Engineered Viral Vectors: A New Era in Vaccine Delivery Strategies

Cancers and infectious diseases pose challenges to the stability of the global economy and the maintenance of public health. It is essential to develop novel preventative and therapeutic vaccines in order to improve public health and address these challenges. Among the many available vaccine platforms, the virus vector vaccine is the most popular, especially against pathogens that are challenging to control with conventional vaccines. Vaccines utilizing viral vectors effectively halted the spread of the SARS-CoV-2 virus and confronted the challenges posed by the COVID-19 pandemic. Recombinant DNA techniques have undergone significant development in recent years, enabling the pharmaceutical industry to modify viral vectors utilized for vaccine delivery. Through modifying cellular tropism, genetic stability, immunogenicity, resistance to existing immunity, and replication, genetically modified vectors have been developed with the aim of augmenting efficacy and safety. In addition, viral vectors enable large-scale production and reduce the dose required for administration. The capacity of engineered viral vectors to generate antigen proteins de novo within the cells is one of their primary advantages. This process not only stimulates antibody and T helper (Th) cell-mediated immunity but also triggers cytotoxic lymphocytes (CTL) responses, crucial for eliminating virus-infected cells. This feature holds particular promise for vaccines targeting specific viral infections and cancers. Many viruses including adenoviruses, adeno-associated viruses, vesicular stomatitis virus, lentiviruses, poxviruses, and herpesviruses have been genetically altered to deliver a vaccine to induce immune responses against the proteins produced by the expression of encoded transgenes. Furthermore, the advancement of engineered viral vector-based vaccines may improve vaccine efficacy and help us to manage future outbreaks.