[Preparation and immungenicity of recombinant protein containing intramolecular adjuvant in SARS-CoV-2 RBD domain].

A fusion protein containing a tetanus toxin peptide, a tuftsin peptide and a SARS-CoV-2S protein receptor-binding domain (RBD) was prepared to investigate the effect of intramolecular adjuvant on humoral and cellular immunity of RBD protein. The tetanus toxin peptide, tuftsin peptide and S protein RBD region were connected by a flexible polypeptide, and a recombinant vector was constructed after codon optimization. The recombinant S-TT-tuftsin protein was prepared by prokaryotic expression and purification. BALB/c mice were immunized after mixed with aluminum adjuvant, and the humoral and cellular immune effects were evaluated. The recombinant S-TT-tuftsin protein was expressed as an inclusion body, and was purified by ion exchange chromatography and renaturated by gradient dialysis. The renaturated protein was identified by Dot blotting and reacted with serum of descendants immunized with SARS-CoV-2 subunit vaccine. The results showed that the antibody level reached a plateau after 35 days of immunization, and the serum antibody ELISA titer of mice immunized with recombinant protein containing intramolecular adjuvant was up to 1:66 240, which was significantly higher than that of mice immunized with S-RBD protein (P < 0.05). At the same time, the recombinant protein containing intramolecular adjuvant stimulated mice to produce a stronger lymphocyte proliferation ability. The stimulation index was 4.71±0.15, which was significantly different from that of the S-RBD protein (1.83±0.09) (P < 0.000 1). Intramolecular adjuvant tetanus toxin peptide and tuftsin peptide significantly enhanced the humoral and cellular immune effect of the SARS-CoV-2 S protein RBD domain, which provideda theoretical basis for the development of subunit vaccines for SARS-CoV-2 and other viruses.

Multi-target mechanisms against coronaviruses of constituents from Chinese Dagang Tea revealed by experimental and docking studies.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Eurya chinensis（Chinese Dagang Tea）have been consumed as herbal tea for centuries in Guangdong, China, and have also been used to prevent influenza and treat colds and fevers in traditional Chinese medicine. However, there are no reports on the chemical profile and efficacy of its leaves for the treatment of fever and viral infections. MATERIALS AND METHODS: The chemical constituents of Eurya chinensis leaves were isolated and identified by phytochemical study and spectroscopic data, E. chinensis extracts and compounds were evaluated for their antiviral activities by cytopathic effect (CPE) reduction and antibody-based EC50 assay. The antiviral effect of the main component was confirmed by immunofluorescence and transmission electron microscopy. Virtual screening and docking enzyme inhibition experiments were performed to analyze the anti-coronavirus mechanisms of the compounds from E. chinensis leaves. RESULTS: In this study, we found for the first time that E. chinensis leaf extract exhibited inhibitory effects against coronaviruses HCoV-OC43 in vitro. Among 23 monomer compounds isolated from E. chinensis leaf extract, the triterpenoids (betulinic acid, α-amyrin) and the flavonoids (naringenin, eriodictyol and quercetin) showed marked antiviral activity. Microscopic optical analyses further demonstrated that betulinic acid can remove virus particles from HCoV-OC43 infected cells. Virtual screening and docking analysis towards the coronavirus in vogue revealed that betulinic acid was able to bind well to PLpro and Nsp14N7-MTase, and that the flavonoids prefer to bind with PLpro, Nsp3MES, NspP14N7-MTase, Nsp16GTA, and Nsp16SAM. The enzyme inhibition experiments demonstrated that betulinic acid (1) exhibited significant inhibition of PLpro and N7-MTase activity of SARS-CoV-2. CONCLUSION: This study proposes E. chinensis and its triterpenoids and flavonoids as promising potential treatments for coronaviruses.

Preparation of different fragments of SARS-co V-2 urine protein and its application in fluorescent layer system

Expression and purification of different fragments of the new coronavirus nucleocapsid (N) protein, establish a new coronavirus total antibody fluorescence immunochromatographic method and evaluate the influence of different protein fragments on the method. Using bioinformatics technology to analyze, synthesize, express and purify the N protein sequence, prepare different N protein fragments;use 1-ethyl-(3-dimethylaminopropyl) carbodiimide (1-( 3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) method of fluorescent microspheres coupled with antigen was established to establish a sandwich fluorescence chromatography antibody detection method, and the performance was evaluated respectively. In the prepared 4 N protein fragments, the full-length N protein (N419) is preferably coated, and N412 is labeled with 0.5mol/L NaCl as the optimal combination;the 91-120th amino acid (N412) of the N-terminus of the N antigen is deleted It can reduce 87.5% of non-specific interference;the linear range is 0.312-80U/L, the lowest detection limit is 0.165U/L, and the accuracy is above 95%. The fluorescence immunochromatographic detection method for total antibodies of the new coronavirus established by pairing the N protein fragments has a total coincidence rate of 98% compared with the Guangzhou Wanfu test strip. The improvement provides experimental basis and reference.

[Preparation of different fragments of SARS-CoV-2 N protein and its application in fluorescence chromatography].

Different fragments of SARS-CoV-2 nucleocapsid (N) protein were expressed and purified, and a fluorescence immunochromatography method for detection of SARS-CoV-2 total antibody was established. The effect of different protein fragments on the performance of the method was evaluated. The N protein sequence was analyzed by bioinformatics technology, expressed in prokaryotic cell and purified by metal ion affinity chromatography column. Different N protein fragments were prepared for comparison. EDC reaction was used to label fluorescence microsphere on the synthesized antigen to construct sandwich fluorescence chromatography antibody detection assay, and the performance was systemically evaluated. Among the 4 prepared N protein fragments, the full-length N protein (N419) was selected as the optimized coating antigen, N412 with 0.5 mol/L NaCl was used as the optimal combination; deleting 91-120 amino acids from the N-terminal of N412 reduced non-specific signal by 87.5%. the linear range of detection was 0.312-80 U/L, the limit of detection was 0.165 U/L, and the accuracy was more than 95%. A fluorescence immunochromatographic detection method for analysis of SARS-CoV-2 total antibody was established by pairing N protein fragments. The detection result achieved 98% concordance with the commercially available Guangzhou Wanfu test strip, which is expected to be used as a supplementary approach for detection of SARS-CoV-2. The assay could also provide experimental reference for improving the performance of COVID-19 antibody detection reagents.

The efficacy and safety of Chinese traditional medicine injections on patients with coronavirus disease 2019: A protocol for systematic review and meta analysis.

INTRODUCTION: The pandemic caused by the coronavirus disease 2019 (COVID-19) infection has exposed vulnerable populations to an unprecedented global health crisis. Research reported that Chinese traditional medicine injections were used in patients with COVID-19 infection and showed significant effects, and there have been no systematic review and meta-analyses to investigate the effects and safety of Chinese traditional medicine injections. MATERIALS AND METHODS: This systematic review and meta-analysis protocol is based on the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 statement. The literature search will involve Cochran library, Web of science, PubMed, MEDLINE, Embase, China Biology Medicine Database, China National Knowledge Infrastructure Database, VIP, Wang Fang database, and China Clinical Trial Registration Center for articles and research published form December 2019. This search will include randomized controlled trials and nonrandomized studies. The Cochrane Collaboration's tool for randomized controlled trial studies and the Quality Assessment Tool for Quantitative Studies for nonrandomized studies will be used to assess the risk of bias among the studies included in the systematic review. Review Manager 5.3 software will be used for the meta-analysis, and odds ratio are calculated as the primary outcomes. Subgroup analyses will then be performed based on the characteristics of the interventions and populations included in the studies examined. ETHICS AND DISSEMINATION: This systematic review protocol is designed to provide evidence regarding the effects and safety of Chinese traditional medicine injections on patients with COVID-19, such evidence may be useful and important for clinical treatment decisions. The results should be disseminated through publication in a peer-reviewed journal. Since the data and results used in the systematic review will be extracted exclusively from published studies, approval from an ethics committee will not be required.

The effectiveness and safety of traditional Chinese medicine for the treatment of children with COVID-19.

INTRODUCTION: With the widespread spread of novel coronavirus pneumonia, more and more countries have been affected. Some research reports have shown that traditional Chinese medicine has a significant effect on COVID-19 infection, and the treatment of traditional Chinese medicine is used in some special people, such as children. At present, there is a lack of high-quality systematic reviews on the safety and efficacy of using Chinese medicine to treat children with novel coronavirus pneumonia. MATERIALS AND METHODS: We will search Cochran library, MEDLINE, EMBASE, China National Knowledge Infrastructure Database (CNKI), China Biomedical Database (CBM), VIP Database (VIP), and Wanfang database for research. This study includes randomized controlled trials (RCTs) and non-RCTs, and uses the Cochrane systematic review to review the safety and efficacy of traditional Chinese medicine in preventing and treating children with novel coronavirus pneumonia. RCT research tools and quantitative research quality assessment tools for non-randomized studies will be used to assess the risk of bias in studies included in the systematic review. We will use Revman 5.3 software for meta-analysis, the main result is odds ratio, and then a subgroup analysis will be performed based on the age, intervention degree, and disease severity of the patients reviewed. ETHICS AND DISSEMINATION: This systematic review protocol is designed to provide evidence regarding the effectiveness and safety of traditional Chinese medicine for the treatment of children with COVID-19, such evidence may be useful and important for clinical treatment decisions. The results should be disseminated through publication in a peer-reviewed journal. Since the data and results used in the systematic review will be extracted exclusively from published studies, approval from an ethics committee will not be required. REGISTRATION INFORMATION: PROSPERO CRD42020179150.