AIM: Clinical therapy and prognosis in HCV infections are not good, and mix-infections with different HCV genotypes or quasispecies and mix-infections with HCV plus other hepatitis viruses are important concerns world...AIM: Clinical therapy and prognosis in HCV infections are not good, and mix-infections with different HCV genotypes or quasispecies and mix-infections with HCV plus other hepatitis viruses are important concerns worldwide. The present report describes the sequence diversity and genotying of the 5'NCR of HCV isolates from hepatitis patients mix-infected with different HCV genotypes or variants, and the conditions of mix-infections with HCV plus other hepatitis viruses, providing important diagnostic and prognostic information for more effective treatment of HCV infections.METHODS: The 5' non-coding region (5'NCR) of HCV was isolated from the patients sera and sequenced, and sequence variability and genotypes of HCV were defined by nucleotide sequence alignment and phylogenetic analysis, and the patients mix-infected with HCV plus other hepatitis viruses were analyzed. The conditions and clinical significance of mix-infections with HCV plus other hepatitis viruses were further studied.RESULTS: Twenty-four out of 43 patients with chronic hepatitis C were defined as mix-infected with different genotypes of HCV. Among these 24 patients, 9 were mixinfected with genotype 1 and 3, 7 with different variants of genotype 1, 2 with different variants of genotype 2, 6with different variants of genotype 3. No patients were found mix-infected with genotype 1 and 2 or with genotype 2 and 3. The clinical virological analysis of 60 patients mixinfected with HCV plus other hepatitis viruses showed that 45.0 % of the patients were mix-infected with HCV plus HAV, 61.7 % with HCV plus HBV, 6.7 % with HCV plus HDV/HBV, 8.4 % with HCV plus HEV, 3.3 % with HCV plus HGV. Infections with HCV plus other hepatitis viruses may exacerbate the pathological lesion of the liver.CONCLUSION: The findings in the present study imply that mix-infections with different HCV genotypes and mixinfections with HCV plus other hepatitis viruses were relatively high in Yunnan, China, providing important diagnostic and prognostic information for more effective treatment of HCV infections.展开更多
Objective To investigate the presentation of a neutralization epitope-containing peptide antigen of hepatitis E virus (HEV) on chimeric virus-like particles (VLPs) of hepatitis B surface antigen (HBsAg). MethodsThe ge...Objective To investigate the presentation of a neutralization epitope-containing peptide antigen of hepatitis E virus (HEV) on chimeric virus-like particles (VLPs) of hepatitis B surface antigen (HBsAg). MethodsThe gene fragment corresponding to amino acids (aa) 551-607 (HEnAg) of HEV capsid protein, which contains the only neutralization epitope identified to date, was fused via a synthetic glycine linker in frame with the gene of HBsAg. The resulted fusion gene was then integrated through transformation into the genome of Pichiapastorisunder the control of a methanol-induced alcohol oxidase 1 (AOX1) promoter and expressed intracellularly. The expression products in the soluble cell extracts were characterized by Western blot, ELISA, CsCl density gradient analysis, and electron microscopic visualiza-tion. Results The novel fusion protein incorporating HBsAg and the neutralization epitope-containing HEnAg was expressed successfully in Pichiapastoriswith an expected molecular weight of approximately 32 kD. It was found to possess the ability to assemble into chimeric HBV/HEV VLPs with immunological, physical and morphological characteristics akin to HBsAg particles. Not only did the chimeric VLPs show high activity levels in a HBsAg particle-specific ELISA but they were also strongly immunoreactive with hepatitis E (HE) positive human serum in a HEV specific ELISA, indicating that HEnAg peptide fragments were exposed on VLP surfaces and would be expected to be readily accessible by cells and molecules of the immune system. Similarity between chimeric VLPs to highly immunogenic HBsAg particles may confer good immuno-genicity on surface-displayed HEnAg. Conclusion The chimeric HBV/HEV VLPs produced in this study may have potential to be a recombinant HBV/HEV bivalent vaccine candidate.展开更多
AIM: To develop a novel process for production of HAV in Vero cells grown on microcarriers in a bioreactor.METHODS: Vero cells infected with HAV strain W were seeded at an initial density of 1×10^5 cells/mL into ...AIM: To develop a novel process for production of HAV in Vero cells grown on microcarriers in a bioreactor.METHODS: Vero cells infected with HAV strain W were seeded at an initial density of 1×10^5 cells/mL into a 7-L bioreactor containing Cytodex-I microcarriers. During the stage of cell proliferation, the following conditions were applied: pH 7.2±0.2, temperature 37±0.2℃, dissolved oxygen 40% of air saturation and agitation rate 40 r/min.After the stage of virus culture started, the culture conditions were altered to pH 7.2±0.2, temperature 35±0.2℃,dissolved oxygen 25% of air saturation, agitation rate 50 r/min and perfusion of fresh medium at a flux of 20 mL/h. During the course of fermentation, cell density, HAV antigen titre,glucose, lactate and ammonia levels were monitored. A control experiment using conventional static culture was conducted in the T150 flask.RESULTS: After a 28-d cultivation, cell density increased to 14.0×10^5 cells/mL in the bioreactor, 5.6×10^9 viable cells and 4 000 mL virus suspension with a titre of 1:64 were harvested.The viral antigen output per cell unit in the bioreactor was 3-fold higher than that in the T150 flask. Meanwhile the metabolic mode of Vero cells did not change after the infection with HAY strain W.CONCLUSION: The process for production of HAV in Vero cells grown on microcarriers in a bioreactor is a novel,efficient and practical way to obtain virus antigen for vaccine purpose. This approach produces more cells and HAV antigen than the conventional static culture. With futher improvement, it is possible to be used for the production of hepatitis A vaccine.展开更多
AIM: To construct and highly express an epitope of hepatitis C virus (HCV) in a foreign epitope presenting vectorbased on an insect virus, and to study the antigenicity of the epitope.METHODS: The HCV epitope sequence...AIM: To construct and highly express an epitope of hepatitis C virus (HCV) in a foreign epitope presenting vectorbased on an insect virus, and to study the antigenicity of the epitope.METHODS: The HCV epitope sequence (amino acidresidues 315 to 328: EGHRMAWDMMMNWS) of the E1 region was constructed at different positions of a foreign epitope presenting vector based on an insect virus, flock house virus (FHV) capsid protein encoding gene as a vector, and expressed in E. coli cells. Western blottingand ELISA were used to detect the immunoreactivity of these recombinant proteins.RESULTS: The gene encoding of the concerned B-cell epitope of HCV E1 envelope protein was expressed on FHV capsid carrier protein at positions I1 (aa 106), I2 (aa153) and I3 (aa 305), respectively, on the surface of FHV capsid protein. The recombinant proteins in this system could be highly expressed in more than 40% of total cell protein of E. coli BL21. All the expressed recombinant proteins were in inclusion body form, and showed obvious immunoreactivity by Western blotting. Further purified recombinant proteins were detected by indirect ELISA as coating antigen respectively. All recombinant proteins could still show immunoreactivity.CONCLUSION: The epitope of HCV E1 envelope protein can be highly expressed in FHV carrier system as a chimeric protein with high immunoreactivity. This system has multiple entry sites conferring many possible conformations closer to the native one for a given sequence.展开更多
The splicing of many alternative exons in the precursor messenger RNA (pre-mRNA) is regulated by extracellular factors but the underlying molecular bases remain unclear. Here we report the differential regulation of B...The splicing of many alternative exons in the precursor messenger RNA (pre-mRNA) is regulated by extracellular factors but the underlying molecular bases remain unclear. Here we report the differential regulation of Bcl-x pre-mRNA splicing by extracellular factors and their distinct requirements for pre-mRNA elements. In K562 leukemia cells, treatment with interleukin-6 (IL-6) or granulocyte-macrophage colony stimulating factor (GM-CSF) reduced the proportion of the Bcl-xL variant mRNA while treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) had no effect. In U251 glioma cells, however, TPA efficiently increased the Bcl-xL level. These regulations were also seen for a transfected splicing reporter mini-gene. Further analyses of deletion mutants indicate that nucleotides 1-176 of the downstream intron are required for the IL-6 effect, whereas additional nucleotides 177-284 are essential for the GM-CSF effect. As for the TPA effect, only nucleotides 1-76 are required in the downstream intron. Thus, IL-6, GM-CSF and TPA differentially regulate Bcl-x splicing and require specific intronic pre-mRNA sequences for their respective effects.展开更多
The connective tissue growth factor (CTGF) expression in cultured corneal fibroblasts and its effect on corneal fibroblasts proliferation in vitro were examined. Total RNA was extracted from early passaged rabbit corn...The connective tissue growth factor (CTGF) expression in cultured corneal fibroblasts and its effect on corneal fibroblasts proliferation in vitro were examined. Total RNA was extracted from early passaged rabbit corneal fibroblasts by guanidine isothiocyanate one-step method and mRNA was reversely transcripted into complementary DNA (cDNA). Specific CTGF primers were used in the PCR reaction and the products were analyzed by electrophoresis to determine the expression of mRNA for CTGF against DNA marker. House-keeping gene GAPDH was used as control. Different concentrations of CTGF (0.5, 5, 50, 500, 5 000, 50 000 ng/ml) were added into the third passaged corneal fibroblast culture system, and its effect on corneal fibroblast proliferation was measured by MTT method. The results showed that compared with a GAPDH 450 bp band, CTGF RT-PCR product showed a specific 120 bp band as expected. CTGF produced a dose-dependent increase in the proliferation of corneal fibroblasts but it inhibited fibroblast proliferation at higher concentrations (5 000 and 50 000 ng/ml). It was concluded that proliferating corneal fibroblasts produce CTGF and CTGF helps to promote corneal fibroblast proliferation. The results indicated that CTGF might be involved in the corneal wound healing after photorefractive keratectomy in which corneal fibroblasts are activated to proliferate and secrete growth factors that in turn promote corneal fibroblast proliferation.展开更多
基金the research grants from International Centre for Genetic Engineering and Biotechnology(ICGEB)Collaborative Research Program,CRP/CHN96-05from China Yunnan Provincial Science & Technology Commission International Collaborative Research Program,No.97C009
文摘AIM: Clinical therapy and prognosis in HCV infections are not good, and mix-infections with different HCV genotypes or quasispecies and mix-infections with HCV plus other hepatitis viruses are important concerns worldwide. The present report describes the sequence diversity and genotying of the 5'NCR of HCV isolates from hepatitis patients mix-infected with different HCV genotypes or variants, and the conditions of mix-infections with HCV plus other hepatitis viruses, providing important diagnostic and prognostic information for more effective treatment of HCV infections.METHODS: The 5' non-coding region (5'NCR) of HCV was isolated from the patients sera and sequenced, and sequence variability and genotypes of HCV were defined by nucleotide sequence alignment and phylogenetic analysis, and the patients mix-infected with HCV plus other hepatitis viruses were analyzed. The conditions and clinical significance of mix-infections with HCV plus other hepatitis viruses were further studied.RESULTS: Twenty-four out of 43 patients with chronic hepatitis C were defined as mix-infected with different genotypes of HCV. Among these 24 patients, 9 were mixinfected with genotype 1 and 3, 7 with different variants of genotype 1, 2 with different variants of genotype 2, 6with different variants of genotype 3. No patients were found mix-infected with genotype 1 and 2 or with genotype 2 and 3. The clinical virological analysis of 60 patients mixinfected with HCV plus other hepatitis viruses showed that 45.0 % of the patients were mix-infected with HCV plus HAV, 61.7 % with HCV plus HBV, 6.7 % with HCV plus HDV/HBV, 8.4 % with HCV plus HEV, 3.3 % with HCV plus HGV. Infections with HCV plus other hepatitis viruses may exacerbate the pathological lesion of the liver.CONCLUSION: The findings in the present study imply that mix-infections with different HCV genotypes and mixinfections with HCV plus other hepatitis viruses were relatively high in Yunnan, China, providing important diagnostic and prognostic information for more effective treatment of HCV infections.
文摘Objective To investigate the presentation of a neutralization epitope-containing peptide antigen of hepatitis E virus (HEV) on chimeric virus-like particles (VLPs) of hepatitis B surface antigen (HBsAg). MethodsThe gene fragment corresponding to amino acids (aa) 551-607 (HEnAg) of HEV capsid protein, which contains the only neutralization epitope identified to date, was fused via a synthetic glycine linker in frame with the gene of HBsAg. The resulted fusion gene was then integrated through transformation into the genome of Pichiapastorisunder the control of a methanol-induced alcohol oxidase 1 (AOX1) promoter and expressed intracellularly. The expression products in the soluble cell extracts were characterized by Western blot, ELISA, CsCl density gradient analysis, and electron microscopic visualiza-tion. Results The novel fusion protein incorporating HBsAg and the neutralization epitope-containing HEnAg was expressed successfully in Pichiapastoriswith an expected molecular weight of approximately 32 kD. It was found to possess the ability to assemble into chimeric HBV/HEV VLPs with immunological, physical and morphological characteristics akin to HBsAg particles. Not only did the chimeric VLPs show high activity levels in a HBsAg particle-specific ELISA but they were also strongly immunoreactive with hepatitis E (HE) positive human serum in a HEV specific ELISA, indicating that HEnAg peptide fragments were exposed on VLP surfaces and would be expected to be readily accessible by cells and molecules of the immune system. Similarity between chimeric VLPs to highly immunogenic HBsAg particles may confer good immuno-genicity on surface-displayed HEnAg. Conclusion The chimeric HBV/HEV VLPs produced in this study may have potential to be a recombinant HBV/HEV bivalent vaccine candidate.
基金Supported by the Natural Science Foundation of Yunnan Province,No.1999C0023Q
文摘AIM: To develop a novel process for production of HAV in Vero cells grown on microcarriers in a bioreactor.METHODS: Vero cells infected with HAV strain W were seeded at an initial density of 1×10^5 cells/mL into a 7-L bioreactor containing Cytodex-I microcarriers. During the stage of cell proliferation, the following conditions were applied: pH 7.2±0.2, temperature 37±0.2℃, dissolved oxygen 40% of air saturation and agitation rate 40 r/min.After the stage of virus culture started, the culture conditions were altered to pH 7.2±0.2, temperature 35±0.2℃,dissolved oxygen 25% of air saturation, agitation rate 50 r/min and perfusion of fresh medium at a flux of 20 mL/h. During the course of fermentation, cell density, HAV antigen titre,glucose, lactate and ammonia levels were monitored. A control experiment using conventional static culture was conducted in the T150 flask.RESULTS: After a 28-d cultivation, cell density increased to 14.0×10^5 cells/mL in the bioreactor, 5.6×10^9 viable cells and 4 000 mL virus suspension with a titre of 1:64 were harvested.The viral antigen output per cell unit in the bioreactor was 3-fold higher than that in the T150 flask. Meanwhile the metabolic mode of Vero cells did not change after the infection with HAY strain W.CONCLUSION: The process for production of HAV in Vero cells grown on microcarriers in a bioreactor is a novel,efficient and practical way to obtain virus antigen for vaccine purpose. This approach produces more cells and HAV antigen than the conventional static culture. With futher improvement, it is possible to be used for the production of hepatitis A vaccine.
基金Supported by the Natural Science Fund of Yunnan Province, No. 2003C0076M
文摘AIM: To construct and highly express an epitope of hepatitis C virus (HCV) in a foreign epitope presenting vectorbased on an insect virus, and to study the antigenicity of the epitope.METHODS: The HCV epitope sequence (amino acidresidues 315 to 328: EGHRMAWDMMMNWS) of the E1 region was constructed at different positions of a foreign epitope presenting vector based on an insect virus, flock house virus (FHV) capsid protein encoding gene as a vector, and expressed in E. coli cells. Western blottingand ELISA were used to detect the immunoreactivity of these recombinant proteins.RESULTS: The gene encoding of the concerned B-cell epitope of HCV E1 envelope protein was expressed on FHV capsid carrier protein at positions I1 (aa 106), I2 (aa153) and I3 (aa 305), respectively, on the surface of FHV capsid protein. The recombinant proteins in this system could be highly expressed in more than 40% of total cell protein of E. coli BL21. All the expressed recombinant proteins were in inclusion body form, and showed obvious immunoreactivity by Western blotting. Further purified recombinant proteins were detected by indirect ELISA as coating antigen respectively. All recombinant proteins could still show immunoreactivity.CONCLUSION: The epitope of HCV E1 envelope protein can be highly expressed in FHV carrier system as a chimeric protein with high immunoreactivity. This system has multiple entry sites conferring many possible conformations closer to the native one for a given sequence.
文摘The splicing of many alternative exons in the precursor messenger RNA (pre-mRNA) is regulated by extracellular factors but the underlying molecular bases remain unclear. Here we report the differential regulation of Bcl-x pre-mRNA splicing by extracellular factors and their distinct requirements for pre-mRNA elements. In K562 leukemia cells, treatment with interleukin-6 (IL-6) or granulocyte-macrophage colony stimulating factor (GM-CSF) reduced the proportion of the Bcl-xL variant mRNA while treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) had no effect. In U251 glioma cells, however, TPA efficiently increased the Bcl-xL level. These regulations were also seen for a transfected splicing reporter mini-gene. Further analyses of deletion mutants indicate that nucleotides 1-176 of the downstream intron are required for the IL-6 effect, whereas additional nucleotides 177-284 are essential for the GM-CSF effect. As for the TPA effect, only nucleotides 1-76 are required in the downstream intron. Thus, IL-6, GM-CSF and TPA differentially regulate Bcl-x splicing and require specific intronic pre-mRNA sequences for their respective effects.
文摘The connective tissue growth factor (CTGF) expression in cultured corneal fibroblasts and its effect on corneal fibroblasts proliferation in vitro were examined. Total RNA was extracted from early passaged rabbit corneal fibroblasts by guanidine isothiocyanate one-step method and mRNA was reversely transcripted into complementary DNA (cDNA). Specific CTGF primers were used in the PCR reaction and the products were analyzed by electrophoresis to determine the expression of mRNA for CTGF against DNA marker. House-keeping gene GAPDH was used as control. Different concentrations of CTGF (0.5, 5, 50, 500, 5 000, 50 000 ng/ml) were added into the third passaged corneal fibroblast culture system, and its effect on corneal fibroblast proliferation was measured by MTT method. The results showed that compared with a GAPDH 450 bp band, CTGF RT-PCR product showed a specific 120 bp band as expected. CTGF produced a dose-dependent increase in the proliferation of corneal fibroblasts but it inhibited fibroblast proliferation at higher concentrations (5 000 and 50 000 ng/ml). It was concluded that proliferating corneal fibroblasts produce CTGF and CTGF helps to promote corneal fibroblast proliferation. The results indicated that CTGF might be involved in the corneal wound healing after photorefractive keratectomy in which corneal fibroblasts are activated to proliferate and secrete growth factors that in turn promote corneal fibroblast proliferation.
