Expression and Purification of Human Coagulation Factor X in Mammalian CHO-DG44 Cells

[Objectives]This study was conducted to obtain a Chinese hamster ovary cell line that stably expresses recombinant human coagulation factor X(rhFX),and to induce efficient expression of the target gene with different concentrations of methotrexate(MTX).[Methods]PCR was performed to obtain the rhFX gene,and a recombinant expression plasmid pOptiVEC-rhFX was constructed and subjected to double restriction endonuclease digestion and sequencing identification.CHO-DG44(DHFR-)cells were transfected by the liposome method,and the target protein was purified by affinity chromatography and detected by SDS-PAGE electrophoresis and Western blot.A cell line with efficient and stable expression of the target gene was obtained by increasing the concentration of MTX to select positive clones.[Results]PCR yielded a 1509 bp rhFX sequence,and the results of double digestion and sequencing showed that the constructed pOptiVEC-rhFX plasmid was correct.After transfection of cells,MTX significantly increased protein expression.When MTX reached 1.0μmol/L,the expression efficiency of the target protein was(9±0.27)μg/ml.The purity of the target protein purified by affinity chromatography was 93%,which could be used for subsequent experiments.The expression efficiency of rhFX in eukaryotic mammalian cells was improved by increasing MTX concentration,and an affinity chromatography purification process for the target protein was preliminarily established.[Conclusions]The results of this study provide data support for the expression and purification of rhFX,and will lay a solid foundation for the development of drugs related to rhFX.

Dynamic immune recovery process after liver transplantation revealed by single-cell multi-omics analysis

Elucidating the temporal process of immune remodeling under immunosuppressive treatment after liver transplantation(LT)is critical for precise clinical management strategies.Here,we performed a single-cell multi-omics analysis of peripheral blood mononuclear cells(PBMCs)collected from LT patients(with and without acute cellular rejection[ACR])at 13 time points.Validation was performed in two independent cohorts with additional LT patients and healthy controls.Our study revealed a four-phase recovery process after LT and delineated changes in immune cell composition,expression programs,and interactions along this process.The intensity of the immune response differs between the ACR and non-ACR patients.Notably,the newly identified inflamed NK cells,CD14+RNASE2+monocytes,and FOS-expressing monocytes emerged as predictive indicators of ACR.This study illuminates the longitudinal evolution of the immune cell landscape under tacrolimus-based immunosuppressive treatment during LT recovery,providing a four-phase framework that aids the clinical management of LT patients.

FedTop:a constraint-loosed federated learning aggregation method against poisoning attack

Federated learning(FL)is a decentralized machine learning paradigm,which has significant advantages in protecting data privacy[1].However,FL is vulnerable to poisoning attacks that malicious participants perform attacks by injecting dirty data or abnormal model parameters during the local model training and aim to manipulate the performance of the global model[2].

Surveillance on the Immune Effectiveness of Quadrivalent and Trivalent Split Influenza Vaccines—Shenzhen City and Changzhou City,China,2018–2019

Summary What is already known about this topic?Vaccinations are the most effective way to prevent influenza virus infections and severe outcomes.Influenza vaccine effectiveness can vary by seasons.What is added by this report?This report monitors the antibody level among the population over time after administration of the quadrivalent or trivalent split influenza vaccine.What are the implications for public health practice?Real-time monitoring of serum antibody changes after vaccination provides important data for the development of reasonable and effective strategies for influenza prevention and control.

Four COVID-19 Cases of New Variant B.1.351 First Emerging in South Africa in Chinese Passengers on Same Flight-Shenzhen,China,January 2021

At 04∶50 on January 1,2021,a 36-year-old Chinese project manager(Case A),a 29-year-old Chinese worker(Case B),and a 53-year-old Chinese businessman(Case C)returned from Africa(Case A and B from South Africa and Case C from Lesotho)on the same flight and tested coronavirus disease 2019(COVID-19)RNA positive by real-time polymerase chain reaction(PCR)by Baoan District People’s Hospital.Shenzhen CDC received their oral nasopharyngeal swabs packages from the hospital and retested COVID-19 RNA positive at 09∶50.Meanwhile,Case D.

Genome Characterization of COVID-19 Lineage B.1.1.7 Detected in the First Six Patients of a Cluster Outbreak——Shenzhen City,Guangdong Province,China,May 2021

Screening for coronavirus disease 2019(COVID-19)virus,also known as SARS-CoV-2,infection every seven days was performed for high-risk populations who worked at the Yantian Port in Yantian District,Shenzhen City,Guangdong Province.On May 20,2021,an oropharyngeal swab from a 44-year-old male(Case A)tested preliminarily positive for COVID-19 by a quantitative real-time reverse transcription polymerase chain reaction(RT-qPCR)method in a third-party laboratory.