RECOMBINANT POXVIRUS HOST RANGE SELECTION SYSTEM

摘要

What is described is a modified recombinant virus for expressing a gene product in a host. The modified recombinant virus has host range genes deleted therefrom so that the virus has restricted replication in the host. The modified recombinant virus also contains DNA which codes for and expresses the gene product in the host even with restricted replication of the virus in the host. The modified recombinant virus is used in a method for expressing a gene product in a host or in a cell cultured in vitro, and in a vaccine for inducing an immunological response in a host inoculated with the vaccine. What is also described is a selection system for the cloning and expression of open reading frames in poxviruses, particularly vaccinia virus. The selection system is based on a conditional lethal mutant (host range) of poxviruses. A deletion/recombinant mutant of the vaccinia virus was generated which is capable of plaquing on primary chick embryo fibroblasts and two monkey cell lines (BSC-40 or VERO) but is defective in replication in the human cell line MRC-5. Insertion of the host range gene into the deletion/recombinant restores the ability for growth on MRC5 cells. A series of plasmids were constructed which allow for the rapid single-step cloning and expression of any open reading frame when recombined with the deletion/recombinant and scored for growth on MRC-5 cells.