Strategies to enhance immunogenicity of cDNA vaccine encoded antigens by modulation of antigen processing.

Vaccine H56 antigen cDNA (1), fused to TTFC (tetanus toxin fragment C) or UB (ubiquitin) cDNA (2) and modified to flank CD8+ T cell epitope’ C-termini with a glutamic acid residue (3) was administered by tattoo immunization. Linkage to either TTFC or UB enhanced CD8+ T cell responses to all epitopes, while replacement of C-terminal epitope flanks for a Glu residue further increased the CD8+ T cell response to 4 out of 6 epitopes. These strategies can be exploited for vaccine design.