Canola oilseed‐ and Escherichia coli‐ derived hepatitis C virus (HCV) core proteins adjuvanted with oil bodies, induced robust Th1‐oriented immune responses in immunized mice

Induction of broad Th1 cellular immune responses and cytokines is crucial characteristics for vaccines against intracellular infections such as hepatitis C virus (HCV). Plants (especially oilseed tissues) and plant‐immunomodulators (like oil bodies) offer cost‐effective and scalable possibilities for the production of immunologically relevant and safe vaccine antigens and adjuvants, respectively. Herein, we provide data of the murine immunization by transgenic canola oilseed‐derived HCV core protein (HCVcp) soluble extract (TSE) and Escherichia coli‐ derived rHCVcp in combination with Canola oil bodies (oil) compared to that of the Freund’s (FA) adjuvant. Mice immunized by TSE+ oil developed both strong humeral (IgG) and Th1‐biased cellular responses, manifested by high levels of IFN‐γ and lower IgG1/IgG2a ratio and IL‐4 secretion. Results of the intracellular cytokine staining indicated that TSE+ oil immunization in mice triggered both CD4+ and CD8+ T cells to release IFN‐γ, while CD4+ cells were mostly triggered when FA was used. Analyses by qRT‐PCR indicated that a combination of rHCVcp/TSE with oil body induced high levels of IL‐10 cytokines compared to that of the FA adjuvant. These characteristics are important properties for the design of an HCV vaccine candidate and indicate the potential of Canola‐derived antigen and oil bodies in addressing these concerns.