Development of a recombinant vaccine against foot and mouth disease utilizing mutant attenuated Listeria ivanovii strain as a live vector.

The drawbacks of conventional inactivated Foot and Mouth Disease (FMD) vaccine， such as escaping of the virus during manufacture processes prompted researchers to explore novel types of vaccine to overcome these disadvantages. Listeria ivanovii (LI) is an intracellular microorganism that possesses immune-stimulatory properties， making it appropriate for use as a live bacterial vaccine vector. The Foot and mouth disease virus (FMDV) VP1 protein is the most immunogenic part of FMDV capsid， it has most of the antigenic sites for viral neutralization. The expression of antigen gene cassette in vitro was confirmed by Western blot analysis. Mice were able to eliminate LI△actAplcB-vp1 from the liver and spleen within few days revealed a safety of the candidate vaccine. Two doses of LI△actAplcB-vp1 with 14 days of interval were injected into mice. High levels of specific IgG antibodies and CD8 and CD4 T cells secreted cytokines including IFN-γ， TNF-α and IL-2 against FMDV-VP1 were achieved. Based on the obtained results， LI△actAplcB-vp1 candidate vaccine utilizing Listeria ivanovii as a live vector-based vaccine could enhance a specific cellular and humoral immune responses against the inserted FMDV-vp1 heterologous genes. LI△actAplcB-vp1 candidate vaccine could be a modern tool to overcome the disadvantages of the traditional inactivated FMD vaccine.