Vaccinia Virus Expression System

Abstract

Abstract Replication‐competent Vaccinia virus was used as the vaccine in the campaign to eradicate smallpox. After the disease was eradicated, recombinant Vaccinia viruses were created that were capable of expressing foreign genes. This made Vaccinia‐based systems available for mammalian cell expression of recombinant protein, an advantage of which, similar to other mammalian expression systems, is authentic posttranslational modification. Generation of recombinant Vaccinia also provided an opportunity for developing Vaccinia‐based vaccines for use against nonpoxvirus diseases. In this respect, recombinant Vaccinia virus and recombinant versions of an attenuated derivative, Modified Vaccinia virus Ankara (MVA) have been extensively studied. Today, there are recombinant Vaccinia viruses expressing foreign antigens in phases I–III clinical trials relating to viral, bacterial, parasitic and cancer‐related diseases, and a licensed veterinary vaccine. Key Concepts Smallpox was eradicated following a vaccination campaign in which live Vaccinia virus was used as the vaccine. Foreign genes can be inserted into the Vaccinia virus genome to create recombinant Vaccinia virus strains. The Vaccinia virus expression system allows for mammalian cell expression of recombinant protein, an advantage of which is authentic posttranslational modification. Recombinant Vaccinia can deliver vaccine antigens and evoke potent cell‐mediated and humoral responses specific to the inserted gene. Vaccination with recombinant organisms can confer protection against viral, bacterial, parasitic and cancer‐related diseases.