22 results on '"Xie, Qi‐Feng"'
Search Results
2. Author response for 'Geochemistry and zircon U-Pb ages of the Neoproterozoic Shimian plutons on the western margin of the Yangtze Block, Sichuan Province'
- Author
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null Xie, Qi-Feng, null Cai, Yuan-Feng, and null Zhai, Ming-Guo
- Published
- 2020
3. Thymosin α1 therapy in critically ill patients with COVID-19: A multicenter retrospective cohort study
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Wu, Ming, primary, Ji, Jing-jing, additional, Zhong, Li, additional, Shao, Zi-yun, additional, Xie, Qi-feng, additional, Liu, Zhe-ying, additional, Wang, Cong-lin, additional, Su, Lei, additional, Feng, Yong-wen, additional, Liu, Zhi-feng, additional, and Yao, Yong-ming, additional
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- 2020
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4. Geochemistry and zircon U–Pb ages of the Neoproterozoic Shimian plutons on the western margin of the Yangtze Block, Sichuan Province
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Xie, Qi‐Feng, primary, Cai, Yuan‐Feng, additional, and Zhai, Ming‐Guo, additional
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- 2020
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5. Simultaneous detection of two major lamivudine-resistant mutants using competitively differentiated-PCR
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Peng, Xiao Mou, Gu, Lin, Huang, Yang Su, Ma, Hui Hui, Xie, Qi Feng, Li, Gang, and Gao, Zhi Liang
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- 2005
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6. Interleukin-10 promoter polymorphisms are associated with the mode and sequel of HBeAg seroconversion in patients with chronic hepatitis B virus infection
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Peng, Xiao Mou, Huang, Yang Su, Ma, Hui Hui, Gu, Lin, Xie, Qi Feng, and Gao, Zhi Liang
- Published
- 2006
7. Geochemistry and zircon U–Pb ages of the Neoproterozoic Shimian plutons on the western margin of the Yangtze Block, Sichuan Province.
- Author
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Xie, Qi‐Feng, Cai, Yuan‐Feng, and Zhai, Ming‐Guo
- Subjects
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GEOCHEMISTRY , *ZIRCON , *IGNEOUS intrusions , *ISOTOPIC analysis , *LASER ablation inductively coupled plasma mass spectrometry , *PROVINCES - Abstract
The Shimian Neoproterozoic plutons are located on the western margin of the Yangtze Block and are important for reconstructing the tectonic environment of this region. We present in situ zircon LA–ICP–MS U–Pb geochronological and Hf isotopic analyses for the plutons, as well as whole‐rock major‐ and trace‐element compositions. The monzogranite and syenogranite yield concordant ages of 773.6 ± 5.6 Ma and 812.2 ± 1.8 Ma, respectively, which indicates that they formed during the Tonian of the Neoproterozoic. The samples have very similar geochemistry, with high SiO2 (71.45–75.46 wt%) and Al2O3 (12.38–14.36 wt%) contents. The samples have a geochemical characteristics typical of peraluminous A‐type granites, including high Ga/Al and Rb/Sr ratios and elevated contents of high‐field‐strength elements. The samples also display high Rb/Sr (13.9–23.0) and Rb/Nb (12.5–19.2) ratios. The monzogranite and syenogranite yield positive εHf(t) values (+1.6 to +9.4 and + 5.2 to +9.8, respectively) and T2DM ages of 1.54–1.22 Ga and 1.51–1.21 Ga, respectively, which indicates that they were derived from partial melting of Mesoproterozoic crust or contamination with upper mantle. We propose that the syenogranite and monzogranite formed in a syn‐orogenic extensional setting during the Tonian period and that continuous subduction was responsible for the Neoproterozoic magmatic activities. [ABSTRACT FROM AUTHOR]
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- 2021
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8. Decision of Cooperative Airfight and its Realization by Neural Network
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Feng Jinfu, Zhong Yong-bing, and Xie Qi-feng
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Artificial neural network ,Computer science ,business.industry ,Time delay neural network ,Decision theory ,Military computing ,Machine learning ,computer.software_genre ,Target distribution ,Set (abstract data type) ,Artificial intelligence ,business ,computer ,Realization (systems) - Abstract
For multi-target attacking decision, the airfight preponderant-function has been set up based on experience. Rules of target allotment in multi-target attack have been put forward, then the arithmetic of target assignment in multi-target attack is established, by which the decision of target distribution in cooperative multi-target attacking condition can been given. The artificial neural net was applied to the establishment of preponderant-function and target assignment arithmetic. Simulation experimentations have been made and the result shows that the construction of the ANN is correct.
- Published
- 2006
9. Optimal Deployment Model for near Space Bistatic Radar Network
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Wang, Shen Shen, primary, Che, Wan Fang, additional, Feng, Jin Fu, additional, Wang, Fang Nian, additional, and Xie, Qi Feng, additional
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- 2012
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10. Decision of Cooperative Airfight and its Realization by Neural Network.
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Xie Qi-feng, Feng Jin-fu, and Zhong Yong-bing
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- 2006
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11. Mohr Strength Theory in Simulation Stress Analysis
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Wang, Qiang, Li, Zhi Jun, Zhang, Jian Xue, Xie, Qi Feng, and Tang, Ping
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This paper describes the new method of the finite element analysis based on the product cycle design. Based on the simulation software, combined with the Mohr strength theory, analyze the cabinet in several classic conditions of stress, then have the final test on the cabinet in the consolidated operating conditions.
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- 2013
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12. Research on concept of conformal semi-ring wing configuration for water-air medium voyage.
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ZHANG Jia-qiang, FENG Jin-fu, XIE Qi feng, HU Jun-hua, and XU Hu
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AERODYNAMICS , *HYDRODYNAMICS , *ANGLE of attack (Aerodynamics) , *AIRPLANE wings , *WING-warping (Aerodynamics) - Abstract
To meet the mission requirement of alternately traversing water-air interface and freely voyaging either in air or water, solve the contradiction between aerodynamic configuration and hydrodynamic configuration, and endure huge water-entry impact, a conformal semi-ring wing configuration is proposed based on the extendable ring wing concept. Basic arrangement of single aero and hydro configuration is framed and the switch method is carried out by the wing's symmetrically rotating around aircraft axis. Aerodynamic and hydrodynamic performance of corresponding configuration is simulated by CFX under designed speed. Numerical simulation results indicate that, when the angle of attack (α) is 0° the lift and drag characteristic of aero configuration is twice as much as the plain wing configuration with the same airfoil, chord length and equivalent wing projective area, when α>12° the lift increasing ratio reduces to ten percent. The performance of hydro configuration is approximate to torpedo configuration, and when the aero configuration voyages in water, the wing drag accounts for 50% of the whole drag, while the wing lift proportion is settled to 50% as |α| > 15° When the absolute value of a is decreasing, lift ratio of the wing to aero configuration increases sharply, at α=3° the ratio reaches 98%. All the results validate the rationality and necessity of the two deployments and morphing scenario of conformal semi-ring wing configuration. [ABSTRACT FROM AUTHOR]
- Published
- 2012
13. [The comparative study on the regulation of apoptosis by hepatitis B virus X protein between B and C genotype].
- Author
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Ming Y, Xie QF, and Yang L
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- Antiviral Agents pharmacology, Cell Line, Cell Line, Tumor, Doxorubicin pharmacology, Hepatitis B drug therapy, Hepatitis B virology, Hepatitis B virus classification, Hepatitis B virus drug effects, Humans, Trans-Activators genetics, Viral Regulatory and Accessory Proteins, Apoptosis drug effects, Hepatitis B physiopathology, Hepatitis B virus genetics, Hepatitis B virus metabolism, Trans-Activators metabolism
- Abstract
Objective: To investigate the apoptosis regulation on hepatoma cells by HBx between genotype B and C., Methods: Genotype B and C HBx gene fragments were amplified and inserted into green fluorescent protein (GFP) eukaryotic expression vector pEGFP-C1 to construct recombinant pGFP-XB and pGFP-XC. The pEGFP-C1, pGFP-XB and pGFP-XC were introduced into Bel-7402 cells by Fugene HD to obtain Bel-7402 cells expressing GFP. The transcription and expression of HBx gene were demonstrated by RT-PCR and Western Blot analysis. Bel-7402, Bel-7402/GFP, Bel-7402/GFP-XB, Bel-7402/GFP-XC cells were treated with adriamycin (2.5 microg/ml), and the apoptosis of the cells was determined by trypan blue exclusion, and flow cytometry analysis., Results: RT-PCR and Western Blot analysis showed that HBx genes of genotypes B and C were transcribed and expressed in Bel-7402/GFP-XB, Bel-7402/GFP-XC cells. Trypan blue exclusion showed adriamycin induced time-dependent cell death in Bel-7402, Bel-7402/GFP cells while no significant cell death was observed in Bel-7402/GFP-XB, Bel-7402/GFP-XC cells. Flow cytometry analysis indicated that no significant differences of apoptosis rates of Bel-7402/GFP-XB (3.87%) and of Bel7402/GFP-XC (4.01%) were observed (P > 0.05), moreover, no significant differences of Bel-7402/ GFP-XB (3.87%), Be17402/GFP-XC (4.01%) and of the untreated cells. Apoptosis rates in Bel-7402/GFP-XB (3.87%), Bel-7402/GFP-XC (4.01%) cells were significantly lower than those in Bel-7402 (27.05%) and Bel-7402/GFP (29.14%) cells at 48 hours after the adriamycin treatment (P < 0.01)., Conclusions: Bel-7402 cell lines expressing GFP, GFP-XB and GFP-XC fusion proteins were successfully established. HBV X protein blocks adriamycin-induced apoptosis of Bel-7402 cells. There is no difference between HBx of genotype B and C in inhibiting apoptosis induced by adriamycin.
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- 2013
14. [Hepatitis B virus X promotes HepG2 cell cycle progression and growth via downregulation expression of p16 protein].
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Mai L, Yang L, Kuang JY, Zhu JY, Kang YH, Zhang FC, Xie QF, and Gao ZL
- Subjects
- Carcinoma, Hepatocellular metabolism, Cell Proliferation drug effects, Cyclin-Dependent Kinase Inhibitor p16 genetics, Gene Expression Regulation, Neoplastic, Genes, p16, Hep G2 Cells, Hepatitis B virus metabolism, Humans, Liver Neoplasms metabolism, Promoter Regions, Genetic, Viral Regulatory and Accessory Proteins, Carcinoma, Hepatocellular pathology, Cell Cycle drug effects, Cyclin-Dependent Kinase Inhibitor p16 metabolism, Liver Neoplasms pathology, Trans-Activators pharmacology
- Abstract
Objective: To investigate the effects and related mechanisms of hepatitis B virus X (HBx) protein on cell cycle and growth in hepatocellular carcinoma., Methods: A human hepatocyte HepG2 cell line stably expressing a green fluorescent protein (GFP)-tagged HBx (HepG2/GFP-HBx cells) was used for the experiment, and HepG2 parental and HepG2/GFP cells was used as the controls. Effect of HBx on cell growth was evaluated by the MTT cell proliferation assay and on cell cycle progression by flow cytometry analysis of cells with or without treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR; 5 pmol/L). Effect of HBx expression on promoter methylation status of the p16INK4A tumor-suppressor gene was detected by methylation-specific polymerase chain reaction and on p16 protein level was analyzed with western blotting., Results: The HepG2/GFP-HBx cells showed significantly higher cell proliferation at 72 hrs of culture (3.225+/-0.038 A490) than either control (HepG2: 2.012+/-0.022 A490, t = -46.86, P less than 0.001; HepG2/GFP: 2.038+/-0.029 A490, t = 42.51, P less than 0.001). The HepG2/GFP-HBx cells also showed significantly lower proportion of cells in the G0/G1 phase (16.45%+/-0.45%) than either control (HepG2: 44.81%+/-1.36%, t = -34.202, P less than 0.001; HepG2/GFP: 42.76%+/-1.58%, t = -28.88, P less than 0.001). However, 5-Aza-CdR treatment did lead to a significant amount of HepG2/GFP-HBx cells being arrested in the G0/G1 phase (33.25%+/-0.79%, t = 31.85, P less than 0.001). The p16INK4A promoter was methylated in the HepG2/GFP-HBx cells, and became demethylation after treatment with 5-Aza-CdR. However, no methylation of p16INK4A promoter was observed in both HepG2 and HepG2/GFP cells. The p16 protein level was significantly lower in the HepG2/GFP-HBx (vs. HepG2 and HepG2/GFP cells) and this level increased after treatment with 5-Aza-CdR., Conclusion: HBx protein promotes hepatocellular carcinoma cell cycle progression and growth by shortening the G0/G1 phase, and the underlying mechanism may involve inducing p16INK4A promoter methylation and downregulating p16 protein expression.
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- 2013
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15. [Small interfering RNA targeting to hepatitis B virus X gene and 5-aza-2'-deoxycytidineon inhibited growth of the subcutaneous implanted tumor of hepatocellular carcinoma in nude mice].
- Author
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Mai L, Yang L, Kuang JY, Zhang SQ, Kang YH, Xu QH, and Xie QF
- Subjects
- Animals, Azacitidine pharmacology, DNA Methylation, Decitabine, Genes, p16, Hep G2 Cells, Humans, Mice, Mice, Inbred BALB C, Mice, Nude, Neoplasm Transplantation, Trans-Activators genetics, Viral Regulatory and Accessory Proteins, Antimetabolites, Antineoplastic pharmacology, Azacitidine analogs & derivatives, Liver Neoplasms, Experimental therapy, RNA, Small Interfering, Trans-Activators antagonists & inhibitors
- Abstract
Objective: To investigate the anti-tumor effect of small interfering RNA targeting to HBV X gene (X-siRNA) and 5-aza-2'-deoxycytidine (5-aza-dC) on HBV-related hepatocellular carcinoma., Methods: X-siRNA and control siRNA were synthesized. HepG2/GFP-HBx cells were treated with X-siRNA, and the levels of HBV X mRNA were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Nude mice were inoculated with HepG2/GFP and HepG2/GFP-HBx cells subcutaneous respectively to establish implant models of hepatocellular carcinoma, and were treated with X-siRNA, 5-aza-dC alone or in combination, and tumor growth was observed. The methylation of p16 gene promoter was detected by methylation specific polymerase chain reaction (MSP)., Results: RT-PCR showed the expression of HBV X mRNA in HepG2/GFP-HBx cells was inhibited markedly by X-siRNA. The nude mice experiment showed that the gross tumor volume was much bigger in HepG2/GFP-HBx group than that in HepG2/GFP group (P < 0.05). The growth of palpable tumors in X-siRNA or 5-aza-dC treatment group notably decreased (P < 0.05). MSP analysis showed that p16 gene methylation was observed in HepG2/ GFP-HBx-caused palpable tumors, while no methylation was detected in HepG2/GFP group. However, after treatment with X-siRNA or 5-aza-dC, p16 gene methylation reduced., Conclusions: HBV X-siRNA and methylation inhibitor can inhibit the growth of hepatoma cells via reversing p16 methylation.
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- 2012
16. [Hepatitis B virus X protein suppresses adriamycin-induced apoptosis of hepatocellular carcinoma cells and expression of p53 and PTEN].
- Author
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Wang X, Yang L, She JJ, Fan HM, Zhang FC, Chen YM, and Xie QF
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- Apoptosis drug effects, Carcinoma, Hepatocellular pathology, Doxorubicin pharmacology, Hep G2 Cells, Humans, Liver Neoplasms pathology, Viral Regulatory and Accessory Proteins, Carcinoma, Hepatocellular metabolism, Liver Neoplasms metabolism, PTEN Phosphohydrolase metabolism, Trans-Activators metabolism, Tumor Suppressor Protein p53 metabolism
- Abstract
Objective: To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells and the expressions of p53 and PTEN., Methods: HepG2, HepG2/GFP, and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and the apoptotic cell death was determined by observing the morphological changes and flow cytometry. The expressions of p53 and PTEN mRNA in the 3 cells were detected by RT-PCR, and the expressions of p53 and PTEN protein were analyzed by Western blotting., Results: Adriamycin induced significant cell death in HepG2 and HepG2/GFP cells, which became rounded, shrunk, and detached after the treatment; but no significant cell death occurred in HepG2/GFP-HBx cells. Flow cytometry analysis showed that the apoptotic rate was significantly lower in HepG2/GFP-HBx cells (3.94%) than in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 h after the treatment (P<0.001), while no significant difference was observed between HepG2/GFP-HBx (3.94%) and the control cells (2.12%, 2.78%, and 2.55%) (P>0.05). RT-PCR showed lowered expression of PTEN mRNA in HepG2/GFP-HBx cells as compared to that in HepG2 and HepG2/GFP cells, while no significant difference was noted in p53 mRNA. Western blot analysis showed that PTEN protein decreased while p53 protein remain unchanged in HepG2/GFP-HBx cells., Conclusion: HBx suppresses adriamycin-induced apoptosis of HepG2 cells and PTEN expression. The inhibitory effect of HBx on the cell apoptosis may be related to the inhibition of p53-PTEN pathway.
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- 2010
17. [Efficacy of the 96-week adefovir dipivoxil therapy in patients with chronic hepatitis B].
- Author
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Xu Z, Chen LB, Cao H, Shu X, Xu QH, Li G, and Xie QF
- Subjects
- Adenine adverse effects, Adenine therapeutic use, Adolescent, Adult, Antiviral Agents adverse effects, Drug Resistance, Viral genetics, Female, Genotype, Hepatitis B e Antigens analysis, Hepatitis B virus drug effects, Hepatitis B virus immunology, Hepatitis B virus pathogenicity, Humans, Kidney Function Tests, Male, Middle Aged, Organophosphonates adverse effects, Young Adult, Adenine analogs & derivatives, Antiviral Agents therapeutic use, DNA, Viral analysis, Hepatitis B, Chronic drug therapy, Lamivudine therapeutic use, Organophosphonates therapeutic use, Renal Insufficiency etiology
- Abstract
Objective: To investigate the efficacy of the 96-week antiviral therapy with adefovir dipivoxil in patients with chronic hepatitis B., Methods: 80 patients with chronic hepatitis B received the antiviral therapy of adefovir dipivoxil (ADV, 10 mg/d). At the 12th week, 19 cases without early viral response (EVR, HBV DNA drop < 2 log10copies/ml) switched to the therapy of other nucleoside analogues. Aminotransferase (ALT) normalization, HBV DNA negative, HBeAg loss and HBeAg seroconvertion were accessed at the 96th week., Results: At week 96, ALT normalization and HBV DNA negative in 61 patients with ADV therapy were 85.25% (52/61) and 95.08% (58/61); and HBeAg loss and HBeAg seroconvertion were 52.52% (17/33) and 42.42% (14/33) respectively. While for the other 19 patients switching to other nucleoside analogues, ALT normalization and HBV DNA negative came to 57.89% (11/19) and 68.42% (13/19). Both HBeAg loss and HBeAg seroconvertion were 58.33% (7/12)., Conclusion: Long term ADV antiviral therapy is effective to inhibit HBV DNA replications and benefits patients with chronic hepatits B. Switching to another nucleoside analogue is an optimal alternative if there is no EVR at week 12 in ADV therapy.
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- 2010
18. [The relationship between the levels of HBV DNA loads and both the clinical characteristics and 48-week prognosis in patients with decompensated cirrhosis due to hepatitis B].
- Author
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Xu QH, Jie YS, Lin SZ, Shu X, Chen N, Xie QF, and Li G
- Subjects
- Adult, Aged, Female, Hepatitis B drug therapy, Hepatitis B virus genetics, Hepatitis B virus physiology, Humans, Liver Cirrhosis blood, Liver Cirrhosis drug therapy, Male, Middle Aged, Prognosis, Young Adult, DNA, Viral blood, Hepatitis B virology, Hepatitis B virus isolation & purification, Liver Cirrhosis diagnosis, Liver Cirrhosis virology, Viral Load
- Abstract
Objective: To evaluate the relationship between the levels of HBV DNA loads and both the clinical characteristics and 48-week prognosis in patients with decompensated cirrhosis due to hepatitis B., Methods: One hundred and forty-three patients with decompensated cirrhosis of hepatitis B virus infection were divided into low level HBV DNA group [HBV DNA < 10(5) copies/ml = (46 cases) and high-level HBV-DNA group (HBV DNA > or = 10(5) copies/ml) (97 cases)]. 21 cases in low-level group and 52 cases in high-level group treated with nucleoside analog., Results: There was no significant difference between the two groups on the demography and the baseline in ALT, ALB, TBil, CHE before treatment, while in AST and HBeAg were statistically different. At 48-week, there was no significant difference between the two groups on the liver function. The mortality rate in low-level group was similar to that in high level group. In the low-level HBV DNA patients, hepatocellular carcinoma, spontaneous peritonitis and gastrointestinal hemorrhage were higer than that in the high-level HBV DNA patients., Conclusion: In patients with decompensated cirrhosis due to hepatitis B, those who were in low-level HBV DNA had not got better than that in high-level HBV DNA, which indicated that earlier treatment was also needed in low-level HBV DNA patients.
- Published
- 2009
19. [The antiviral treatment impacts on clinical outcomes of renal transplantation recipients with hepatitis B virus infection].
- Author
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Wei ZW, Xu QH, Shu X, Jie YS, Zhang K, Xie QF, and Li G
- Subjects
- Adenine analogs & derivatives, Adenine therapeutic use, Adult, Aged, Case-Control Studies, Female, Hepatitis B virology, Hepatitis B virus drug effects, Humans, Lamivudine therapeutic use, Male, Middle Aged, Organophosphonates therapeutic use, Treatment Outcome, Antiviral Agents therapeutic use, Hepatitis B drug therapy, Hepatitis B virus physiology, Kidney Transplantation mortality
- Abstract
Unlabelled: OBJECTIVE; To investigate the clinic outcomes and the efficacy of antiviral treatment in renal transplantation recipients with hepatitis B viral serum markers positive., Methods: 32 renal transplantation recipients with hepatitis B viral serum markers positive were enrolled. 23 patients in antiviral treatment group have received the lamivudine (19 cases), enticavir (2 cases) and adefovir (1 case). Another 9 patients have not received the antiviral treatment and were as the control group., Results: The biochemical response rate in antiviral treatment group and control group is 82.60% and 22.22%, respectively. 19 of 23 (82.60%) patients in treatment group survived and 1 of 9 (11.11%) patients in control group survived (P < 0.05). 20 of 23 (86.95%) patients in treatment group have the reduction of HBV DNA more than 2 log copies/ml or maintain less than 5 log copies/ml, while 1 of 9 (11.11%) patients in control group has the HBV DNA maintain less than 5 log copies/ml (P < 0.05). The virology rebound was observed in 6 of 19 (31.58%) patients with lamivudine treatment. 2 of them shift to enticavir treatment and 1 of them add adefovir treatment. The three patients survived. Other 3 patients die of liver function failure., Conclusion: The antiviral could improve the survival in renal transplantation recipients with hepatitis B viral serum markers positive. When the virology rebound occurs, the add-on with adefovir or the shift to enticavir could be a rescue treatment.
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- 2009
20. [Hepatitis B virus X protein suppressing adriamycin-induced apoptosis of HepG2 cells].
- Author
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Fan HM, Yang L, Xie QF, Han XY, Wu M, Zhang FC, Yao CL, Li G, and Gao ZL
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- Hep G2 Cells, Humans, Plasmids, Viral Regulatory and Accessory Proteins, Apoptosis drug effects, Doxorubicin pharmacology, Trans-Activators genetics
- Abstract
Objectives: To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells., Methods: HBx gene fragment was amplified from subtype adr HBV plasmid by PCR, and inserted into Hind III and Kpn I sites of green fluorescent protein (GFP) eukaryotic expression vector pEGFP-C1 to construct recombinant pGFP/HBx. The pEGFP-C1 and pGFP-HBx were introduced into HepG2 cells by Lipofectamine 2000 to obtain HepG2 cells expressing GFP. GFP-HBx fusion protein was selected using G418. The expression of HBx gene was demonstrated by RT-PCR analysis. HepG2, HepG2/GFP and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and apoptosis of the cells was determined by their morphological changes, trypan blue exclusion, and flow cytometry analysis., Results: Under a fluorescence microscope, visible expression of GFP and GFP-HBx fusion proteins were observed in HepG2/GFP and HepG2/GFP-HBx cells, even after growing over 70 generations. RT-PCR analysis showed that HBx gene was expressed in HepG2/GFP-HBx cells. Trypan blue exclusion showed adriamycin induced time-dependent cell death in HepG2 and HepG2/GFP cells while no significant cell death was observed in HepG2/GFP-HBx cells. Flow cytometry analysis showed that apoptosis rates in HepG2/GFP-HBx (3.94%) cells were significantly lower than those in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 hours after the adriamycin treatment (P < 0.01). No significant differences of apoptosis rates of HepG2/GFP-HBx (3.94%) and of the untreated cells (2.12%, 2.78%, 2.55%) (P > 0.05) were observed., Conclusion: A HepG2 cell line expressing GFP and GFP-HBx fusion proteins was successfully established. HBV X protein blocks adriamycin-induced apoptosis of these HepG2 cells.
- Published
- 2008
21. Yeast expression and DNA immunization of hepatitis B virus S gene with second-loop deletion of alpha determinant region.
- Author
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Hu H, Peng XM, Huang YS, Gu L, Xie QF, and Gao ZL
- Subjects
- Animals, Epitopes, Female, Gene Expression Regulation, Fungal, Hepatitis B immunology, Hepatitis B virology, Immunization, Mice, Polymorphism, Restriction Fragment Length, Recombinant Proteins immunology, Vaccines, DNA, Hepatitis B genetics, Hepatitis B Surface Antigens genetics, Recombinant Proteins genetics, Sequence Deletion, Yeasts genetics
- Abstract
Aim: Immune escape mutations of HBV often occur in the dominant epitope, the second-loop of the a determinant of hepatitis B surface antigen (HBsAg). To let the hosts respond to the subdominant epitopes in HBsAg may be an effective way to decrease the prevalence of immune escape mutants. For this reason, a man-made clone of HBV S gene with the second-loop deletion was constructed. Its antigenicity was evaluated by yeast expression analysis and DNA immunization in mice., Methods: HBV S gene with deleted second-loop, amino acids from 139 to 145, was generated using splicing by overlap extension. HBV deleted S gene was then cloned into the yeast expression vector pPIC9 and the mammalian expression vector pcDNA3 to generate pHB-SDY and pHB-SD, respectively. The complete S gene was cloned into the same vectors as controls. The deleted recombinant HBsAg expressed in yeasts was detected using Abbott IMx HBsAg test kits, enzyme-linked immunoadsorbent assay (ELISA) and immune dot blotting to evaluate its antigenicity in vitro. The anti-HBs responses to DNA immunization in BALB/c mice were detected using Abbott IMx AUSAB test kits to evaluate the antigenicity of that recombinant protein in vivo., Results: Both deleted and complete HBsAg were successfully expressed in yeasts. They were intracellular expressions. The deleted HBsAg could not be detected by ELISA, in which the monoclonal anti-HBs against the alpha determinant was used, but could be detected by Abbott IMx and immune dot blotting, in which multiple monoclonal anti-HBs and polyclonal anti-HBs were used, respectively. The activity of the deleted HBsAg detected by Abbott IMx was much lower than that of complete HBsAg (the ratio of sample value/cut off value, 106+/-26.7 vs 1 814.4+/-776.3, P<0.01, t = 5.02). The anti-HBs response of pHB-SD to DNA immunization was lower than that of complete HBV S gene vector pHB (the positive rate 2/10 vs 6/10, 4.56+/-3.52 mIU/mL vs 27.60+/-17.3 mIU/mL, P = 0.02, t = 2.7)., Conclusions: HBsAg with deleted second-loop of the alpha determinant still has antigenicity, and can also raise weak anti-HBs response in mice to DNA immunization, suggesting that it is possible to develop a subdominant vaccine for preventing infections of immune escape mutants of HBV.
- Published
- 2004
- Full Text
- View/download PDF
22. Construction of exogenous multiple epitopes of helper T lymphocytes and DNA immunization of its chimeric plasmid with HBV pre-S2/S gene.
- Author
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Gao WJ, Peng XM, Xie DY, Xie QF, Gao ZL, and Yao JL
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Epitopes, Female, Hepatitis B Surface Antigens immunology, Immunization, Mice, Mice, Inbred BALB C, Molecular Sequence Data, Polymorphism, Restriction Fragment Length, Recombinant Fusion Proteins immunology, Hepatitis B Surface Antigens genetics, Plasmids genetics, Recombinant Fusion Proteins genetics, T-Lymphocytes, Helper-Inducer immunology, Vaccines, DNA immunology
- Abstract
Aim: To design and construct an exogenous multiple epitope of helper T lymphocytes (HTL), and to evaluate its effect on anti-HBs response through DNA immunization., Methods: Artificial HTL epitope, PADRE and four other HTL epitopes from different proteins were linked together using splicing by overlap extension to generate exogenous multiple epitopes of HTL, MTE5. pcMTE5 and pcHB were generated by cloning MTE5 and fragments of HBV pre-S2/S gene into mammalian expression plasmid pcDNA3. Four chimeric plasmids were constructed by cloning MTE5 into the region of pre-S2 gene (Bam HI), 5' terminal of S gene (HincII, Xba I) and 3' terminal of S gene (Acc I) of pcHB respectively. BALB/c mice were used in DNA immunization of the recombinant plasmids. Anti-HBs was detected using Abbott IMx AUSAB test kits., Results: The sequences of MTE5 and the 6 constructs of recombinant plasmids were confirmed to be correct by DNA sequencing. The anti-HBs response of the co-inoculation of pcHB and pcMTE5 was much higher than that of the inoculation of pcHB only (136.7+/-69.1 mIU/mL vs 27.6+/-17.3 mIU/mL, P<0.01, t = -6.56). Among the 4 chimeric plasmids, only the plasmid in which MTE5 was inserted into the pre-S2 region had good anti-HBs response (57.54+/-7.68 mIU/mL), and had no significant difference compared with those of pcHB and the co-inoculation of pcHB and pcMTE5., Conclusion: Exogenous multiple epitopes of HTL had immune enhancement when they were co-inoculated with pre-S2/S gene or inoculated in the chimeric form at a proper site of pre-S2/S gene of HBV. It might suggest that it was possible to improve hepatitis B vaccine using exogenous multiple epitopes of HTL. The antibody responses were very low using DNA immunization in the study. Thus, the immune enhancement effect of exogenous multiple epitopes of HTL has to be confirmed and the effect on overcoming the drawback of the polymorphism of HLA II antigens should also be evaluated after these chimeric plasmids are expressed in mammalian cell lines.
- Published
- 2004
- Full Text
- View/download PDF
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