Mosaic infectious bursal disease virus vaccines
View Patent ↗The invention relates to Infectious Bursal Disease Virus (“IBDV”) and vaccines therefor. Provided are infectious recombinant Infectious Bursal Disease Virus (“rIBDV”) essentially incapable of growing in a cell that is not derived from a bursa cell, or an infectious rIBDV having retained at least part of the very virulent characteristics of a very virulent Infectious Bursal Disease Virus (“vvIBDV”).
1. A method for obtaining an infectious recombinant very virulent Infectious Bursal Disease Virus (vvIBDV), said method comprising:
transfecting at least one first cell, which cell is non-permissive for vvIBDV, with a recombinant nucleic acid comprising a vvIBDV genome;
incubating said at least one first cell in a culture medium, so as to produce recombinant vvIBDV which recombinant vvIBDV does not infect said at least one first cell, and which further retains its vvIBDV character;
rescuing said recombinant vvIBDV from said at least one transfected first cell or said culture medium; and
propagating said recovered rescued recombinant vvIBDV in at least one second cell which is permissive for said vvIBDV.
2. The method according to claim 1 wherein said at least one first cell is a non-bursa cell-derived cell.
3. The method according to claim 2 wherein said at least one second cell is a bursa cell-derived cell.
4. The method according to claim 2 wherein said at least one first cell is a CEF cell, a VERO cell or a QM5 cell.
5. The method according to claim 4 wherein said at least one first cell has additionally been provided with a helper virus or a viral protein derived from a helper virus.
6. The method according to claim 5 wherein said viral protein comprises T7-polymerase.
7. The method according to claim 6 wherein said vvIBDV has at least retained the incapacity to be propagated on a vvIBDV non-permissive cell selected from the group consisting of a VERO, a QM5 and a CEF cell.
8. The method according to claim 3 wherein said at least one second cell is a primary bursa cell.
9. The method according to claim 1 wherein said vvIBDV comprises a serotype II IBDV nucleic acid.
10. The method according to claim 9 wherein said vvIBDV is lacking at least one immunodominant epitope specific for a serotype I IBDV.
11. The method according to claim 1 wherein said at least one second cell is a bursa cell-derived cell.