ABSTRACT
Population antibody response is believed to be important in selection of new variant viruses. We identified that SARS-CoV-2 infections elicit a population immune response mediated by a lineage of VH1-69 germline antibodies. The representative antibody R1-32 targets a novel semi-cryptic epitope defining a new class of RBD targeting antibodies. Binding to this non-ACE2 competing epitope leading to spike destruction impairing virus entry. Based on epitope location, neutralization mechanism and analysis of antibody binding to spike variants we propose that recurrent substitutions at 452 and 490 are associated with immune evasion of this population antibody response. These substitutions, including L452R found in the Delta variant, disrupt interaction mediated by the VH1-69 specific hydrophobic HCDR2 to impair antibody-antigen association allowing variants to escape. Lacking 452/490 substitutions, the Omicron variant is sensitive to this class of antibodies. Our results provide new insights into SARS-CoV-2 variant genesis and immune evasion.
Subject(s)
COVID-19ABSTRACT
In recent years, the import of aquatic products at Zhanjiang port has continued to increase, which has effectively promoted the development of the local economy. However, unqualified imported aquatic products have occurred from time to time, and it has always been an important duty of the customs to control the safety of imported food. Especially with the continuous outbreak of novel coronavirus pneumonia epidemic situation since 2020, it is particularly important to ensure the quality and safety of imported aquatic products, especially the traceability of the products. This article focused on analyzing the characteristics and functions of blockchain technology, combining with the problems of traceability of imported aquatic products in Zhanjiang, combined blockchain technology with three-dimensional customs supervision, explored the establishment of customs blockchain supervision model, and analyzed and studied the feasibility of the application of blockchain in the traceability of imported aquatic products in Zhanjiang. The traceability supervision system including production enterprises, importers and exporters, third-party institutions, logistics, warehousing, banking, insurance and other stakeholders was constructed. Finally, relevant application exploration schemes were put forward, and it was expected to provide some reference for improving the quality of imported products and perfecting the construction of imported food safety traceability management system.
ABSTRACT
Objective: To observe distribution of traditional Chinese medicine(TCM) patterns and changes of peripheral blood cell count and chest imaging in mild and moderate COVID-19 patients.
ABSTRACT
The COVID-19 global pandemic and resulted lockdown policies have forced education in nearly every country to switch from a traditional co-located paradigm to a pure online 'distance learning from home' paradigm. Lying in the center of this learning paradigm shift is the emergence and wide adoption of distance communication tools and live streaming platforms for education. Here, we present a mixed-methods study on live streaming based education experience during the COVID-19 pandemic. We focus our analysis on Chinese higher education, carried out semi-structured interviews on 30 students, and 7 instructors from diverse colleges and disciplines, meanwhile launched a large-scale survey covering 6291 students and 1160 instructors in one leading Chinese university. Our study not only reveals important design guidelines and insights to better support current remote learning experience during the pandemic, but also provides valuable implications towards constructing future collaborative education supporting systems and experience after pandemic.
Subject(s)
COVID-19ABSTRACT
COVID-19, caused by SARS-CoV-2, is an acute self-resolving disease in most of the patients, but some patients can develop a severe illness or even death. To characterize the host responses and identify potential biomarkers during disease progression, we performed a longitudinal transcriptome analysis for peripheral blood mononuclear cells (PBMCs) collected from 4 COVID-19 patients at 4 different time points from symptom onset to recovery. We found that PBMCs at different COVID-19 disease stages exhibited unique transcriptome characteristics. SARS-CoV-2 infection dysregulated innate immunity especially type I interferon response as well as the disturbed release of inflammatory cytokines and lipid mediators, and an aberrant increase of low-density neutrophils may cause tissue damage. Activation of cell death, exhaustion and migratory pathways may lead to the reduction of lymphocytes and dysfunction of adaptive immunity. COVID-19 induced hypoxia may exacerbate disorders in blood coagulation. Based on our analysis, we proposed a set of potential biomarkers for monitoring disease progression and predicting the risk of severity.