What is the role of vaccinia virus in the development of recombinant vaccine?
Vaccinia virus serves as a vector in the development of recombinant vaccines. It is an enveloped virus belonging to the pox family with a large linear double stranded DNA genome containing around 200 genes. This large genome can accommodate stretches of foreign DNA, which can be expressed alongside its own genes.
With the help of rDNA technology, vaccinia virus carrying antigenic genes of several different pathogens can be constructed. These recombinant vaccinia viruses are capable of simultaneously providing protection against several different diseases. Such vaccines are known as polyvalent or multivalent vaccines based on their antigenic sites.
Explanation
The textbook context clearly explains that vaccinia virus acts as a vector-based vaccine carrier. Its key features include: (1) large genome size that can accommodate foreign DNA, (2) ability to express foreign antigenic genes alongside its own genes, and (3) capacity to carry multiple antigenic genes for protection against several diseases simultaneously. The context describes the process where antigen genes from pathogens like hepatitis virus, herpes simplex virus, and influenza virus are incorporated into the vaccinia virus genome through homologous recombination, generating recombinant vaccinia virus that offers elevated protection.