Vaccinia virus: a novel approach for molecular engineering of peptide vaccines.

One of the more promising new approaches for producing prophylactic vaccines involves the genetic engineering of vaccinia virus (VV) strains to express a single protein, a portion of a protein, or a single epitope from a heterologous pathogen. As an example, the application of this approach to the prevention of streptococcal-related diseases is considered. Experiments are described in which several generations of VV-based recombinant vaccines were constructed that expressed various derivatives of the M protein gene from Streptococcus pyogenes (serotype 6). These recombinants were used to demonstrate the high-level expression, stability, and antigen authenticity of the bacterial proteins expressed in infected tissue culture cells. When tested in a mouse model system, immunization with the VV recombinants expressing specific subdomains of the M protein conferred protection to challenge from both homologous and heterologous serotypes of pathogenic streptococci.