The Polyepitope Approach to DNA Vaccination

The identification of the epitope as the smallest immunogenic subunit derived from antigenic proteins has promoted the development of epitope-based vaccines. These prevent the danger of administering whole proteins or genes that have unknown and possibly dangerous properties. Recent data suggest that DNA encoded epitopes in synthetic constructs can be processed and presented to CD8+ T-lymphocytes despite unnatural flanking amino acid sequences. This has allowed the development of polyepitope vaccines for cancer and infectious disease which induce multiple cytotoxic T-lymphocyte responses. The resultant immunity may be restricted to various HLA alleles and targeted to numerous antigens to avoid escape from immune detection by antigen loss variants. This review will describe the background of epitope and polyepitope-based vaccination strategies and the more recent results that confirm the potential of DNA encoded polyepitope vaccines. Future directions that may aid the design of more effective polyepitopes will also be discussed.