Roles of vaccinia virus in the development of new vaccines.

Vaccinia virus is an efficient expression vector with broad host range infectivity and large DNA capacity. This vector has been particularly useful for identifying target antigens for humoral and cell-mediated immunity. With increased levels of gene expression, obtained either with stronger vaccinia promoters or through incorporation of the bacteriophage T7 RNA polymerase gene into the vaccinia genome, proteins may be synthesized in mammalian cells for use as subunit vaccines. For use as a live recombinant vaccine, efforts are being made to attenuate vaccinia virus further, either by inactivating genes contributing to virulence or by introducing human lymphokine genes into the vaccinia genome.