| 摘要 |
<p>Double-stranded cDNA was synthesized from nucleic acid extracted from Norwalk virus purified from stool specimens of volunteers. Single-stranded RNA probes derived from the DNA clone after subcloning into an in vitro transcription vector were also used to show that the Norwalk virus contains an ssRNA genome of about 8 kb in size. The availability of a Norwalk-specific cDNA and the genome sequence information allow rapid cloning of the entire genome and establishment of sensitive diagnostic assays. Such assays can be based on detection of Norwalk and Norwalk-related virus nucleic acids or Norwalk and Norwalk-related viral antigens using probes or primers and polyclonal or monoclonal antibodies to proteins expressed from the cDNA or to synthetic peptides made based on the knowledge of the genome sequence. Assays using proteins deduced from the Norwalk virus genome and produced in expression systems can measure antibody responses. Vaccines for Norwalk and related viruses are made from an expressed Norwalk virus protein.</p> |
