Increasing cases of human infections with the high pathogenic avian influenza virus H5N1 have raised great concern on potential human flu pandemics caused by H5N1. The two viral surface glycoproteins, the hemagglutini...Increasing cases of human infections with the high pathogenic avian influenza virus H5N1 have raised great concern on potential human flu pandemics caused by H5N1. The two viral surface glycoproteins, the hemagglutinin (HA) and the neuraminidase (NA) proteins, are major antigens o H5N1. Introducing new mutations on these two pro teins is the major strategy used by H5N1 to expand host range and to avoid the recognition of host im mune systems. We analyzed the two surface proteins of H5N1 from Asian human patients and identified many new mutation sites, including a few that were unique to certain lethal strains. We also analyzed the distribution of mutations on different epitopes of the two surface proteins. A receptor-binding site tha might involve in the determination of host specificity of H5N1 was also found. Results reported here pro vided information for better understanding of the evolution trend of H5N1 genome in human.展开更多
A human hepatitis B virus (HBV) gene, which encodes the major surface antigen protein(S protein) carrying the hepatocyte receptor-binding site, was constructed with site-directed mutagenesis and in vitro recombination...A human hepatitis B virus (HBV) gene, which encodes the major surface antigen protein(S protein) carrying the hepatocyte receptor-binding site, was constructed with site-directed mutagenesis and in vitro recombination. When expressed in monkey kidney cell line COS-M6, this gene product (S309 protein) formed surface antigen (HBsAg) particles and secreted from the cells. It was stable within the cells and in the culture medium and could be immunoprecipitated with antisera directed against plasma-derived HBsAg or synthetic preS1 polypeptide. Isopycnic CsCl gradient centrifugation showed that the density of S309 protein particles (1.25 g/ml) was slightly higher than that of S protein particles. The S309 protein was readily secretable from hepatoma cell lines, and the amount secreted was comparable to that of the S protein. By contrast, only about 10% of the S309 protein was secreted from COS-M6 cells, and its appearance in culture medium was delayed. The efficiency of the secretion of the S309 protein can be improved when it is coexpressed with the S protein.展开更多
文摘Increasing cases of human infections with the high pathogenic avian influenza virus H5N1 have raised great concern on potential human flu pandemics caused by H5N1. The two viral surface glycoproteins, the hemagglutinin (HA) and the neuraminidase (NA) proteins, are major antigens o H5N1. Introducing new mutations on these two pro teins is the major strategy used by H5N1 to expand host range and to avoid the recognition of host im mune systems. We analyzed the two surface proteins of H5N1 from Asian human patients and identified many new mutation sites, including a few that were unique to certain lethal strains. We also analyzed the distribution of mutations on different epitopes of the two surface proteins. A receptor-binding site tha might involve in the determination of host specificity of H5N1 was also found. Results reported here pro vided information for better understanding of the evolution trend of H5N1 genome in human.
基金This research was supported in part by U.S.Public Health Service Grants CA-07175 and CA-22443 from the National Institutes of Health
文摘A human hepatitis B virus (HBV) gene, which encodes the major surface antigen protein(S protein) carrying the hepatocyte receptor-binding site, was constructed with site-directed mutagenesis and in vitro recombination. When expressed in monkey kidney cell line COS-M6, this gene product (S309 protein) formed surface antigen (HBsAg) particles and secreted from the cells. It was stable within the cells and in the culture medium and could be immunoprecipitated with antisera directed against plasma-derived HBsAg or synthetic preS1 polypeptide. Isopycnic CsCl gradient centrifugation showed that the density of S309 protein particles (1.25 g/ml) was slightly higher than that of S protein particles. The S309 protein was readily secretable from hepatoma cell lines, and the amount secreted was comparable to that of the S protein. By contrast, only about 10% of the S309 protein was secreted from COS-M6 cells, and its appearance in culture medium was delayed. The efficiency of the secretion of the S309 protein can be improved when it is coexpressed with the S protein.
