Activation of SARS-CoV-2 by trypsin-like proteases in the clinical specimens of patients with COVID-19

SARS-CoV-2 enters host cells through the angiotensin converting enzyme 2 (ACE2) receptor and/or transmembrane protease, serine 2 (TMPRSS2). Serine proteases, such as TMPRSS2 and trypsin, promote viral entry. In this study, we investigated whether proteases increased SARS-CoV-2 infectivity using pseudotyped viruses and clinical specimens from patients with COVID-19. First, we investigated how trypsin increased infectivity using the pseudotyped virus. Our findings revealed that trypsin increased infectivity after the virus was adsorbed on the cells, but no increase in infectivity was observed when the virus was treated with trypsin. We examined the effect of trypsin on SARS-CoV-2 infection in clinical specimens and found that the infectivity of the SARS-CoV-2 delta variant increased 36,000-fold after trypsin treatment. By contrast, the infectivity of SARS-CoV-2 omicron variant increased to less than 20-fold in the clinical specimens. Finally, infectivity of clinical specimens containing culture supernatants of Fusobacterium necrophorum was increased from several- to 10-fold. Because SARS-CoV-2 infectivity increases in the oral cavity, which may contain anaerobic bacteria, keeping the oral cavities clean may help prevent SARS-CoV-2 infection. ImportanceIn this study, we examined whether trypsin-like proteases increased the infectivity of SARS-CoV-2. We found that trypsin-like proteases increased the infectivity of both the pseudotyped viruses and the live virus in the clinical specimens. The increase in infectivity was significantly higher for the delta than the omicron variant. A large amount of protease in the oral cavity during SARS-CoV-2 infection is expected to increase infectivity. Therefore, keeping the oral cavity clean is important for preventing infection.

Correlation of the commercial anti-SARS-CoV-2 receptor binding domain antibody test with the chemiluminescent reduction neutralizing test and possible detection of antibodies to emerging variants

BackgroundSerological tests are beneficial for recognizing the immune response against SARS-CoV-2. To identify protective immunity, optimization of the chemiluminescent reduction neutralizing test (CRNT), using pseudotyped SARS-CoV-2, is critical. Whether commercial antibody tests are comparably accurate is unknown. MethodsSerum samples collected before variants were locally found were obtained from confirmed COVID-19 patients (n = 74), confirmed non-COVID-19 individuals (n = 179), and unscreened individuals (suspected healthy individuals, n = 229). The convalescent phase was defined as the period after day 10 from disease onset. The CRNT against pseudotyped viruses displaying the wild-type spike protein and a commercially available anti-receptor binding domain (RBD) antibody test were assayed. The CRNT was also assayed, using South African (SA) and United Kingdom (UK)-derived variants. ResultsThe CRNT (cut off value, 50% inhibition) and the anti-RBD antibody test (cut off value, 0.8 U/mL) concurred regarding symptomatic COVID-19 patients in the convalescent phase and clearly differentiated between patients and suspected healthy individuals (sensitivity; 95.8% and 100%, specificity; 99.1% and 100%, respectively). Anti-RBD antibody test results correlated with neutralizing titer (r = 0.47, 95% CI 0.20-0.68). Compared with the wild-type, CRNT reduction was observed for the SA and UK-derived variants. Of the samples with [≥]100 U/mL by the anti-RBD antibody test, 77.8% and 88.9% showed [≥]50% neutralization against the UK and the SA variants, respectively. ConclusionThe CRNT and commercial anti-RBD antibody test effectively classified convalescent COVID-19 patients. The strong positive results using the commercial antibody test can reflect neutralizing activity against emerging variants.

Evaluation of Publicity Activities to the COVID-19 Website for Community Pharmacists / 医薬品情報学

Objective: The worldwide spread of the COVID-19 pandemic since 2020 led to a lack of information even at Japanese pharmacies, which are at the forefront of community medicine. Therefore, the Kyoto University Graduate School of Public Health Pharmacy Information Group has developed information materials related to COVID-19 for pharmacies0and released them on the COVID-19 countermeasure website, which was launched in haste. However, these days in the information society, the amount of information distributed is explosively expanding. Therefore, it is not possible to reach the target people just by publishing the countermeasure website. Therefore, we set up a public relations team to carry out publicity activities for pharmacists and analyzed the effectiveness of these activities by focusing on changes in the number of page views (PV) on the countermeasure website.Methods: PV and public relations(Facebook, industry media , e-mail) activities during the first 18 days(EARLY period), which is half of the total PV, and the remaining 164 days(MIDDLE period), covering 182 days from the day before the countermeasure website was opened. The changes in quantity were compared. Furthermore, we also compared the changes in the level of interest in the new coronavirus during the target period using Google Trends.Results: PV was remarkably large in the EARLY period, and the amount of public relations activity was generally concentrated in the EARLY period and PV. The number of searches for related words on Google Trends was almost the same as PV except for some. Conclusion: The study revealed the importance of establishing a pandemic countermeasure website for pharmacists at an appropriate time and conducting intensive public relations activities in the early stages.