Future Viral Vectors For the Delivery of Asymptomatic Herpes Epitope-based Immunotherapeutic Vaccines

Abstract

The concept of using a recombinant virus to deliver viral antigens from a different virus for the purpose of therapeutic vaccination has been developed for more than 25 years [1]. In 1983, vaccinia virus recombinant for the hepatitis B surface antigen was the first viral vector to successfully induce protective immunity against HBV [1]. Since then, a number of viral vector-based vaccines, such as adenovirus, herpes simplex virus (HSV), vaccinia virus, retrovirus, Newcastle disease virus, vesicular stomatitis virus, measles virus, poliovirus and West Nile virus, have been designed and tested in both preclinical and clinical trials (reviewed in [2]). Genetically engineered HSV mutants have recently been exploited as promising vector platforms in immunotherapy (reviewed in [3]). Despite substantial development, the list of licensed viral-vector vaccines for human use remains short. The challenges include: issues concerning the large-scale production, the stability and the stringent safety requirements, especially for viral vectors that remain replicative or that persist in the host. Despite these challenges, the continued interest in developing viral-vector vaccines is due to their promising immunogenicity, especially for the most difficult antigens from notorious widespread pathogens, such as HSV-1 and/or -2.