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2.
J Mol Med (Berl) ; 100(4): 613-627, 2022 04.
Article in English | MEDLINE | ID: covidwho-1729276

ABSTRACT

SARS-CoV-2 has evolved to enter the host via the ACE2 receptor which is part of the kinin-kallikrein pathway. This complex pathway is only poorly understood in context of immune regulation but critical to control infection. This study examines SARS-CoV-2-infection and epithelial mechanisms of the kinin-kallikrein-system at the kinin B2 receptor level in SARS-CoV-2-infection that is of direct translational relevance. From acute SARS-CoV-2-positive study participants and -negative controls, transcriptomes of nasal curettages were analyzed. Primary airway epithelial cells (NHBEs) were infected with SARS-CoV-2 and treated with the approved B2R-antagonist icatibant. SARS-CoV-2 RNA RT-qPCR, cytotoxicity assays, plaque assays, and transcriptome analyses were performed. The treatment effect was further studied in a murine airway inflammation model in vivo. Here, we report a broad and strong upregulation of kallikreins and the kinin B2 receptor (B2R) in the nasal mucosa of acutely symptomatic SARS-CoV-2-positive study participants. A B2R-antagonist impeded SARS-CoV-2 replication and spread in NHBEs, as determined in plaque assays on Vero-E6 cells. B2R-antagonism reduced the expression of SARS-CoV-2 entry receptor ACE2, G protein-coupled receptor signaling, and ion transport in vitro and in a murine airway inflammation in vivo model. In summary, this study provides evidence that treatment with B2R-antagonists protects airway epithelial cells from SARS-CoV-2 by inhibiting its replication and spread, through the reduction of ACE2 levels and the interference with several cellular signaling processes. Future clinical studies need to shed light on the airway protection potential of approved B2R-antagonists, like icatibant, in the treatment of early-stage COVID-19. KEY MESSAGES: Induction of kinin B2 receptor in the nose of SARS-CoV-2-positive patients. Treatment with B2R-antagonist protects airway epithelial cells from SARS-CoV-2. B2R-antagonist reduces ACE2 levels in vivo and ex vivo. Protection by B2R-antagonist is mediated by inhibiting viral replication and spread.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , COVID-19/drug therapy , Epithelium , Humans , Mice , RNA, Viral , Receptor, Bradykinin B2/genetics , Receptor, Bradykinin B2/metabolism
3.
Emerg Infect Dis ; 28(3): 572-581, 2022 03.
Article in English | MEDLINE | ID: covidwho-1706937

ABSTRACT

Hospital staff are at high risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease (COVID-19) pandemic. This cross-sectional study aimed to determine the prevalence of SARS-CoV-2 infection in hospital staff at the University Hospital rechts der Isar in Munich, Germany, and identify modulating factors. Overall seroprevalence of SARS-CoV-2-IgG in 4,554 participants was 2.4%. Staff engaged in direct patient care, including those working in COVID-19 units, had a similar probability of being seropositive as non-patient-facing staff. Increased probability of infection was observed in staff reporting interactions with SARS-CoV-2‒infected coworkers or private contacts or exposure to COVID-19 patients without appropriate personal protective equipment. Analysis of spatiotemporal trajectories identified that distinct hotspots for SARS-CoV-2‒positive staff and patients only partially overlap. Patient-facing work in a healthcare facility during the SARS-CoV-2 pandemic might be safe as long as adequate personal protective equipment is used and infection prevention practices are followed inside and outside the hospital.


Subject(s)
COVID-19 , SARS-CoV-2 , Cross-Sectional Studies , Germany/epidemiology , Health Personnel , Hospitals, University , Humans , Immunoglobulin G , Infection Control , Personnel, Hospital , Prevalence , Seroepidemiologic Studies
4.
Gut Microbes ; 14(1): 2031840, 2022.
Article in English | MEDLINE | ID: covidwho-1692369

ABSTRACT

There is a growing debate about the involvement of the gut microbiome in COVID-19, although it is not conclusively understood whether the microbiome has an impact on COVID-19, or vice versa, especially as analysis of amplicon data in hospitalized patients requires sophisticated cohort recruitment and integration of clinical parameters. Here, we analyzed fecal and saliva samples from SARS-CoV-2 infected and post COVID-19 patients and controls considering multiple influencing factors during hospitalization. 16S rRNA gene sequencing was performed on fecal and saliva samples from 108 COVID-19 and 22 post COVID-19 patients, 20 pneumonia controls and 26 asymptomatic controls. Patients were recruited over the first and second corona wave in Germany and detailed clinical parameters were considered. Serial samples per individual allowed intra-individual analysis. We found the gut and oral microbiota to be altered depending on number and type of COVID-19-associated complications and disease severity. The occurrence of individual complications was correlated with low-risk (e.g., Faecalibacterium prausznitzii) and high-risk bacteria (e.g., Parabacteroides ssp.). We demonstrated that a stable gut bacterial composition was associated with a favorable disease progression. Based on gut microbial profiles, we identified a model to estimate mortality in COVID-19. Gut microbiota are associated with the occurrence of complications in COVID-19 and may thereby influencing disease severity. A stable gut microbial composition may contribute to a favorable disease progression and using bacterial signatures to estimate mortality could contribute to diagnostic approaches. Importantly, we highlight challenges in the analysis of microbial data in the context of hospitalization.


Subject(s)
COVID-19/microbiology , Dysbiosis/microbiology , Gastrointestinal Microbiome , Aged , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , COVID-19/complications , COVID-19/mortality , Disease Progression , Dysbiosis/etiology , Feces/microbiology , Female , Humans , Male , Microbiota , Middle Aged , SARS-CoV-2 , Saliva/microbiology , Severity of Illness Index
5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-322329

ABSTRACT

SARS-CoV-2 enters host cells after binding through its spike glycoprotein to the angiotensin-converting enzyme 2 (ACE2) receptor. Soluble ACE2 ectodomains bind and neutralize the virus, yet their short in vivo half-live limits their therapeutic use. This limitation can be overcome by fusing the fragment crystallizable (Fc) part of human immunoglobulin G (IgG) to the ACE2 ectodomain, but this bears the risk of unwanted Fc-receptor activation and antibody-dependent disease enhancement. Here, we describe optimized ACE2-IgG4-Fc fusion constructs that avoid Fc-receptor activation, preserve the desired ACE-2 enzymatic activity and show promising pharmaceutical properties. The engineered ACE2-IgG4-Fc fusion proteins neutralize the original SARS-CoV, pandemic SARS-CoV-2 as well as the rapidly spreading SARS-CoV-2 variants-of-concern, B.1.17 and B.1.351. Importantly, these variants-of-concern are inhibited at picomolar concentrations proving that ACE-2-IgG4 maintains – in contrast to therapeutic antibodies - its full antiviral potential. Thus, ACE2-IgG4-Fc fusion proteins are promising candidate anti-antivirals to combat the current and future pandemics.

6.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-320926

ABSTRACT

Background: In the absence of PCR detection of SARS-CoV-2 RNA, accurate diagnosis of COVID-19 is challenging. Low-dose computed tomography (CT) detects pulmonary infiltrates with high sensitivity, but findings may be non-specific. This study assesses the diagnostic value of SARS-CoV-2 serology for patients with distinct CT features but negative PCR. Methods: : IgM/IgG chemiluminescent immunoassay was performed for 107 patients with confirmed (group A: PCR+;CT±) and 46 patients with suspected (group B: repetitive PCR-;CT+) COVID-19, admitted to a German university hospital during the pandemic’s first wave. A standardized, in-house CT classification of radiological signs of a viral pneumonia was used to assess the probability of COVID-19. Results: : Seroconversion rates (SR) determined on day 5, 10, 15, 20 and 25 after symptom onset (SO) were 8%, 25%, 65%, 76% and 91% for group A, and 0%, 10%, 19%, 37% and 46% for group B, respectively;(p<0.01). Compared to hospitalized patients with a non-complicated course, seroconversion tended to occur at lower frequency and delayed in patients on intensive care units. SR of patients with CT findings classified as high certainty for COVID-19 were 8%, 22%, 68%, 79% and 93% in group A, compared with 0%, 15%, 28%, 50% and 50% in group B (p<0.01). SARS-CoV-2 serology established a definite diagnosis in 12/46 group B patients. In 88% (8/9) of patients with negative serology >14 days after symptom onset (group B), clinico-radiological consensus reassessment revealed probable diagnoses other than COVID-19. Sensitivity of SARS-CoV-2 serology was superior to PCR >17d after symptom onset. Conclusions: : Approximately one-third of patients with distinct COVID-19 CT findings are tested negative for SARS-CoV-2 RNA by PCR rendering correct diagnosis difficult. Implementation of SARS-CoV-2 serology testing alongside current CT/PCR-based diagnostic algorithms improves discrimination between COVID-19-related and non-related pulmonary infiltrates in PCR negative patients. However, sensitivity of SARS-CoV-2 serology strongly depends on the time of testing and becomes superior to PCR after the 2 nd week following symptom onset.

7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-314315

ABSTRACT

Infection with the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is controlled by the host´s immune response1-4, but longitudinal follow-up studies of virus-specific immunity to evaluate protection from re-infection are lacking. Here, we report the results from a prospective study that started during the first wave of the COVID-19 pandemic in spring 2020, where we identified 91 convalescents from mild SARS-CoV-2 infection among 4554 health care workers. We followed the dynamics and magnitude of spike-specific immunity in convalescents during the spontaneous course over ≥ 9 months, after SARS-CoV-2 re-exposure and after BNT162b2 mRNA vaccination. Virus-neutralizing antibodies and spike-specific T cell responses with predominance of IL-2-secreting polyfunctional CD4 T cells continuously declined over 9 months, but remained detectable at low levels. After a single vaccination, convalescents simultaneously mounted strong antibody and T cell responses against the SARS-CoV-2 spike proteins. In naïve individuals, a prime vaccination induced preferentially IL-2-secreting CD4 T cells that preceded production of spike-specific virus-neutralizing antibodies after boost vaccination. Response to vaccination, however, was not homogenous. Compared to four individuals among 455 naïve vaccinees (0.9%), we identified 5/82 (6.1%) convalescents with a delayed response to vaccination. These convalescents had originally developed dysfunctional spike-specific immune responses after SARS-CoV-2 infection, and required prime and boost vaccination to develop strong spike-specific immunity. Importantly, during the second wave of the COVID-19 pandemic in fall/winter of 2021 and prior to vaccination we detected a surge of virus-neutralizing antibodies consistent with re-exposure to SARS-CoV-2 in 6 out of 82 convalescents. The selective increase in virus-neutralizing antibodies occurred without systemic re-activation of spike-specific T cell immunity, whereas a single BNT162b2 mRNA vaccination sufficed to induce strong spike-specific antibody and systemic T cell responses in the same individuals. These results support the notion that BNT162b2 mRNA vaccination synchronizes spike-specific immunity in all convalescents of mild SARS-CoV-2 infection and may provide additional protection from re-infection by inducing more rigorous stimulation of spike-specific T cell immunity than re-exposure with SARS-CoV-2.

9.
Anal Chem ; 94(6): 2855-2864, 2022 02 15.
Article in English | MEDLINE | ID: covidwho-1671472

ABSTRACT

Lateral-flow immunoassays and laboratory diagnostic tests like enzyme-linked immunosorbent assays (ELISAs) are powerful diagnostic tools to help fight the COVID-19 pandemic using them as antigen or antibody tests. However, the need emerges for alternative bioanalytical systems that combine their favorable features─simple, rapid, and cost-efficient point-of-care (POC) analysis of lateral-flow immunoassays and higher reliability of laboratory tests─while eliminating their disadvantages (limited sensitivity and specificity of lateral-flow assays and prolonged time and work expenditure of laboratory analysis). An additional need met by only a few tests is multiplexing, allowing for the analysis of several immunorecognition patterns at the same time. We herein present a strategy to combine all desirable attributes of the different test types by means of a flow-based chemiluminescence microarray immunoassay. Laminated polycarbonate microarray chips were developed for easy production and subsequent application in the fully automated microarray analysis platform MCR-R, where a novel flow cell design minimizes the sample volume to 40 µL. This system was capable of detecting IgG antibodies to SARS-CoV-2 with 100% sensitivity and specificity using recombinant antigens for the SARS-CoV-2 spike S1 protein, nucleocapsid protein, and receptor binding domain. The analysis was accomplished within under 4 min from serum, plasma, and whole blood, making it also useful in POC settings. Additionally, we showed the possibility of serosurveillance after infection or vaccination to monitor formerly unnoticed breakthrough infections in the population as well as to detect the need for booster vaccination after the natural decline of the antibody titer below detectable levels. This will help in answering pressing questions on the importance of the antibody response to SARS-CoV-2 that so far remain open. Additionally, even the sequential detection of IgM and IgG antibodies was possible, allowing for statements on the time response of an infection. While our serodiagnostic application focuses on SARS-CoV-2, the same approach is easily adjusted to other diseases, making it a powerful tool for future serological testing.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Immunoassay , Immunoglobulin M , Luminescence , Microarray Analysis , Pandemics , Reproducibility of Results , Sensitivity and Specificity
10.
Nat Med ; 28(3): 496-503, 2022 03.
Article in English | MEDLINE | ID: covidwho-1655606

ABSTRACT

Infection-neutralizing antibody responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or coronavirus disease 2019 vaccination are an essential component of antiviral immunity. Antibody-mediated protection is challenged by the emergence of SARS-CoV-2 variants of concern (VoCs) with immune escape properties, such as omicron (B.1.1.529), which is rapidly spreading worldwide. Here we report neutralizing antibody dynamics in a longitudinal cohort of coronavirus disease 2019 convalescent and infection-naive individuals vaccinated with mRNA BNT162b2 by quantifying SARS-CoV-2 spike protein antibodies and determining their avidity and neutralization capacity in serum. Using live-virus neutralization assays, we show that a superior infection-neutralizing capacity against all VoCs, including omicron, developed after either two vaccinations in convalescents or a third vaccination or breakthrough infection of twice-vaccinated, naive individuals. These three consecutive spike antigen exposures resulted in an increasing neutralization capacity per anti-spike antibody unit and were paralleled by stepwise increases in antibody avidity. We conclude that an infection-plus-vaccination-induced hybrid immunity or a triple immunization can induce high-quality antibodies with superior neutralization capacity against VoCs, including omicron.


Subject(s)
COVID-19 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/prevention & control , Humans , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination
11.
Comput Struct Biotechnol J ; 20: 799-811, 2022.
Article in English | MEDLINE | ID: covidwho-1654283

ABSTRACT

Drug-repurposing has been instrumental to identify drugs preventing SARS-CoV-2 replication or attenuating the disease course of COVID-19. Here, we identify through structure-based drug-repurposing a dual-purpose inhibitor of SARS-CoV-2 infection and of IL-6 production by immune cells. We created a computational structure model of the receptor binding domain (RBD) of the SARS-CoV-2 spike 1 protein, and used this model for insilico screening against a library of 6171 molecularly defined binding-sites from drug molecules. Molecular dynamics simulation of candidate molecules with high RBD binding-scores in docking analysis predicted montelukast, an antagonist of the cysteinyl-leukotriene-receptor, to disturb the RBD structure, and infection experiments demonstrated inhibition of SARS-CoV-2 infection, although montelukast binding was outside the ACE2-binding site. Molecular dynamics simulation of SARS-CoV-2 variant RBDs correctly predicted interference of montelukast with infection by the beta but not the more infectious alpha variant. With distinct binding sites for RBD and the leukotriene receptor, montelukast also prevented SARS-CoV-2-induced IL-6 release from immune cells. The inhibition of SARS-CoV-2 infection through a molecule binding distal to the ACE-binding site of the RBD points towards an allosteric mechanism that is not conserved in the more infectious alpha and delta SARS-CoV-2 variants.

12.
Nat Commun ; 13(1): 153, 2022 01 10.
Article in English | MEDLINE | ID: covidwho-1616980

ABSTRACT

Anti-viral immunity continuously declines over time after SARS-CoV-2 infection. Here, we characterize the dynamics of anti-viral immunity during long-term follow-up and after BNT162b2 mRNA-vaccination in convalescents after asymptomatic or mild SARS-CoV-2 infection. Virus-specific and virus-neutralizing antibody titers rapidly declined in convalescents over 9 months after infection, whereas virus-specific cytokine-producing polyfunctional T cells persisted, among which IL-2-producing T cells correlated with virus-neutralizing antibody titers. Among convalescents, 5% of individuals failed to mount long-lasting immunity after infection and showed a delayed response to vaccination compared to 1% of naïve vaccinees, but successfully responded to prime/boost vaccination. During the follow-up period, 8% of convalescents showed a selective increase in virus-neutralizing antibody titers without accompanying increased frequencies of circulating SARS-CoV-2-specific T cells. The same convalescents, however, responded to vaccination with simultaneous increase in antibody and T cell immunity revealing the strength of mRNA-vaccination to increase virus-specific immunity in convalescents.


Subject(s)
/immunology , COVID-19/immunology , Convalescence , Nucleocapsid/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/virology , Cytokines/immunology , Cytokines/metabolism , Flow Cytometry/methods , Follow-Up Studies , Humans , Immunoglobulin G/immunology , Interleukin-2/immunology , Interleukin-2/metabolism , Kinetics , SARS-CoV-2/physiology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , T-Lymphocytes/virology , Time Factors , Vaccination/methods
13.
Internist (Berl) ; 63(1): 118-128, 2022 Jan.
Article in German | MEDLINE | ID: covidwho-1603180

ABSTRACT

Antiviral drugs inhibit viral replication by interaction with specific elements of the viral replication cycle. Directly acting antiviral agents have revolutionized the therapeutic options for chronic infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). Pharmacological developments constantly improve therapeutic and prophylactic options for diseases caused by herpes viruses, which is of particular relevance for immunocompromised patients. While infections with persistent viruses, such as HIV, HBV or herpes viruses principally so far cannot be cured, complete elimination of viruses that cause acute infections is possible; however, acute infections, such as influenza or coronavirus disease 2019 (COVID-19) offer only a small therapeutic window for antiviral strategies due to their pathophysiological dynamics. The optimal time point for antiviral agents is immediately after exposure to the virus, which frequently limits its application in practice. An effective pre-exposure or postexposure prophylaxis has been established for infections with HIV and influenza A/B and also gains relevance for infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).


Subject(s)
COVID-19 , Antiviral Agents/therapeutic use , Hepacivirus , Humans , SARS-CoV-2
14.
Cell Rep ; 38(2): 110214, 2022 01 11.
Article in English | MEDLINE | ID: covidwho-1588141

ABSTRACT

T cell immunity is crucial for control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and has been studied widely on a quantitative level. However, the quality of responses, in particular of CD8+ T cells, has only been investigated marginally so far. Here, we isolate T cell receptor (TCR) repertoires specific for immunodominant SARS-CoV-2 epitopes restricted to common human Leukocyte antigen (HLA) class I molecules in convalescent individuals. SARS-CoV-2-specific CD8+ T cells are detected up to 12 months after infection. TCR repertoires are diverse, with heterogeneous functional avidity and cytotoxicity toward virus-infected cells, as demonstrated for TCR-engineered T cells. High TCR functionality correlates with gene signatures that, remarkably, could be retrieved for each epitope:HLA combination analyzed. Overall, our data demonstrate that polyclonal and highly functional CD8+ TCRs-classic features of protective immunity-are recruited upon mild SARS-CoV-2 infection, providing tools to assess the quality of and potentially restore functional CD8+ T cell immunity.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Receptors, Antigen, T-Cell/immunology , SARS-CoV-2/immunology , Adult , Cells, Cultured , Cross Reactions/immunology , Epitopes, T-Lymphocyte/immunology , Female , Humans , Immunodominant Epitopes/immunology , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/virology , Male , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes, Cytotoxic/immunology
15.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-295758

ABSTRACT

In this position paper, a large group of interdisciplinary experts outlines response strategies against the spread of SARS-CoV-2 in the winter of 2021/2022 in Germany. We review the current state of the COVID-19 pandemic, from incidence and vaccination efficacy to hospital capacity. Building on this situation assessment, we illustrate various possible scenarios for the winter, and detail the mechanisms and effectiveness of the non-pharmaceutical interventions, vaccination, and booster. With this assessment, we want to provide orientation for decision makers about the progress and mitigation of COVID-19.

16.
J Voice ; 2021 Nov 27.
Article in English | MEDLINE | ID: covidwho-1536942

ABSTRACT

Due to the drastically rising coronavirus disease (COVID-19) incidence since March 2020, social life was shut down across the globe, and most opera houses were closed. As a result, there are limited data on SARS-CoV-2 infections among artists. The Bavarian State Opera has been reopened in September 2020. This study aimed to identify the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among employees in the Bavarian State Opera. In addition, the various hygiene strategies for the work groups within the institution are described. During the study period from September 1, 2020 to July 31, 2021, 10,061 nasopharyngeal swabs were obtained from 1,460 artistic staff members in a rolling system. During the entire study period, 61 individuals tested positive for SARS-CoV-2. None of the patients had a severe disease course. Compared to the seven-day-incidence per 100,000 German inhabitants, the estimated corresponding incidence among employees was lower at 37 weeks and higher or equal at 9 weeks. Among the infected individuals, 58.3% were symptomatic, 23.3% were presymptomatic, and 18.3% were asymptomatic. Forty-five percent of employees reported that they had been infected in their private environment, 41.7% suspected that their colleagues were the main contact, and 13.3% were unsure about the origin of their infection. Twenty-four diseased employees were ballet dancers, eight from the orchestra, seven from the administration, seven from the choir singers, six from the costume department, 10 from technical support, and one guest solo singer. In the 2020/2021 theater season, increased SARS-CoV-2 infections and large disease outbreaks were avoided at the Bavarian State Opera. Hygiene strategies, that existed since the beginning, was specifically designed for various work areas in the opera. Regular, mandatory PCR testing and follow-up of positive cases with the issuance of quarantine were performed. Using this disease management approach, artistic work at and reopening of the Bavarian State Opera was feasible with a well-controlled risk.

17.
JMIR Form Res ; 6(1): e32564, 2022 Jan 04.
Article in English | MEDLINE | ID: covidwho-1528774

ABSTRACT

BACKGROUND: Large-scale, polymerase chain reaction (PCR)-based SARS-CoV-2 testing is expensive, resource intensive, and time consuming. A self-collection approach is a probable alternative; however, its feasibility, cost, and ability to prevent infections need to be evaluated. OBJECTIVE: This study aims to compare an innovative self-collection approach with a regular SARS-CoV-2 testing strategy in a large European industrial manufacturing site. METHODS: The feasibility of a telemedicine-guided PCR-based self-collection approach was assessed for 150 employees (intervention group) and compared with a regular SARS-CoV-2 testing approach used for 143 employees (control group). Acceptance, ergonomics, and efficacy were evaluated using a software application. A simulation model was implemented to evaluate the effectiveness. An interactive R shiny app was created to enable customized simulations. RESULTS: The test results were successfully communicated to and interpreted without uncertainty by 76% (114/150) and 76.9% (110/143) of the participants in the intervention and control groups, respectively (P=.96). The ratings for acceptability, ergonomics, and efficacy among intervention group participants were noninferior when compared to those among control group participants (acceptability: 71.6% vs 37.6%; ergonomics: 88.1% vs 74.5%; efficacy: 86.4% vs 77.5%). The self-collection approach was found to be less time consuming (23 min vs 38 min; P<.001). The simulation model indicated that both testing approaches reduce the risk of infection, and the self-collection approach tends to be slightly less effective owing to its lower sensitivity. CONCLUSIONS: The self-collection approach for SARS-CoV-2 diagnosis was found to be technically feasible and well rated in terms of acceptance, ergonomics, and efficacy. The simulation model facilitates the evaluation of test effectiveness; nonetheless, considering context specificity, appropriate adaptation by companies is required.

18.
Nat Commun ; 12(1): 6737, 2021 11 18.
Article in English | MEDLINE | ID: covidwho-1526077

ABSTRACT

Antibodies bind antigens via flexible loops called complementarity-determining regions (CDRs). These are usually 6-20 residues long. However, some bovine antibodies have ultra-long CDRs comprising more than 50 residues organized in a stalk and a disulfide-rich knob. The design features of this structural unit and its influence on antibody stability remained enigmatic. Here, we show that the stalk length is critical for the folding and stability of antibodies with an ultra-long CDR and that the disulfide bonds in the knob do not contribute to stability; they are important for organizing the antigen-binding knob structure. The bovine ultra-long CDR can be integrated into human antibody scaffolds. Furthermore, mini-domains from de novo design can be reformatted as ultra-long CDRs to create unique antibody-based proteins neutralizing SARS-CoV-2 and the Alpha variant of concern with high efficiency. Our findings reveal basic design principles of antibody structure and open new avenues for protein engineering.


Subject(s)
Complementarity Determining Regions/genetics , SARS-CoV-2/genetics , Animals , Antibodies, Viral/genetics , Antibodies, Viral/immunology , COVID-19/genetics , Cattle
19.
Antiviral Res ; 196: 105197, 2021 12.
Article in English | MEDLINE | ID: covidwho-1509565

ABSTRACT

SARS-CoV-2 enters host cells after binding through its spike glycoprotein to the angiotensin-converting enzyme 2 (ACE2) receptor. Soluble ACE2 ectodomains bind and neutralize the virus, yet their short in vivo half-live limits their therapeutic use. This limitation can be overcome by fusing the fragment crystallizable (Fc) part of human immunoglobulin G (IgG) to the ACE2 ectodomain, but this bears the risk of Fc-receptor activation and antibody-dependent cellular cytotoxicity. Here, we describe optimized ACE2-IgG4-Fc fusion constructs that avoid Fc-receptor activation, preserve the desired ACE2 enzymatic activity and show promising pharmaceutical properties. The engineered ACE2-IgG4-Fc fusion proteins neutralize the original SARS-CoV, pandemic SARS-CoV-2 as well as the rapidly spreading SARS-CoV-2 alpha, beta and delta variants of concern. Importantly, these variants of concern are inhibited at picomolar concentrations proving that ACE2-IgG4 maintains - in contrast to therapeutic antibodies - its full antiviral potential. Thus, ACE2-IgG4-Fc fusion proteins are promising candidate anti-antivirals to combat the current and future pandemics.


Subject(s)
Angiotensin-Converting Enzyme 2 , Antiviral Agents/chemical synthesis , COVID-19/drug therapy , Immunoglobulin G , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/therapeutic use , Antiviral Agents/therapeutic use , Humans , Protein Binding , SARS-CoV-2/drug effects
20.
J Clin Med ; 10(22)2021 Nov 12.
Article in English | MEDLINE | ID: covidwho-1512415

ABSTRACT

Deficiencies in smell and taste are common symptoms of COVID-19. Quantitative losses are well surveyed. This study focuses on qualitative changes such as phantosmia (hallucination of smell), parosmia (alteration of smell), and dysgeusia (alteration of taste) and possible connections with the adaptive immune system. Subjective experience of deficiency in taste and smell was assessed by two different questionnaires after a median of 100 and 244 days after first positive RT-PCR test. SARS-CoV-2-specific antibody levels were measured with the iFlash-SARS-CoV-2 assay. After 100 days a psychophysical screening test for olfactory and gustatory dysfunction was administered. 30 of 44 (68.2%) participants reported a chemosensory dysfunction (14 quantitative, 6 qualitative, 10 quantitative, and qualitative) during COVID-19, eleven (25.0%) participants (1 quantitative, 7 qualitative, 3 quantitative, and quantity) after 100 days, and 14 (31.8%) participants (1 quantitative, 10 qualitative, 3 quantitative and qualitative) after 244 days. Four (9.1%) participants, who were symptom-free after 100 days reported now recently arisen qualitative changes. Serological and T-cell analysis showed no correlation with impairment of taste and smell. In conclusion, qualitative changes can persist for several months and occur as late-onset symptoms months after full recovery from COVID-19-induced quantitative losses in taste and smell.

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