We have developed a transencapsidated vaccine delivery system based on the insect virus, Flock House virus (FHV). FHV is attractive due to its small genome size, simple organization, and non-pathogenic characteristics. With the insertion of a Tobacco mosaic virus (TMV) origin of assembly (Oa), the independently replicating FHV RNA1 can be transencapsidated by TMV coat protein. In this study we demonstrated that the Oa adapted FHV RNA1 transencapsidation process can take place in planta, by using a bipartite plant expression vector system, where TMV coat protein is expressed by another plant virus vector, Foxtail mosaic virus (FoMV). Dual infection in the same cell by both FHV and FoMV was observed. Though an apparent classical coat protein-mediated resistance repressed FHV expression, this was overcome by delaying inoculation of the TMV coat protein vector by three days after FHV vector inoculation. Expression of transgene marker in animals by these in vivo generated transencapsidated nanoparticles was confirmed by mouse vaccination, which also showed an improved vaccine response compared to similar in vitro produced vaccines.
Zhou, Y., Maharaj, P., Mallajosyula, J., McCormick, A., & Kearney, C. (2015). In planta production of flock house virus transencapsidated RNA and its potential use as a vaccine. Molecular Biotechnology, 57(4), 325-336.
Originally published in Molecular Biotechnology, 57(4), 325-336. This is an accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12033-014-9826-1.