and learning outcomes were analyzed. The results showed that enabling in-class interaction with peer learners in VR classrooms enhances immersion in the learning environment and their identification of peer avatars, as well as helping learners to develop a stronger co-presence and more intimate perception of peers. Whereas real-time interaction improves perceived social presence the most, the reduced learning outcome suggests that it may distract learners from the video. The timeline-anchored interaction, on the other hand, improves social presence at no cost of learning performance. Appearance style, however, has no significant influence on learning experiences and outcomes. [ABSTRACT FROM AUTHOR] Copyright of International Journal of Human-Computer Interaction is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

8.
Cell Host Microbe ; 2022 Oct 18.
Article in English | MEDLINE | ID: covidwho-2237104

ABSTRACT

SARS-CoV-2 spread in humans results in continuous emergence of new variants, highlighting the need for vaccines with broad-spectrum antigenic coverage. Using inter-lineage chimera and mutation-patch strategies, we engineered a recombinant monomeric spike variant (STFK1628x) that contains key regions and residues across multiple SAR-CoV-2 variants. STFK1628x demonstrated high immunogenicity and mutually complementary antigenicity to its prototypic form (STFK). In hamsters, a bivalent vaccine composed of STFK and STFK1628x elicited high titers of broad-spectrum neutralizing antibodies to 19 circulating SARS-CoV-2 variants, including Omicron sublineages BA.1, BA.1.1, BA.2, BA.2.12.1, BA.2.75, and BA.4/5. Furthermore, this vaccine conferred robust protection against intranasal challenges by either SARS-CoV-2 ancestral strain or immune-evasive Beta and Omicron BA.1. Strikingly, vaccination with the bivalent vaccine in hamsters effectively blocked within-cage virus transmission of ancestral SARS-CoV-2, Beta variant, and Omicron BA.1 to unvaccinated sentinels. Thus, our study provided insight and antigen candidates for the development of next-generation COVID-19 vaccines.

9.
J Virol ; 97(2): e0168422, 2023 02 28.
Article in English | MEDLINE | ID: covidwho-2193454

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is becoming a dominant circulator and has several mutations in the spike glycoprotein, which may cause shifts of immunogenicity, so as to result in immune escape and breakthrough infection among the already infected or vaccinated populations. It is unclear whether infection with Omicron could generate adequate cross-variant protection. To investigate this possibility, we used Syrian hamsters as an animal model for infection of SARS-CoV-2. The serum from Omicron BA.1 variant-infected hamsters showed a significantly lower neutralization effect against infection of the same or different SARS-CoV-2 variants than the serum from Beta variant-infected hamsters. Furthermore, the serum from Omicron BA.1 variant-infected hamsters were insufficient to protect against rechallenge of SARS-CoV-2 Prototype, Beta and Delta variants and itself. Importantly, we found that rechallenge with different SARS-CoV-2 lineages elevated cross-variant serum neutralization titers. Overall, our findings indicate a weakened immunogenicity feature of Omicron BA.1 variant that can be overcome by rechallenge of a different SARS-CoV-2 lineages. Our results may lead to a new guideline in generation and use of the vaccinations to combat the pandemic of SARS-CoV-2 Omicron variant and possible new variants. IMPORTANCE The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant causes breakthrough infections among convalescent patients and vaccinated populations. However, Omicron does not generate robust cross-protective responses. Here, we investigate whether heterologous SARS-CoV-2 challenge is able to enhance antibody response in a sensitive animal model, namely, Syrian hamster. Of note, a heterologous challenge of Beta and Omicron BA.1 variant significantly broadens the breadth of SARS-CoV-2 neutralizing responses against the prototype, Beta, Delta, and Omicron BA.1 variants. Our findings confirm that vaccination strategy with heterologous antigens might be a good option to protect against the evolving SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Cricetinae , Antibodies, Neutralizing , Antibodies, Viral , Antigens, Heterophile/immunology , Breakthrough Infections , COVID-19/prevention & control , Mesocricetus , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Immunogenicity, Vaccine
10.
Glob Health Res Policy ; 7(1): 45, 2022 Nov 28.
Article in English | MEDLINE | ID: covidwho-2139788

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has posed particular health risks to United Nations peacekeepers, which require prompt responses and global attention. Since the health protection of United Nations peacekeepers against the COVID-19 pandemic is a typical global health problem, strategies from global health perspectives may help address it. From global health perspectives, and referring to the successful health protection of the Chinese Anti-Ebola medical team in Liberia, a conceptual framework was developed for the health protection of United Nations peacekeepers against the COVID-19 pandemic. Within this framework, the features include multiple cross-borders (cross-border risk factors, impact, and actions); multiple risk factors (Social Determinants of Health), multiple disciplines (public health, medicine, politics, diplomacy, and others), and extensive interdepartmental cooperation. These strategies include multiple phases (before-deployment, during-deployment, and post-deployment), multi-level cooperation networks (the United Nations, host countries, troop-contributing countries, the United Nations peacekeeping team, and United Nations peacekeepers), and concerted efforts from various dimensions (medical, psychological, and social).


Subject(s)
COVID-19 , Pandemics , Humans , Pandemics/prevention & control , COVID-19/epidemiology , COVID-19/prevention & control , Global Health , Public Health , United Nations
11.
Front Immunol ; 13: 1027924, 2022.
Article in English | MEDLINE | ID: covidwho-2119762

ABSTRACT

Objectives: We aimed to evaluate the duration and breadth of antibodies elicited by inactivated COVID-19 vaccinations in healthy blood donors. Methods: We performed serological tests on 1,417 samples from 658 blood donors who received two (n=357), or three (n=301) doses of COVID-19 inactivated vaccine. We also accessed the change in antibody response before and after booster vaccination in 94 participants and their neutralization breadth to the current variants after the booster. Results: Following vaccination, for either the 2- or 3-dose, the neutralizing antibodies (nAbs) peaked with about 97% seropositivity approximately within one month but subsequently decreased over time. Of plasmas collected 6-8 months after the last immunization, the nAb seropositivities were 37% and 85% in populations with 2-dose and 3-dose vaccinations, respectively. The nAbs of plasma samples (collected between 2-6 weeks after the 3rd dose) from triple-vaccinated donors (n=94) showed a geometric mean titer of 145.3 (95% CI: 117.2 to 180.1) against the ancestral B.1, slightly reduced by 1.7-fold against Delta variant, but markedly decreased by 4-6 fold in neutralizing Omicron variants, including the sub-lineages of BA.1 (5.6-fold), BA.1.1 (6.0-fold), BA.2 (4.2-fold), B.2.12.1 (6.2-fold) and BA.4/5 (6.5-fold). Conclusion: These findings suggested that the 3rd dose of inactivated COVID-19 vaccine prolongs the antibody duration in healthy populations, but the elicited-nAbs are less efficient in neutralizing circulating Omicron variants.


Subject(s)
Antibody Formation , COVID-19 , Humans , COVID-19 Vaccines , Blood Donors , COVID-19/prevention & control , SARS-CoV-2 , Antibodies, Neutralizing , Vaccination
12.
iScience ; 25(12): 105475, 2022 Dec 22.
Article in English | MEDLINE | ID: covidwho-2095531

ABSTRACT

Recently, a new variant lineage of SARS-CoV-2, namely Omicron, became the dominant global circulating strain. The multiple antigenic mutations of Omicron largely decrease the efficiency of current vaccines and neutralizing antibodies, which highlights the need for more potent and reachable medical countermeasures. Here, we hypothesize that direct viral clearance by nasal irrigation might be a convenient and alternative option, and perform proof-of-concept experiments in the Syrian hamster model. Interestingly, Omicron shows a different dynamic in the changes of viral RNA, viral titers, and proinflammatory cytokines in nasal rinsing samples when compared with the prototype. Meanwhile, the levels of viral load and proinflammatory cytokines in nasal rinsing samples can indicate the severity of lung injury. Of note, daily nasal irrigation efficiently attenuates inflammation and lung injury in Omicron-infected hamsters by decreasing the viral loads in the respiratory tract organs. Moreover, daily nasal irrigation effectively suppresses viral transmission by close contact.

13.
Cell Mol Immunol ; 19(12): 1392-1399, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2077039

ABSTRACT

The new predominant circulating SARS-CoV-2 variant, Omicron, can robustly escape current vaccines and neutralizing antibodies. Although Omicron has been reported to have milder replication and disease manifestations than some earlier variants, its pathogenicity in different age groups has not been well elucidated. Here, we report that the SARS-CoV-2 Omicron BA.1 sublineage causes elevated infection and lung pathogenesis in juvenile and aged hamsters, with more body weight loss, respiratory tract viral burden, and lung injury in these hamsters than in adult hamsters. Juvenile hamsters show a reduced interferon response against Omicron BA.1 infection, whereas aged hamsters show excessive proinflammatory cytokine expression, delayed viral clearance, and aggravated lung injury. Early inhaled IFN-α2b treatment suppresses Omicron BA.1 infection and lung pathogenesis in juvenile and adult hamsters. Overall, the data suggest that the diverse patterns of the innate immune response affect the disease outcomes of Omicron BA.1 infection in different age groups.


Subject(s)
COVID-19 Drug Treatment , COVID-19 , Interferon-alpha , Lung Injury , Animals , Cricetinae , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral , Antiviral Agents , COVID-19/pathology , Interferon-alpha/therapeutic use , Lung Injury/virology , Mesocricetus , SARS-CoV-2
14.
Frontiers in microbiology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-2046996

ABSTRACT

Background The COVID-19 pandemic has killed over 6 million people worldwide. Despite the accumulation of knowledge about the causative pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the pathogenesis of this disease, cures remain to be discovered. We searched for certain peptides that might interfere with spike protein (S protein)-angiotensin-converting enzyme 2 (ACE2) interactions. Methods Phage display (PhD)-12 peptide library was screened against recombinant spike trimer (S-trimer) or receptor-binding domain (S-RBD) proteins. The resulting enriched peptide sequences were obtained, and their potential binding sites on S-trimer and S-RBD 3D structure models were searched. Synthetic peptides corresponding to these and other reference sequences were tested for their efficacy in blocking the binding of S-trimer protein onto recombinant ACE2 proteins or ACE2-overexpressing cells. Results After three rounds of phage selections, two peptide sequences (C2, DHAQRYGAGHSG;C6, HWKAVNWLKPWT) were enriched by S-RBD, but only C2 was present in S-trimer selected phages. When the 3D structures of static monomeric S-RBD (6M17) and S-trimer (6ZGE, 6ZGG, 7CAI, and 7CAK, each with different status of S-RBDs in the three monomer S proteins) were scanned for potential binding sites of C2 and C6 peptides, C6 opt to bind the saddle of S-RBD in both 6M17 and erected S-RBD in S-trimers, but C2 failed to cluster there in the S-trimers. In the competitive S-trimer-ACE2-binding experiments, synthetic C2 and C6 peptides inhibited S-trimer binding onto 293T-ACE2hR cells at high concentrations (50 μM) but not at lower concentrations (10 μM and below), neither for the settings of S-trimer binding onto recombinant ACE2 proteins. Conclusion Using PhD methodology, two peptides were generated bearing potentials to interfere with S protein-ACE2 interaction, which might be further exploited to produce peptidomimetics that block the attachment of SARS-CoV-2 virus onto host cells, hence diminishing the pathogenesis of COVID-19.

15.
Frontiers in immunology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-2046995

ABSTRACT

Given pandemic risks of zoonotic SARS-CoV-2 variants and other SARS-like coronaviruses in the future, it is valuable to perform studies on conserved antigenic sites to design universal SARS-like coronavirus vaccines. By using antibodies obtained from convalescent COVID-19 patients, we succeeded in functional comparison of conserved antigenic sites at multiple aspects with each other, and even with SARS-CoV-2 unique antigenic sites, which promotes the cognition of process of humoral immune response to the conserved antigenic sites. The conserved antigenic sites between SARS-CoV-2 and SARS-CoV can effectively induce affinity maturation of cross-binding antibodies, finally resulting in broadly neutralizing antibodies against multiple variants of concern, which provides an important basis for universal vaccine design, however they are subdominant, putatively due to their lower accessibility relative to SARS-CoV-2 unique antigenic sites. Furthermore, we preliminarily design RBDs to improve the immunogenicity of these conserved antigenic sites. Our study focusing on conserved antigenic sites provides insights for promoting the development of universal SARS-like coronavirus vaccines, thereby enhancing our pandemic preparedness.

16.
Vaccine ; 40(47): 6839-6848, 2022 Nov 08.
Article in English | MEDLINE | ID: covidwho-2042193

ABSTRACT

The ongoing coronavirus disease-19 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has drastically changed our way of life and continues to have an unmitigated socioeconomic impact across the globe. Research into potential vaccine design and production is focused on the spike (S) protein of the virus, which is critical for virus entry into host cells. Yet, whether the degree of glycosylation in the S protein is associated with vaccine efficacy remains unclear. Here, we first optimized the expression of the S protein in mammalian cells. While we found no significant discrepancy in purity, homogeneity, or receptor binding ability among S proteins derived from 293F cells (referred to as 293F S-2P), 293S GnTI- cells (defective in N-acetylglucosaminyl transferase I enzyme; 293S S-2P), or TN-5B1-4 insect cells (Bac S-2P), there was significant variation in the glycosylation patterns and thermal stability of the proteins. Compared with the partially glycosylated 293S S-2P or Bac S-2P, the fully glycosylated 293F S-2P exhibited higher binding reactivity to convalescent sera. In addition, 293F S-2P induced higher IgG and neutralizing antibody titres than 293S or Bac S-2P in mice. Furthermore, a prime-boost-boost regimen, using a combined immunization of S-2P proteins with various degrees of glycosylation, elicited a more robust neutralizing antibody response than a single S-2P alone. Collectively, this study provides insight into ways to design a more effective SARS-CoV-2 immunogen.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Humans , Mice , Animals , SARS-CoV-2 , Glycosylation , COVID-19/prevention & control , Antibodies, Neutralizing , Antibodies, Viral , Mammals/metabolism , COVID-19 Serotherapy
17.
Proc Natl Acad Sci U S A ; 119(34): e2204256119, 2022 08 23.
Article in English | MEDLINE | ID: covidwho-1991767

ABSTRACT

Antibody therapeutics for the treatment of COVID-19 have been highly successful. However, the recent emergence of the Omicron variant has posed a challenge, as it evades detection by most existing SARS-CoV-2 neutralizing antibodies (nAbs). Here, we successfully generated a panel of SARS-CoV-2/SARS-CoV cross-neutralizing antibodies by sequential immunization of the two pseudoviruses. Of the potential candidates, we found that nAbs X01, X10, and X17 offer broad neutralizing potential against most variants of concern, with X17 further identified as a Class 5 nAb with undiminished neutralization against the Omicron variant. Cryo-electron microscopy structures of the three antibodies together in complex with each of the spike proteins of the prototypical SARS-CoV, SARS-CoV-2, and Delta and Omicron variants of SARS-CoV-2 defined three nonoverlapping conserved epitopes on the receptor-binding domain. The triple-antibody mixture exhibited enhanced resistance to viral evasion and effective protection against infection of the Beta variant in hamsters. Our findings will aid the development of antibody therapeutics and broad vaccines against SARS-CoV-2 and its emerging variants.


Subject(s)
Antibodies, Neutralizing , Antibodies, Viral , Epitopes , SARS-CoV-2 , Severe acute respiratory syndrome-related coronavirus , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , Conserved Sequence , Cricetinae , Cryoelectron Microscopy , Epitopes/immunology , Humans , Mice , Neutralization Tests , Severe acute respiratory syndrome-related coronavirus/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics
19.
J Virol Methods ; 307: 114564, 2022 09.
Article in English | MEDLINE | ID: covidwho-1878302

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 infections has led to excess deaths worldwide. Neutralizing antibodies (nAbs) against viral spike protein acquired from natural infections or vaccinations contribute to protection against new- and re-infections. Besides neutralization, antibody-mediated cellular cytotoxicity (ADCC) and phagocytosis (ADCP) are also important for viral clearance. However, due to the lack of convenient methods, the ADCC and ADCP responses elicited by viral infections or vaccinations remain to be explored. Here, we developed cell-based assays using target cells stably expressing SARS-CoV-2 spikes and Jurkat-NFAT-CD16a/CD32a effector cells for ADCC/ADCP measurements of monoclonal antibodies and human convalescent COVID-19 plasmas (HCPs). In control samples (n = 190), the specificity was 99.5% (95%CI: 98.4-100%) and 97.4% (95%CI: 95.1-99.6%) for the ADCC and ADCP assays, respectively. Among 87 COVID-19 HCPs, 83 (sensitivity: 95.4%, 95%CI: 91.0-99.8%) and 81 (sensitivity: 93.1%, 95%CI: 87.8-98.4%) showed detectable ADCC (titer range: 7.4-1721.6) and ADCP activities (titer range: 4-523.2). Notably, both ADCC and ADCP antibody titers positively correlated with the nAb titers in HCPs. In summary, we developed new tools for quantitative ADCC and ADCP analysis against SARS-CoV-2, which may facilitate further evaluations of Fc-mediated effector functions in preventing and treating against SARS-CoV-2.


Subject(s)
Antibody-Dependent Cell Cytotoxicity , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 , Humans , Immunoassay/methods , Pandemics , Phagocytosis , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism
20.
Sci Bull (Beijing) ; 67(13): 1372-1387, 2022 Jul 15.
Article in English | MEDLINE | ID: covidwho-1867754

ABSTRACT

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 d after single-dose vaccination or 9 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants, especially for the latest Omicron variant. In addition, this vaccine also provides cross-protection against H1N1 and H5N1 influenza viruses. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to the fight against the ongoing coronavirus disease 2019 pandemic and influenza infection, compensating limitations of current intramuscular vaccines.

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