Immunogenicity of newly constructed attenuated vaccinia strain LC16m8Δ that expresses SIV Gag protein

We developed the method to efficiently construct recombinant vaccinia viruses based on LC16m8Δ strain that can replicate in mammalian cells but is still safe in human. Immunization in a prime-boost strategy using DNA and LC16m8Δ expressing SIV Gag elicited 7-30-fold more IFN-γ-producing T cells in mice than that using DNA and non-replicating vaccinia DIs recombinant strain. As the previous study on the DNA-prime and recombinant DIs-boost anti-SIV vaccine showed protective efficacy in the macaque model [Someya K, Ami Y, Nakasone T, Izumi Y, Matsuo K, Horibata S, et al. Induction of positive cellular and humoral responses by a prime-boost vaccine encoded with simian immunodeficiency virus gag/pol. J Immunol 2006;176(3):1784-95], LC16m8Δ would have potential as a better recombinant viral vector for HIV vaccine.