Systematic profiling of SARS-CoV-2 specific IgG epitopes at single amino acid resolution

SARS-CoV-2 specific IgG responses play critical roles for patients to recover from COVID-19, in-depth dissecting of the IgG responses on systems level is of great interest. Herein, we adopted a newly developed high-throughput epitope mapping technology (AbMap), analyzed 55 COVID-19 convalescent sera and 226 antibody samples enriched by specific proteins or peptides from these sera. We revealed three areas that are rich of IgG epitopes, two are on Spike protein but outside of RBD, and one is on Nucleocapsid protein. We identified 29 significant epitopes on Spike protein, from two of these significant epitopes, two critical epitope residues were found, i. e., D936 and P1263, which are highly related to the infectivity of SARS-CoV-2 In summary, we provided the first global map of IgG binding epitopes for SARS-CoV-2 at single amino acid resolution. This map will facilitate the precise development of therapeutic antibodies and vaccines. HIGHLIGHTSO_LIA map of SARS-CoV-2 specific IgG binding epitopes at single amino acid resolution C_LIO_LITwo areas outside of RBD that are rich of significant epitopes were identified C_LIO_LIOne area rich of significant epitopes was determined on Nucleocapsid protein C_LIO_LITwo critical epitope residues (D936 and P1263) on Spike protein are highly related to the infectivity of SARS-CoV-2 C_LI

Establishment of a Xenografted Acute Myeloid Leukemia Model by using Zebrafish / 中国实验血液学杂志

<p><b></b>Objectve: To investigate the feasibility of establishing xenografted leukemia model by zebrafish, so as to provide the more direct model in vitro and experimental evidence for study of acute myeloid leukemia and screening of the drugs for targeting therapy.</p><p><b>METHODS</b>Acute myeloid leukemia cell line KG-1a was labeled with red fluorescent dye-MitoRed, then the labeled cells were injected into the yolk sac of zebrafish embryos. Morphological observation, cell count and histopathological detection were used to analyse the infiltration and metastasis of KG-1a cells in zebrafish.</p><p><b>RESULTS</b>KG1a cells could proliferate and gradually spread to the entire abdominal cavity of the zebrafish after KG-1a cells were injected into the yolk sac during 1-7, the results of cell counting in vitro also proved a significant proliferation of KG-1a cells in zebrafish, suggesting that the implanted leukemia stem cells could survive, proliferate and spread in zebrafish. Further study showed that the implanted cells could be transfered to the liver of zebrafish, these cells displayed the signature of KG-1a cells by hematoxylin-eosin(HE) staining.</p><p><b>CONCLUSIONS</b>Human acute myeloid leukemia cells KG1a can survive, proliferate and migrate in zebrafish, suggesting xenografted leukemia model of zebrafish has been successfully established. This model may be benefitcial for the study of acute myeloid leukemia and the screening of the drugs for targeting therapy of acute myeloid leukemia.</p>