Edible vaccines: Immunological response to hepatitis B virus nucleocapsid derived from transgenic plants

The Hepatitis B virus (HBV) nucleocapsid self-assembles into virus-like particles and can be exploited for the presentation of various foreign B- and T-cell epitopes for HBV and non-HBV vaccine design. A construct containing a codon-optimized truncated HBV nucleocapsid gene (HBc153) was expressed in tobacco, carrots, and rice. Recombinant HBc153 was also expressed in E. coli and insect cells via the Bac-to-Bac Baculovirus expression system to serve as a control. The immunogenicity of HBc153 from transgenic plants was assessed in BALB/c mice using different routes of immunization, including feeding and subcutaneous immunization. The E. coli recombinant HBc153 was also delivered by oral gavage and intranasally. In order to characterize the immune response the serum total IgG, as well as the prevalence of the various IgG subtypes, was monitored. Fecal samples were also collected to determine the extent of IgA production. At the termination of the experiments the cytokine secretion profile for HBc153-stimulated splenocytes was determined for the following cytokines: IFN-gamma, IL-2, IL-4, IL-4 and IL-10. (Abstract shortened by UMI.)...