Immunogenicity of a plant-derived edible rotavirus subunit vaccine transformed over fifty generations

Major efforts have been put forth for the development of effective rotavirus vaccines including transgenic plant vaccines. Previous studies have reported that rotavirus VP7 maintains its neutralizing immunity when it is transformed into the potato genome. The present study was aimed at investigating the hereditary stability of VP7-transformed potatoes over fifty generations. The VP7 gene was stably transcribed and expressed in potato cells as detected by RT-PCR and Western blotting. Humeral and mucosal responses were successfully induced in BALB/c mice fed with the fiftieth generation transformed potato tubers. There were no significant differences in serum IgG and fecal IgA between the mice fed with the first and fiftieth generation potatoes (P > 0.05). Profiles of cytokines such as IFN-gamma, IL-2, IL-4, IL-5 and TGF-beta in immunized mice showed a naive T-cells bias to Th1 and Th3 polarization. Moreover, specific CTL responses were also detected in C57BL/6 mice fed with transformed potatoes. This research represents a significant step towards the development of rotavirus vaccines derived from a transgenic plant that can be obtained by long-term and large-scale vegetative reproduction. To our knowledge, this is the first finding regarding vaccines derived from plants that can be propagated for many generations.