Kunjin replicon-based simian immunodeficiency virusgagvaccines

An RNA-based, non-cytopathic replicon vector system, based on the flavivirus Kunjin, has shown considerable promise as a new vaccine delivery system. Here we describe the testing in mice of four different SIVmac239gagvaccines delivered by Kunjin replicon virus-like-particles. The four vaccines encoded the wild typegaggene, an RNA-optimisedgaggene, a codon-optimisedgaggene and a modifiedgag-polgene construct. The vaccines behaved quite differently for induction of effector memory and central memory responses, for mediation of protection, and with respect to insert stability, with the SIVgag-polvaccine providing the optimal performance. These results illustrate that for an RNA-based vector the RNA sequence of the antigen can have profound and unforeseen consequences on vaccine behaviour.