Identification of four linear B-cell epitopes on the SARS-CoV-2 spike protein able to elicit neutralizing antibodies

SARS-CoV-2 unprecedentedly threatens the public health at worldwide level. There is an urgent need to develop an effective vaccine within a highly accelerated time. Here, we present the most comprehensive S-protein-based linear B-cell epitope candidate list by combining epitopes predicted by eight widely-used immune-informatics methods with the epitopes curated from literature published between Feb 6, 2020 and July 10, 2020. We find four top prioritized linear B-cell epitopes in the hotspot regions of S protein can specifically bind with serum antibodies from horse, mouse, and monkey inoculated with different SARS-CoV-2 vaccine candidates or a patient recovering from COVID-19. The four linear B-cell epitopes can induce neutralizing antibodies against both pseudo and live SARS-CoV-2 virus in immunized wild-type BALB/c mice. This study suggests that the four linear B-cell epitopes are potentially important candidates for serological assay or vaccine development.

Recombinant Fc-fusion vaccine of RBD induced protection against SARS-CoV-2 in non-human primate and mice

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to infect people globally. The increased COVID-19 cases and no licensed vaccines highlight the need to develop safe and effective vaccines against SARS-CoV-2 infection. Multiple vaccines candidates are under pre-clinical or clinical trails with different strengths and weaknesses. Here we developed a pilot scale production of a recombinant subunit vaccine (RBD-Fc Vacc) with the Receptor Binding Domain of SARS-CoV-2 S protein fused with the Fc domain of human IgG1. RBD-Fc Vacc induced SARS-CoV-2 specific neutralizing antibodies in non-human primates and human ACE2 transgenic mice. The antibodies induced in macaca fascicularis neutralized three divergent SARS-CoV2 strains, suggesting a broader neutralizing ability. Three times immunizations protected Macaca fascicularis (20ug or 40ug per dose) and mice (10ug or 20ug per dose) from SARS-CoV-2 infection respectively. These data support clinical development of SARS-CoV-2 vaccines for humans. RBD-Fc Vacc is currently being assessed in randomized controlled phase 1/II human clinical trails. SummaryThis study confirms protective efficacy of a SARS-CoV-2 RBD-Fc subunit vaccine.

Rapid adaptation of SARS-CoV-2 in BALB/c mice: Novel mouse model for vaccine efficacy

Coronavirus disease 2019 (COVID-19) threatens global public health and economy. In order to develop safe and effective vaccines, suitable animal models must be established. Here we report the rapid adaption of SARS-CoV-2 in BALB/c mice, based on which a convenient, economical and effective animal model was developed. Specifically, we found that mouse-adapted SARS-CoV-2 at passage 6 (MACSp6) efficiently infected both aged and young wild-type BALB/c mice, resulting in moderate pneumonia as well as inflammatory responses. The elevated infectivity of MACSp6 in mice could be attributed to the substitution of a key residue (N501Y) in the receptorbinding domain (RBD). Using this novel animal model, we further evaluated the in vivo protective efficacy of an RBD-based SARS-CoV-2 subunit vaccine, which elicited highly potent neutralizing antibodies and conferred full protection against SARS-CoV-2 MACSp6 challenge. This novel mouse model is convenient and effective in evaluating the in vivo protective efficacy of SARS-CoV-2 vaccine. SummaryThis study describes a unique mouse model for SARS-CoV-2 infection and confirms protective efficacy of a SARS-CoV-2 RBD subunit vaccine.

Orthogonal test design for the optimization of superparamagnetic chitosan plasmid gelatin microspheres that promote vascularization of artificial bone.

The optimal conditions for the preparation of superparamagnetic chitosan plasmid (pReceiver-M29-VEGF165/DH5a) gelatin microspheres (SPCPGMs) were determined. Then, the performance of the SPCPGMs during neovascularization was evaluated in vivo. The SPCPGMs were prepared through a cross-linking curing method and then filled into the hollow scaffold of an artificial bone. Neovascularization at the bone defect position was histologically examined in samples collected 2, 4, 6, and 8 weeks after the operation. The cellular magnetofection rate of superparamagnetic chitosan nanoparticles/plasmid (pReceiver-M29-VEGF165/DH5a) complexes reached 1-3% under static magnetic field (SMF). Meanwhile, the optimal conditions for SPCPGM fabrication were 20% Fe3 O4 (w/v), 4 mg of plasmid, 5.3 mg of glutaraldehyde, and 500 rpm of emulsification rotate speed. Under oscillating magnetic fields (OMFs), 4-6 µg of plasmids was released daily for 21 days. Under the combined application of SMF and OMF, evident neovascularization occurred at the bone defect position 6 weeks after the operation. This result is expected to provide a new type of angiogenesis strategy for the research of bone tissue engineering.

Resonance light scattering spectroscopy can directly characterize protein solubility / 南方医科大学学报

OBJECTIVE@#To develop a fast, sensitive and cost-effective method based on resonance light scattering (RLS) for characterization of protein solubility to facilitate detection of changes in solubility of mutant proteins.@*METHODS@#We examined the response curve of RLS intensities to the protein concentrations in synchronous scanning mode. The curve intersection points were searched to predict the maximal concentrations of the protein in dispersion state, which defined the solubility of the protein in this given state. Bovine serum albumin (BSA, 0-50 g/L) was used as the model to investigate the influences of pH values (6.5, 7.0, and 7.4) and salt concentrations (0.05, 0.10, 0.15, and 0.20 mol/L) on the determined solubility. The solubility of glutathione S-transferase isoenzymes alpha (GSTA, 0-27.0 g/L) and Mμ (GSTM, 0-20.0 g/L) were estimated for comparison. The RLS-based method was used to determine the solubility of uricase (MGU, 0-0.4 g/L) to provide assistance in improving the solubility of its mutants.@*RESULTS@#We identified two intersection points in the RLS response curves of the tested proteins, among which the lower one represented an approximation of the maximal concentration (or the solubility of the protein) in single molecular dispersion, and the higher one the saturated concentration of the protein in multiple molecular aggregation. In HEPES buffer, the two intersection points of BSA (isoelectric point 4.6) both increased with the increase of pH (6.5-7.4), and their values were ~1.2 g/L and ~33 g/L at pH 7.4, respectively; the latter concentration approached the solubility of commercial BSA in the same buffer at the same pH. The addition of NaCl reduced the values of the two intersection points, and increasing salt ion concentration decreased the values of the lower intersection points. Further characterizations of GSTA and GSTM showed that the low concentration intersection points of the two proteins were ~0.7 g/L and ~0.8 g/L, and their high concentration intersection points were ~10 g/L and ~11 g/L, respectively, both lower than those of BSA, indicating the feasibility of the direct characterization of protein solubility by RLS. The two concentration intersection points of MGU were 0.24 g/L and 0.30 g/L, respectively, and the low concentration intersection point of its selected mutant was increased by 2 times.@*CONCLUSIONS@#RLS allows direct characterization of the solubility of macromolecular proteins. This method, which is simple and sensitive and needs only a small amount of proteins, has a unique advantage for rapid comparison of solubility of low-abundance protein mutants.

Oncolytic Activity of a Novel Influenza A Virus Carrying Granulocyte-Macrophage Colony-Stimulating Factor in Hepatocellular Carcinoma.

Oncolytic virotherapy is a promising strategy for the treatment of cancer. Influenza A virus has shown potential as an oncolytic agent. In this study, a recombinant PR8 influenza viral vector, called delNS1-GM-CSF, was generated with a partial deletion in NS and the granulocyte-macrophage colony-stimulating factor (GM-CSF) coding sequence inserted into the influenza nonstructural protein 1 gene. The morphological characteristics of delNS1-GM-CSF were examined. The delNS1-GM-CSF virus replicated well in various cell lines, including MDCK, A549, SMCC7721, and HepG2 cells. Moreover, selective cytotoxicity of the virus was observed in various hepatocellular carcinoma (HCC) cell lines, while no effect was demonstrated in the normal liver cell line LO2, as indicated by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide and crystal violet assays. Importantly, using a model based on the growth of HepG2 cells as a xenograft in nude mice, it was found that a reassortant delNS1-GM-CSF virus inhibited tumor growth significantly following intratumoral injection in a dose-dependent manner. Ex vivo results showed that the tumor inhibition efficacy of delNS1-GM-CSF was observed in HCC clinical samples. Taken together, these results are the first to demonstrate that influenza A viruses may have potential as oncolytic virotherapeutic agents against HCC.

Design and application of performance appraisal program at clinical departments based on the concept of value transfer / 中华医院管理杂志

Performance appraisal is one of the key points of hospital management. The authors introduce a comprehensive hospital performance appraisal scheme based on the concept of value transfer, including qualitative and quantitative index system, weight and appraisal method.In the pilot practice of a hospital, it is found that the appraisal scheme can effectively improve the operational efficiency, social and economic benefits, and has a strong incentive role for employees. This scheme weighs the operability and scientificity of performance appraisal, and provides a reference for clinical department performance appraisal.

Characterization of Mycobacterium tuberculosis dihydrofolate reductase immobilized on magnetic nanoparticles / 生物工程学报

To explore the immobilization of target proteins for screening libraries of ligand mixtures, magnetic submicron particles (MSP) functionalized with Ni²⁺-NTA and carboxyl were compared for the immobilization of Mycobacterium tuberculosis dihydrofolate reductase (MtDHFR). MtDHFR fused with 6×His was expressed, purified and characterized for kinetics. MtDHFR was immobilized on Ni²⁺-NTA-functionalized MSP directly and carboxyl-functionalized MSP upon activation. The immobilization capacity, residual activity, thermostability and affinities for putative inhibitors were characterized. MtDHFR immobilized on Ni²⁺-NTA-functionalized MSP retained about 32% activity of the free one with the immobilization capacity of (93±12) mg/g of MSP (n=3). Ni²⁺ and EDTA synergistically inhibited MtDHFR activity, while Fe³⁺ had no obvious interference. MtDHFR immobilized on carboxyl-functionalized MSP retained (87±4)% activity of the free one with the immobilization capacity of (8.6±0.6) mg/g MSP (n=3). In 100 mmol/L HEPES (pH 7.0) containing 50 mmol/L KCl, there was no significant loss of the activities of the free and immobilized MtDHFR after storage at 0 °C for 16 h, but nearly 60% and 35% loss of their activities after storage at 25 °C for 16 h, respectively. The inhibition effects of methotrexate on the immobilized and free MtDHFR were consistent (P>0.05). The immobilization of MtDHFR on carboxyl-functionalized MSP was thus favorable for higher retained activity and better thermostability, with promise for rapid screening of its ligand mixtures.

Prediction of maximum absorption activities with polyclonalantibodies immobilized on magnetic submicron particles torecognize positive mutants / 西安交通大学学报(医学版)

Objective To observe polyclonal antibodies immobilized on magnetic submicron particles (MSP) as affinity adsorbents and test the reliability of predicted maximum adsorption activity of an enzyme/mutant from a cell lysate (Vs) in recognizing positive mutants.Methods Escherichia coli alkaline phosphatase (ECAP) and Pseudomonas Aeruginosa arylsulfatase (PAAS) were purified by affinity chromatography to serve as immunogens for the preparation of their antisera, which after fractionation by 33％ ammonium sulfate and DEAE-cellulose chromatography yielded the respective polyclonal antibodies.After activation of COOH on MSP, polyclonal antibodies of each enzyme were immobilized to give MSP-polyAb.Activities of an adsorbed enzyme were measured with a chromogenic substrate of 4-nitrphenol by determining absorbance at 405nm after the termination of reaction by alkali.Based on the response curve of activities of the adsorbed enzyme to protein quantities of a lysate, Vs was predicted for comparison.Results The maximum adsorption quantity of ECAP or PAAS on the respective MSP-polyAb was about 2.0mg/g.Specific activity of ECAP after affinity purification was about 70-fold of that of PAAS.ECAP mutant R168K showing about 50％ activity improvement versus ECAP was recognized by comparison of Vs predicted with only 2.5μg of MSP-polyAb;with PAAS mutant G138S as the starting one, the use of 10.0μg of MSP-polyAb to predict Vs recognized the mutants bearing more than 20％ activity improvement.Conclusion With an optimized quantity of MSP-polyAb to predict Vs, weak positive mutants of an enzyme of low activity can be recognized when activities of the adsorbed enzyme/mutant are reliably measured.

Comparative study of indwelling gastric tube at different times in patients with invasive mechanical ventilation / 中国实用护理杂志

Objective Comparative study of gastric tube implantation at different times in patients with invasive mechanical ventilation. Methods Random sampling was used to divide 160 patients who were incubated with mechanical ventilation at the hospital into two groups,There were 80 patients in each group. Two groups of patients were routinely placed gastric tube by a stationary nurse.The observation group was treated with ordinary silica gel stomach tube at early stage(immediately)after trachea cannula, the control group still used the ordinary silica gel stomach tube after the trachea cannula late (24 hours later).The one-time successful rate,the total successful rate,the operation time and the result of the two Methods were observed in the two groups. Results The observation group Placing stomach tube one-time successful rate and the total successful rate was 75% (60/80), 97.5% (78/80), significantly higher than the control group 27.5%(22/80),72.5%(58/80),the difference was statistically significant(χ2=36.12, 19.61,P<0.01).The operation time of gastric tube in observation group was(1.49 ± 0.45)min,which was significantly lower than that of control group(3.07 ± 0.32)min,the difference was statistically significant (t=25.48,P<0.01).The observation group only heard gurgling not pumped to the gastric juice of 10 cases (12.50%), only smoke into the gastric juice does not hear the gurgling in 0 cases, both in 70 cases (87.50%),both in 0 cases,the control group were 37 cases(46.25%),0 cases,40 cases(50.00%),3 cases (3.75%). There were significant differences between the 2 groups in determining the success of gastric tube placement,and the difference was statistically significant(χ2=39.36,P<0.01). Conclusions After the trachea cannula,the ordinary silica gel gastric tube was placed in the early stage(immediately),which improved the successful rate of gastric tube placement in the mechanical ventilation patients, Shortened the operation time,improved the work efficiency and alleviated the patient's pain.

The cultivation of long-term-system medical undergraduates' innovative ability with the aid of extracurricular scientific and technological activities / 中华医学教育探索杂志

An auxiliary training system was explored for the development of creativity of long-termsystem medical undergraduates through scientific researches in spare time.In practice,professionals from research groups of different disciplines were recruited for developing wide-scope theoretical and technical bases of the undergraduates through training among these research groups followed by focused researches on topics of the running projects of these professionals.The undergraduates were engaged in a serial of research activities,including the discovery of problems for reasoning out scientific research projects,the writing of their project proposals,the summary of their data and the writing of reports,to develop their creativity and their qualification for scientific researches.

The clinical significance of troponin I and N-terminal pro-brain natriuretic peptide detection in the diagnosis of acute myocardial infarction / 国际检验医学杂志

Objective To investigate the clinical significance of troponin I and N-terminal pro-brain natriuretic peptide detection in the diagnosis of acute myocardial infarction(AMI).Methods The troponin I and N-terminal pro-brain natriuretic peptide(NT-proBNP)were detected in 89 AMI patients(AMI group)and in 102 non-AMI patients(non-AMI group).Results The troponin I and NT-proBNP levels in AMI group were significant higher than those in non-AMI group,and the difference was statistically sig-nificant(P <0.05).Meanwhile,the combined detection of troponin I and NT-proBNP could increase the sensitivity and specificity of AMI′s early diagnosis to 88.8% and 93.1%.Conclusion Early and rapid detection of troponin I and NT-proBNP could significant-ly improve the early diagnosis of acute myocardial infarction in sensitivity and specificity.

Expression and significance of signaling pathway of miR-134/CREB/pCREB in patients with epilepsy and in epileptic rats / 中国实验动物学报

Objective To investigate the expression of microRNA-134 ( miR-134 ) , CREB and pCREB in the temporal lobe tissue of patients and epileptic rats and to explore their roles in pathogenesis of epilepsy.Methods Tempo-ral lobe tissue samples of 14 patients with refractory epilepsy and 10 non-epileptic patients, and hippocampus and brain tis-sue samples of 42 rats were used in this study.Forty-two healthy adult male Sprague-Dawley rats were randomly divided in-to 6 epilepsy groups (24 h, 72 h, 7 d, 14 d, 30 d, and 60 d after kindling epilepsy) and a normal control group (n=6 for all groups) .The rat model of epilepsy was generated by intraperitoneal injection of 127 mg/kg lithium chloride and 16-20 h later, 35 mg/kg pilocarpine.In the temporal lobe tissue of patients and hippocampal tissue of rats, the expression level of miR-134 was detected by real-time polymerase chain reaction.The expression levels of CREB and pCREB were de-termined by Western blot, and CREB and pCREB localization was assessed by immunohistochemistry.Results Compared with the control rats, the expression of miR-134 was significantly decreased in the temporal lobe tissue of experimental rats at 72 h,7 d,14 d, 60 d after kindling (P＜0.05),and no significant change at 24 h and 30 d after kindling (P>0.05). Expression of miR-134 in patients with refractory epilepsy was significantly lower than that of the controls ( P＜0.05 ) , while up-regulation of CREB expression was at the same time points (P＜0.05).Up-regulation of pCREB expression was at all the time points after kindling (P＜0.05).CREB and p-CREB expressions were seen in the nuclei of neurons, and significantly higher in patients with refractory epilepsy and epileptic rats.Conclusions The expression of miR-134 is sig-nificantly decreased and that of CREB and pCREB was significantly increased in the temporal lobe tissue of patients with re-fractory epilepsy and the hippocampal tissue of epileptic rats.These findings indicate that the signaling pathway of miR-134/CREB/pCREB may play an important role in the pathogenesis of epilepsy.

Clinical Study on Infliximab for Treating Refractory Ulcerative Colitis / 胃肠病学

Background:Patients with refractory ulcerative colitis( UC ) cannot benefit from the conventional aminosalicylic acids,steroids and immunosuppressants. The emergence of biological agents offers new opportunities for these patients. Aims:To evaluate the clinical efficacy of infliximab for treating patients with refractory UC. Methods:Twelve patients with moderate to severe active UC admitted from Dec. 2012 to Jan. 2014 at the Second Affiliated Hospital of Harbin Medical University were retrospectively enrolled. All of them were steroids-refractory or steroids-dependent and infliximab therapy was then administered. Modified Mayo score was used to evaluate the disease activity and the efficacy of infliximab. Results:All patients completed the infliximab therapy and a 38-week follow-up. After treatment,the clinical manifestations were improved with varying degrees,and the efficacy at the 6th,22nd and 38th weeks was 66. 7%,83. 3% and 91. 7%, respectively,with significant differences between any two time points(P﹤0. 05). Conclusions:Infliximab is effective and practical for the treatment of refractory UC.

Discussion on the path of legal education / 中华医学教育探索杂志

The Socialist legal construction needs to strengthen the legal education.It is significant to seek for the path of legal education in order to enhance the actual effect of legal education.The path of legal cducation includes traditional education,utilitarian education,reasonable education,legitimate education and feeling education,etc.We can get a better actual effect of legal education if different paths of legal education (traditional education,utilitarian education,reasonable education,legitimate education and feeling education) can be integrated,infiltrated and complemented.

Effects of tetrazanbigen on the protein expression in human hepatocellular carcinoma cell line QGY-7701 / 华中科技大学学报（医学）（英德文版）

Tetrazanbigen (TNBG) is a novel synthetic antitumor drug with significant antitumor effects on common solid tumors in vitro and in vivo. It may lead to death of cancer cells through a tumor-associated lipoidosis mechanism, and result in lipid droplets (LDs) accumulation at the cytoplasm. In this study, the effects of TNBG on protein expression in human hepatocellular carcinoma cell line QGY-7701 were studied for elucidating its antitumor mechanism. The proteins extracted from TNBG-treated human hepatocellular carcinoma cell line QGY-7701 were analyzed and compared with control cells by two-dimensional gel electrophoresis. The differential proteins were identified by matrix-associated laser desorption ionization time-of-flight mass (MALDI-TOF-MS) spectrometry. Two proteins of interest, the levels of which were significantly increased in TNBG-treated cells, were further characterized by Western blot analysis. The results showed a total of 846+/-23 spots in control cells and 853+/-30 spots in TNBG-treated cells. Twenty-six up-regulated or down-regulated proteins were found by analyzing differential proteomic 2-DE map. Eleven of them were identified by mass spectrometry. They were protein disulfide-isomerase precursor, 94 kD glucose-regulated protein, heat shock protein (HSP) 90-alpha, ATP-citrate lyase, HMG-CoA reductase, glucose-6-phosphate 1-dehydrogenase, very-long-chain specific acyl-CoA dehydrogenase, squalene synthetase, sterol regulatory element-binding protein 1, fructose-bisphosphate aldolase A, and peroxiredoxin-1. These up-regulated or down-regulated proteins are mostly related to lipid metabolism. The TNBG antitumor mechanism is probably to influence tumor lipid metabolism, resulting in accumulation of LDs in tumor cells.

Hepatitis B Virus preS1-antigen HBV-DNA,and HBV Markers in Patients with Hepatitis B:Correlation Studies / 中华医院感染学杂志

OBJECTIVE To investigate the correlations on hepatitis B virus(HBV)preS1-antigen(preS1-Ag)and HBV-DNA,HBV markers in patients with hepatitis B.METHODS The markers,preS1-Ag and HBV-DNA were determined by ELISA and PCR in 406 patients with hepatitis B and 80 healthy persons.RESULTS The positive rates of preS1-Ag in 160 patients with HBsAg(+)and HBeAg(+)were 84.4%.The positive rates of preS1-Ag in 246 patients with HBsAg(+)and HBeAg(-)were 42.3%;the difference between them was significant(?2=70.9,P

Preparation and studies of the adsorbent double cross-linked agar beads entrapped attapulgite clay / 生物医学工程学杂志

A method for preparing the double cross-linked agar beads entrapped attapulgite clay for hemopurification is reported. Attapulgite clay was coated with agar and cross-linked by epichlorohydrin. After the process of "drying-out", the cross-linked agar beads entrapped attapulgite clay (CAA) was cross-linked again by 10% toluene 2,4,-diisocyanate in acetone at 35 degrees C for 3 h and 30 min. The products withstood autoclaving at 121 degrees C for 30 min. The performance tests showed that the adsorption of the double cross-linked agar beads entrapped attapulgite clay (DCAA) on methylene blue was about 4 times the adsorption of CAA on methylene blue. The intensity of DCAA was raised 6 times, and the appearance of DCAA was denser. Investigation on the blood being in contact with DCAA showed: at 1 h of contact, the loss of leucocyte was <1%, of erythrocyte <5%, and of blood platelets <8%; at 2h of contact, the loss of leucocyte was <2%, of erythrocyte <10%, and of blood platelets <20%.

Culturing of Urogenital Tract Mycoplasma and Its Susceptibility to Antibiotics:Analysis of 336 Cases in Zhoushan Islands / 中华医院感染学杂志

OBJECTIVE To explore the pathogenesis of Ureaplasma urealyticum(Uu)and Mycoplasma hominis(Mh)in urogenital tract infection and their susceptibility to antibiotics.METHODS Mycoplasma culture was carried out with the samples of 336 cases and then the susceptibility to 9 kinds of antibiotics was detected on positive samples.RESULTS From 336 cases 177 were infected with mycoplasma,the total positive rate was 52.7%,the positive rates of Uu,Mh and their mixed infection were 40.5%,2.4% and 9.8%,respectively.The positive rate of female was higher than of male(P

The Practice and Exploration of Teaching Reform on Medical Chemistry Experiment / 中华医学教育探索杂志

A series of reforms on the teaching of medical chemistry experiment has been carried out to arouse students' interest in medical chemistry experiment study and improve the quality of instruction,which includes the content of course,the teaching method and the inspection method.Good results have been achieved in the aspect of development of students' comprehensive quality,which lays a good foundation for the study of other courses.