Dendritic Cell Targets for Self-Replicating RNA Vaccines

Vaccination is the cornerstone for controlling many pathogen infections [1-8], and is also under scrutiny for cancer Immunoprophylaxis/immunotherapy [9,10]. Induction of both antibody and cell-mediated immune (CMI) defences is preferable for ensuring robust immune defence against most pathogen infections, although defence against certain pathogens may require a more dominant CMI response as exemplified by hepatitis C virus [11]. A major drawback of most current vaccines is their non-replicative nature [3,8], being inactivated or recombinant protein-based vaccines, limiting the amount of antigen available to the immune system. Replicating vaccines offer several rounds of antigen production to increase the efficacy of immune defence induction [3,8]. This replicative nature can mimic the situation with replicating pathogens, whereby antigen can be directed into both MHC Class I and MHC Class II presentation pathways, thus promoting humoral and CMI defences. These characteristics are also important for cancer vaccines, particularly when the immunogen in question is weak.