Method for generating nonpathogenic infectious pancreatic necrosis virus (IPNV) from synthetic RNA transcripts

A method for preparing nonpathogenic, infectious pancreatic necrosis virus, comprising the following steps:

• preparing a cDNA containing infectious pancreatic necrosis virus genome segments A and B, wherein the cDNA of segment A is modified to prevent the expression of NS protein,
• transcribing said cDNA to produce synthetic RNA transcripts,
• transfecting host cells with said synthetic RNA transcripts,
• incubating said host cells in a culture medium, and
• isolating live, nonpathogenic infectious pancreatic necrosis virus from said culture medium.

A method for producing a live, nonpathogenic, infectious pancreatic necrosis virus vaccine, comprising the steps of

• preparing a full-length cDNA containing infectious pancreatic necrosis virus genome segments A and B, wherein segment A has been modified to prevent expression of NS protein,
• transcribing said cDNA to produce synthetic RNA transcripts,
• transfecting host cells with said RNA transcripts,
• incubating said host cells in a culture medium,
• isolating live infectious, nonpathogenic pancreatic necrosis virus from said culture medium, and
• combining said live, nonpathogenic infectious pancreatic necrosis virus with a pharmaceutically acceptable carrier to produce a live, nonpathogenic, infectious pancreatic necrosis virus vaccine.

A method for generating a nonpathogenic, chimeric virus, comprising the following steps:

• preparing a cDNA containing infectious pancreatic necrosis virus genome segments A and B, wherein the cDNA of segment A is modified to prevent the expression of NS protein and said cDNA of segment A encodes epitopic determinants from at least two different infectious pancreatic necrosis virus strains,
• transcribing said cDNA to produce synthetic RNA transcripts,
• transfecting host cells with said synthetic RNA transcripts,
• incubating said host cells in a culture medium, and
• isolating live, nonpathogenic, chimeric, infectious pancreatic necrosis virus from said culture medium.

A live, nonpathogenic infectious pancreatic necrosis virus, wherein said infectious pancreatic necrosis virus strain is selected from the group consisting of West Buxton, Jasper and SP, and wherein said virus is made by a process comprising the steps of

• preparing a cDNA containing infectious pancreatic necrosis virus genome segments A and B, wherein segment A is modified to prevent the expression of NS protein,
• transcribing said cDNA to produce a synthetic RNA transcript,
• transfecting a host cell with said synthetic RNA transcript,
• incubating said host cell in a culture medium, and
• isolating live, nonpathogenic, infectious pancreatic necrosis virus from said culture medium.