Development and clinical value evaluation of IgM-IgG antibody detection kit for SARS-CoV-2 infection in 15 cases. (Special Issue: Spatio-temporal dynamics analysis, risk assessment and emergency management for COVID-19 epidemic.) [Chinese]

Objective: To develop a colloidal gold kit for rapid detection of IgM-IgG antibodies of SARS-CoV-2, optimize the development and application strategy, and investigate the diagnostic value of SARS-CoV-2 IgM-IgG antibodies by detecting serum of clinically confirmed patients.

Effects of Micro Architectural Environmental Interventions on Handwashing Compliance of Adolescents: A School-Based Intervention Trial.

PURPOSE: Aimed to explore more practical interventions for handwashing compliance (HWC) and protect the minor' health with the pandemic background, this study tested whether micro architectural interventions would promote HWC of adolescents through active experience. BACKGROUND: Despite the well-documented benefits of handwashing (HW), low compliance is common among adolescents. HW space in schools has always been treated as attached spaces of little matter, which is unfavorable to public health. According to environment behavior perspective, personal motivation of HWC may be motivated by active environment. METHOD: A school-based investigation and a 30-week environmental behavior experiment were conducted when students returned to school after the COVID-19 pandemic closure in 2020 in China to evaluate the effects of active environment interventions selected by previous survey on promoting adolescents' HW rate. Digital infrared counters were used to unobtrusively document their behavior. RESULTS: Results in summer revealed a positive effect on all intervention groups. The effects of combined interventions were higher than the effect of any single intervention. However, HW rates of all groups declined sharply in the coldest month and the between-group differences decreased. Significant correlations were found between HW rates and satisfaction with the intervention schemes. CONCLUSIONS: Findings suggest that architectural environmental intervention may potentially be a positive, friendly, and one-time investment mean to expand the HWC intervention scope from passive policies to positive experience, and HW space design for adolescents should be treated as a public health strategy.

Screening of HLA-A restricted T cell epitopes of SARS-CoV-2 and induction of CD8+ T cell responses in HLA-A transgenic mice (preprint)

While SARS-CoV-2-specific T cells have been characterized to play essential roles in host immune protection in COVID-19 patients, few researches focus on the functional validation of T cell epitopes and development of vaccines inducing specific T cell responses. In this study, 120 CD8 T cell epitopes from E, M, N, S and RdRp proteins of SARS-CoV-2 were validated by on-silicon prediction, DC-peptide-PBL costimulation with PBMCs of healthy donors and HLA-A molecule competitive binding experiments. Among them, 110, 15, 6, 14 and 12 epitopes were highly homologous with SARS-CoV, OC43, NL63, HKU1, and 229E, respectively. Thirty-one epitopes restricted by HLA-A2 molecule were used to generate peptide cocktail vaccines in combination with Poly(I:C), R848 or polylactic-co-glycolic acid nanoparticles, which elicited robust specific CD8 T cell responses in wild-type and HLA-A2/DR1 transgenic mice. Seven of the 31 epitopes were found to be cross-presented by HLA-A2 and H-2K/Db molecules. These data have provided a library of SARS-CoV-2 CD8 T cell epitopes which restricted by a series of high-frequency HLA-A allotypes and covered broad population in Asia, and initially confirmed the feasibility of human MHC class I molecule-restricted SARS-CoV2 epitope peptide cocktail vaccines, thus will facilitate the development of T cell epitope vaccines and specific cellular function detection kits.

Fibrinolysis influences SARS-CoV-2 infection in ciliated cells (preprint)

Rapid spread of COVID-19 has caused an unprecedented pandemic worldwide, and an inserted furin site in SARS-CoV-2 spike protein (S) may account for increased transmissibility. Plasmin, and other host proteases, may cleave the furin site of SARS-CoV-2 S protein and γ subunits of epithelial sodium channels (γ ENaC), resulting in an increment in virus infectivity and channel activity. As for the importance of ENaC in the regulation of airway surface and alveolar fluid homeostasis, whether SARS-CoV-2 will share and strengthen the cleavage network with ENaC proteins at the single-cell level is urgently worthy of consideration. To address this issue, we analyzed single-cell RNA sequence (scRNA-seq) datasets, and found the PLAU (encoding urokinase plasminogen activator), SCNN1G (γENaC), and ACE2 (SARS-CoV-2 receptor) were co-expressed in alveolar epithelial, basal, club, and ciliated epithelial cells. The relative expression level of PLAU, TMPRSS2, and ACE2 were significantly upregulated in severe COVID-19 patients and SARS-CoV-2 infected cell lines using Seurat and DESeq2 R packages. Moreover, the increments in PLAU, FURIN, TMPRSS2, and ACE2 were predominately observed in different epithelial cells and leukocytes. Accordingly, SARS-CoV-2 may share and strengthen the ENaC fibrinolytic proteases network in ACE2 positive airway and alveolar epithelial cells, which may expedite virus infusion into the susceptible cells and bring about ENaC associated edematous respiratory condition.

Significant reduced traffic in Beijing failed to relieve haze pollution during the COVID-19 lockdown: implications for haze mitigation (preprint)

The COVID-19 outbreak greatly limited human activities and reduced primary emissions particularly from urban on-road vehicles, but coincided with Beijing experiencing pandemic haze, raising the public concerns of the validity and effectiveness of the imposed traffic policies to improve the air pollution. Here, we explored the relationship between local vehicle emissions and the winter haze in Beijing before and during the COVID-19 lockdown period based on an integrated analysis framework, which combines a real-time on-road emission inventory, in-situ air quality observations and a localized chemical transport modeling system. We found that traffic emissions decreased substantially affected by the pandemic, with a higher reduction for NOx (75.9%, 125.3 Mg/day) compared to VOCs (53.1%, 52.9 Mg/day). Unexpectedly, our results show that the imbalanced emission abatement of NOx and VOCs from vehicles led to a significant rise of the atmospheric oxidizing capacity in urban areas, but only resulting in modest increases in secondary aerosols due to the inadequate precursors. However, the enhanced oxidizing capacity in the surrounding regions greatly increased the secondary particles with relatively abundant precursors, which is mainly responsible for Beijing haze during the lockdown period. Our results indicate that the winter haze in Beijing was insensitive to the local vehicular emissions reduction due to the complicated nonlinear response of the fine particle and air pollutant emissions. We suggest mitigation policies should focus on accelerating VOC and NH3 emissions reduction and synchronously controlling regional sources to release the benefits on local traffic emission control.