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To evaluate vaccine-induced humoral and cell-mediated immunity at 6 months after completion of two doses of BNT162b2 vaccination, immunoglobulin G against SARS-CoV-2 spike protein (SP IgG), 50% neutralizing antibody (NT

We are amid the historic coronavirus infectious disease 2019 (COVID-19) pandemic. Imbalances in the accessibility of vaccines, medicines, and diagnostics among countries, regions, and populations, and those in war crises, have been problematic. Nanobodies are small, stable, customizable, and inexpensive to produce. Herein, we present a panel of nanobodies that can detect the spike proteins of five SARS-CoV-2 variants of concern (VOCs) including Omicron. Here we show via ELISA, lateral flow, kinetic, flow cytometric, microscopy, and Western blotting assays that our nanobodies can quantify the spike variants. This panel of nanobodies broadly neutralizes viral infection caused by pseudotyped and authentic SARS-CoV-2 VOCs. Structural analyses show that the P86 clone targets epitopes that are conserved yet unclassified on the receptor-binding domain (RBD) and contacts the N-terminal domain (NTD). Human antibodies rarely access both regions; consequently, the clone buries hidden crevasses of SARS-CoV-2 spike proteins that go undetected by conventional antibodies., 新型コロナウイルスを中和するアルパカ抗体 --オミクロンを含む全ての変異株に有効--. 京都大学プレスリリース. 2022-07-14.

OBJECTIVES: Gastrointestinal endoscopy (GIE) is useful for the early detection and treatment of many diseases; however, GIE is considered a high-risk procedure in the coronavirus disease 2019 (COVID-19) pandemic era. This study aimed to explore the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity in saliva and gastrointestinal fluids to which endoscopy medical staff are exposed. METHODS: The study was a single-center cross-sectional study. From June 1 to July 31, 2020, all patients who underwent GIE at Yokohama City University Hospital were registered. All patients provided 3 mL of saliva. For upper GIE, 10 mL of gastric fluid was collected through the endoscope. For lower GIE, 10 mL of intestinal fluid was collected through the endoscope. The primary outcome was the positive rate of SARS-CoV-2 in saliva and gastrointestinal fluids. We also analyzed serum-specific antibodies for SARS-CoV-2 and patients' background information. RESULTS: A total of 783 samples (560 upper GIE and 223 lower GIE samples) were analyzed. Polymerase chain reaction (PCR) on saliva samples did not show any positive results in either upper or lower GIE samples. However, 2.0% (16/783) of gastrointestinal fluid samples tested positive for SARS-CoV-2. No significant differences in age, sex, purpose of endoscopy, medication, or rate of antibody test positivity were found between PCR positive and PCR negative cases. CONCLUSIONS: Asymptomatic patients, even those with no detectable virus in their saliva, had SARS-CoV-2 in their gastrointestinal tract. Endoscopy medical staff should be aware of infection when performing procedures. The study was registered as UMIN000040587.

The uncontrolled spread of the COVID-19 pandemic has led to the emergence of different SARS-CoV-2 variants across the globe. The ongoing global vaccination strategy to curtail the COVID-19 juggernaut, is threatened by the rapidly spreading Variants of Concern (VOC) and other regional mutants, which are less responsive to neutralization by infection or vaccine derived antibodies. We have previously developed the hiVNT system which detects SARS-CoV-2 neutralizing antibodies in sera in less than three hours. In this study, we modify the hiVNT for rapid qualitative screening of neutralizing antibodies (nAb) to multiple VOC of SARS-CoV-2, and assess the neutralizing efficacy of the BNT162b2 mRNA vaccine on seven epidemiologically relevant SARS-CoV-2 variants. Here we show that the BNT162b2 mRNA vaccine can activate humoral immunity against the major SARS-CoV-2 mutants that are currently in circulation. Albeit a small sample size, we observed that one dose of vaccine was sufficient to elicit a protective humoral response in previously infected people. Using a panel of seven SARS-CoV-2 variants and a single prototype virus, our modified hiVNT would be useful for large-scale community wide testing to detect protective immunity that may confer vaccine/immune passport in the ongoing COVID-19 pandemic.

The pandemic of COVID-19 is spreading unchecked due to the lack of effective antiviral measures. Silver nanoparticles (AgNP) have been studied to possess antiviral properties and are presumed to inhibit SARS-CoV-2. Due to the need for an effective agent against SARS-CoV-2, we evaluated the antiviral effect of AgNPs. We evaluated a plethora of AgNPs of different sizes and concentration and observed that particles of diameter around 10 nm were effective in inhibiting extracellular SARS-CoV-2 at concentrations ranging between 1 and 10 ppm while cytotoxic effect was observed at concentrations of 20 ppm and above. Luciferase-based pseudovirus entry assay revealed that AgNPs potently inhibited viral entry step via disrupting viral integrity. These results indicate that AgNPs are highly potent microbicides against SARS-CoV-2 but should be used with caution due to their cytotoxic effects and their potential to derange environmental ecosystems when improperly disposed., Highlights • Silver nanoparticles inhibit extracellular SARS-CoV-2. • 2–15 nm size particles showed robust inhibition of SARS-CoV-2. • SARS-CoV-2 was potently inhibited at concentrations above 1 ppm. • Naked Silver nanoparticles exhibited cytotoxicity from 20 ppm onwards.

BackgroundLevels of 50% neutralizing titer (NT50) reflect a vaccine-induced humoral immunity after the vaccination against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Measurements of NT50 are difficult to implement in large quantities. A high-throughput laboratory test is expected for determining the level of herd immunity against SARS-CoV-2.MethodsWe analyzed samples from 168 Japanese healthcare workers who had completed two doses of the BNT162b2 vaccine. We analyzed immunoglobulin G (IgG) index values against spike protein (SP) using automated chemiluminescent enzyme immunoassay system AIA-CL and analyzed the background factors affecting antibody titer. SP IgG index was compared with 50% neutralization titers.ResultsThe median SP IgG index values of the subjects (mean age = 43 years; 75% female) were 0.1, 1.35, 60.80, and 97.35 before and at 2, 4, and 6 weeks after the first dose, respectively. At 4 and 6 weeks after the first dose, SP IgG titers were found to have positive correlation with NT50 titer (r=0.7535 in 4 weeks; r=0.4376 in 6 weeks). Proportions of the SP IgG index values against the Alpha, Beta, Gamma, and Delta variants compared with the original strain were 2.029, 0.544, 1.017, and 0.6096 respectively. Older age was associated with lower SP IgG titer index 6 weeks after the first dose.ConclusionsSP IgG index values were raised at 3 weeks after two doses of BNT162b2 vaccination and have positive correlation with NT50. SP IgG index values were lower in the older individuals and against Beta and Delta strain.

Background Many health care workers around the world tackled with COVID-19, however sadly, the infection of many medical care workers were reported. To reduce the risk of infection, we launched selected team (Team COVID) of non-specialists and brought in active telemedicine method and computed tomography (CT)-first protocol. We describe our actual practice and the health status of medical doctors dealing with COVID-19 patients. Methods Between April 17, 2020 and May 24, 2020, 10 doctors worked with COVID-19 patients as part of Team COVID. The Team COVID doctors used a CT-first triage protocol for outpatients and telemedicine for inpatients and outpatients. We evaluated paired serum-specific antibodies for SARS-CoV-2 at the initial and end of the study duration and PCR results for SARS-CoV-2 at the end of the study duration. Furthermore, 36-item short-form of the Medical Outcome Study Questionnaire (SF-36) at the beginning and end of the study period were evaluated. Results Ten doctors worked as Team COVID: seven internal medicine doctors and three surgeons. During the study period, Team COVID treated 165 individuals in the outpatient clinic and isolated hospitalized patients for 315 person-days. There were no positive results of serum-specific antibody testing and PCR testing for SARS-CoV-2 in Team COVID doctors. Furthermore, the SF-36 showed no deterioration in physical and mental QOL status. No in-hospital infection occurred during the study period. Conclusions The Team COVID fulfilled the treatment using the active telemedicine and CT-first triage protocol without in hospital infection and excess stress. The combination strategy seems acceptable for both the protection and stress relief among the medical staff.

ObjectiveSerological tests for COVID-19 have been instrumental in studying the epidemiology of the disease. However, the performance of the currently available tests is plagued by the problem of variability. We have developed a high-throughput serological test capable of simultaneously detecting total immunoglobulins (Ig) and immunoglobulin G (IgG) against two of the most immunologically relevant SARS-CoV-2 antigens, nucleocapsid protein (NP) and spike protein (SP) and report its performance in detecting COVID-19 in clinical samples.MethodsWe designed and prepared reagents for measuring NP-IgG, NP-Total Ig, SP-IgG, and SP-Total Ig (using N-terminally truncated NP (ΔN-NP) or receptor-binding domain (RBD) antigen) on the advanced chemiluminescence enzyme immunoassay system TOSOH AIA-CL. After determining the basal thresholds based on 17 sera obtained from confirmed COVID-19 patients and 600 negative sera. Subsequently, the clinical validity of the assay was evaluated using independent 202 positive samples and 1,000 negative samples from healthy donors.ResultsAll of the four test parameters showed 100% specificity individually (1,000/1,000; 95%CI, 99.63-100). The sensitivity of the assay increased proportionally to the elapsed time from symptoms onset, and all the tests achieved 100% sensitivity (153/153; 95%CI, 97.63-100) after 13 days from symptoms onset. NP-Total Ig was the earliest to attain maximal sensitivity among the other antibodies tested.ConclusionOur newly developed serological testing exhibited 100% sensitivity and specificity after 13 days from symptoms onset. Hence, it could be used as a reliable method for accurate detection of COVID-19 patients and to evaluate seroprevalence and possibly for surrogate assessment of herd immunity.

SARS-CoV-2 neutralizing antibodies confer protective immunity against reinfection. We have developed a rapid test for screening SARS-CoV-2 neutralization antibodies using genome-free virus-like particles incorporated with a small luciferase peptide, HiBiT. Their entry into LgBiT-expressing target cells reconstitutes NanoLuc luciferase readily detected by a luminometer. This newly developed HiBiT-tagged Virus-like particle-based Neutralization Test (hiVNT) can readily quantify SARS-CoV-2 neutralizing antibodies within three hours with a high-throughput in a low biosafety setting. Moreover, the neutralizing activity obtained from hiVNT was highly consistent with that measured by the conventional neutralization test using authentic SARS-CoV-2. Furthermore, antibody responses to both viral spike and nucleocapsid proteins correlated with the neutralization activity assessed by hiVNT. Our newly-developed hiVNT could be instrumental to survey individuals for the presence of functional neutralizing antibody against SARS-CoV-2.

Background The coronavirus disease 2019 (COVID-19) pandemic rapidly increases the use of mechanical ventilation (MV). Such cases further require extracorporeal membrane oxygenation (ECMO) and have a high mortality. Objective We aimed to identify prognostic biomarkers pathophysiologically reflecting future deterioration of COVID-19. Methods Clinical, laboratory, and outcome data were collected from 102 patients with moderate to severe COVID-19. Interleukin (IL)-6 level and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA copy number in plasma were assessed with ELISA kit and quantitative PCR. Results Twelve patients died or required ECMO owing to acute respiratory distress syndrome despite the use of MV. Among various variables, a ratio of oxygen saturation to fraction of inspired oxygen (SpO2/FiO2), IL-6, and SARS-CoV-2 RNA on admission before intubation were strongly predictive of fatal outcomes after the MV use. Moreover, among these variables, combining SpO2/FiO2, IL-6, and SARS-CoV-2 RNA showed the highest accuracy (area under the curve: 0.934). In patients with low SpO2/FiO2 (< 261), fatal event-rate after the MV use at the 30-day was significantly higher in patients with high IL-6 (> 49 pg/mL) and SARS-CoV-2 RNAaemia (> 1.5 copies/μL) compared to those with high IL-6 or RNAaemia or without high IL-6 and RNAaemia (88% vs. 22% or 8%, log-rank test P = 0.0097 or P < 0.0001, respectively). Conclusions Combining SpO2/FiO2 with high IL-6 and SARS-CoV-2 RNAaemia which reflect hyperinflammation and viral overload allows accurately and before intubation identifying COVID-19 patients at high risk for ECMO use or in-hospital death despite the use of MV.

The ongoing coronavirus disease 2019 (COVID-19) pandemic is a major global public health concern. Although rapid point-of-care testing for detecting viral antigen is important for management of the outbreak, the current antigen tests are less sensitive than nucleic acid testing. In our current study, we produce monoclonal antibodies (mAbs) that exclusively react with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and exhibit no cross-reactivity with other human coronaviruses, including SARS-CoV. Molecular modeling suggests that the mAbs bind to epitopes present on the exterior surface of the nucleocapsid, making them suitable for detecting SARS-CoV-2 in clinical samples. We further select the optimal pair of anti-SARS-CoV-2 nucleocapsid protein (NP) mAbs using ELISA and then use this mAb pair to develop immunochromatographic assay augmented with silver amplification technology. Our mAbs recognize the variants of concern (501Y.V1-V3) that are currently in circulation. Because of their high performance, the mAbs of this study can serve as good candidates for developing antigen detection kits for COVID-19., Graphical abstract, In this study, Yamaoka et al. report their highly specific, epitope-characterized monoclonal antibodies that exclusively detect SARS-CoV-2. These monoclonal antibodies, when used in a lateral flow immunoassay coupled with silver amplification, enhance the performance of rapid antigen detection tests for COVID-19.