Rapid Point-of-Care Assay by SERS Detection of SARS-CoV-2 Virus and Its Variants.

Addressing the spread of coronavirus disease 2019 (COVID-19) has highlighted the need for rapid, accurate, and low-cost diagnostic methods that detect specific antigens for SARS-CoV-2 infection. Tests for COVID-19 are based on reverse transcription PCR (RT-PCR), which requires laboratory services and is time-consuming. Here, by targeting the SARS-CoV-2 spike protein, we present a point-of-care SERS detection platform that specifically detects SARS-CoV-2 antigen in one step by captureing substrates and detection probes based on aptamer-specific recognition. Using the pseudovirus, without any pretreatment, the SARS-CoV-2 virus and its variants were detected by a handheld Raman spectrometer within 5 min. The limit of detection (LoD) for the pseudovirus was 124 TU µL-1 (18 fM spike protein), with a linear range of 250-10,000 TU µL-1. Moreover, this assay can specifically recognize the SARS-CoV-2 antigen without cross reacting with specific antigens of other coronaviruses or influenza A. Therefore, the platform has great potential for application in rapid point-of-care diagnostic assays for SARS-CoV-2.

Robust neutralization assay based on SARS-CoV-2 S-protein-bearing vesicular stomatitis virus (VSV) pseudovirus and ACE2-overexpressing BHK21 cells.

The global pandemic of coronavirus disease 2019 (COVID-19) is a disaster for human society. A convenient and reliable neutralization assay is very important for the development of vaccines and novel drugs. In this study, a G protein-deficient vesicular stomatitis virus (VSVdG) bearing a truncated spike protein (S with C-terminal 18 amino acid truncation) was compared to that bearing the full-length spike protein of SARS-CoV-2 and showed much higher efficiency. A neutralization assay was established based on VSV-SARS-CoV-2-Sdel18 pseudovirus and hACE2-overexpressing BHK21 cells (BHK21-hACE2 cells). The experimental results can be obtained by automatically counting the number of EGFP-positive cells at 12 h after infection, making the assay convenient and high-throughput. The serum neutralizing titer measured by the VSV-SARS-CoV-2-Sdel18 pseudovirus assay has a good correlation with that measured by the wild type SARS-CoV-2 assay. Seven neutralizing monoclonal antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 S protein were obtained. This efficient and reliable pseudovirus assay model could facilitate the development of new drugs and vaccines.

[Usage of ethnomedicine on COVID-19 in China].

In December 2019, an outbreak of viral pneumonia began in Wuhan, Hubei Province, which caused the spread of infectious pneumonia to a certain extent in China and neighboring countries and regions, and triggered the epidemic crisis. The coronavirus disease 2019(COVID-19) is an acute respiratory infectious disease listed as a B infectious disease, which is managed according to standards for A infectious disease. Traditional Chinese medicine and integrated traditional Chinese and Western medicine have played an active role in the prevention and control of this epidemic. China's ethnomedicine has recognized infectious diseases since ancient times, and formed a medical system including theory, therapies, formula and herbal medicines for such diseases. Since the outbreak of the COVID-19 epidemic, Tibet Autonomous Region, Qinghai Province, Inner Mongolia Autonomous Region, Xinjiang Uygur Autonomous Region and Chuxiong Autonomous Prefecture of Yunnan, Qiandongnan Autonomous Prefecture of Guizhou have issued the prevention and control programs for COVID-19 using Tibetan, Mongolian, Uygur, Yi and Miao medicines. These programs reflect the wisdom of ethnomedicine in preventing and treating diseases, which have successfully extracted prescriptions and preventive measures for the outbreak of the epidemic from their own medical theories and traditional experiences. In this paper, we summarized and explained the prescriptions and medicinal materials of ethnomedicine in these programs, and the origin of Tibetan medicine prescriptions and Mongolian medicine prescriptions in ancient books were studied. These become the common characteristics of medical prevention and treatment programs for ethnomedicine to formulate therapeutic programs under the guidance of traditional medicine theories, recommend prescriptions and prevention and treatment methods with characteristics of ethnomedicine, and focus on the conve-nience and standardization. However, strengthening the support of science and technology and the popularization to the public, and improving the participation of ethnomedicine in national public health services and the capacity-building to deal with sudden and critical diseases are key contents in the development of ethnomedicine in the future.

Serology characteristics of SARS-CoV-2 infection since exposure and post symptom onset

BACKGROUND: Timely diagnosis of SARS-CoV-2 infection is a prerequisite for treatment and prevention. The serology characteristics and complement diagnosis value of the antibody test to RNA test need to be demonstrated. METHOD: Serial sera of 80 patients with PCR-confirmed COVID-19 were collected at the First Affiliated Hospital of Zhejiang University, China. Total antibody (Ab), IgM and IgG antibodies against SARS-CoV-2 were detected, and the antibody dynamics during the infection were described. RESULTS: The seroconversion rates for Ab, IgM and IgG were 98.8%, 93.8% and 93.8%, respectively. The first detectible serology marker was Ab, followed by IgM and IgG, with a median seroconversion time of 15, 18 and 20 days post exposure (d.p.e) or 9, 10 and 12 days post onset (d.p.o), respectively. The antibody levels increased rapidly beginning at 6 d.p.o. and were accompanied by a decline in viral load. For patients in the early stage of illness (0-7 d.p.o), Ab showed the highest sensitivity (64.1%) compared to IgM and IgG (33.3% for both, p<0.001). The sensitivities of Ab, IgM and IgG increased to 100%, 96.7% and 93.3% 2 weeks later, respectively. When the same antibody type was detected, no significant difference was observed between enzyme-linked immunosorbent assays and other forms of immunoassays. CONCLUSIONS: A typical acute antibody response is induced during SARS-CoV-2 infection. Serology testing provides an important complement to RNA testing in the later stages of illness for pathogenic specific diagnosis and helpful information to evaluate the adapted immunity status of patients.

[Intervention mechanism of Qingwen Baidu Yin on cytokine storm based on network pharmacology].

The aim of this paper was to explore the intervention mechanism of Qingwen Baidu Yin in cytokine storm based on network pharmacology. TCMSP and TCMIP V2.0 server were used to predict all chemical components and action targets of Qingwen Baidu Yin. Diseases that could be treated by Qingwen Baidu Yin were predicted through Enrichr database. A compound target interaction(PPI) network diagram was constructed using STRING 11.0. OmicShare was used to analyzed the gene ontology(GO) enrichment and enrichment of the Kyoto encyclopedia of genes and genomes(KEGG) pathway of core targets. Component-target-path network diagram was constructed with Cytoscape 3.6.0 software. After analysis of the database, 267 compounds were screened for Qingwen Baidu Yin, involving 1 450 targets, and a protein interaction network was constructed. Total 219 core target proteins were predicted, such as NFKB1, STAT1, RAF1, IL2, JAK1, IL6, TNF, BCL2 and other important targets, and 221 core target pathways were enriched, including cancer pathway, Kaposi's sarcoma-associated herpes virus infection, chemokine signal pathway, PI3 K-AKT signal pathway, EB virus infection, virus carcinogenesis and T cell receptor signaling pathways, a collection of which were highly related to cytokine storms. GO annotation analysis suggested that Qingwen Baidu Yin Decoction may exert therapeutic effects by regulating protein phosphorylation, cell response to cytokine stimulation, cell proliferation, inflammatory response, transmembrane receptor protein tyrosine kinase signaling pathway, and cytokine-mediated signaling pathways. This study revealed potential active components of Qingwen Baidu Yin in defending against cytokine storm and its possible mechanism of action, and provided theoretical basis and technical support for further clinical application of this prescription.