Single chain MHC I trimer-based DNA vaccines for protection against Listeria monocytogenes infection

► We tested a MHC I/peptide single chain DNA vaccine against Listeria infection in mice. ► This approach was designed to optimize antigen presentation to CD8+ T cells. ► Kd/LLO single chain DNA vaccine elicited CD8+ T cells and reduced bacterial loads. ► Helper T cell responses improved memory but not primary anti-bacterial responses. ► Single chain approaches should be considered as part of a composite vaccine.