Production and immunogenicity of a plant-produced beak and feather disease virus vaccine in Japanese quails

Abstract

Beak and feather disease virus (BFDV), a single-stranded DNA virus, infects endangered psittacine species, including the South African Cape parrot. The disease is highly contagious and can be transmitted through contact with contaminated faeces, crop secretions, and feather and skin dander. To date, there is no vaccine or cure available for BFDV. The production of an effective vaccine depends on having a production platform and methods that are both easy to use and capable of yielding a significant amount of protein that will induce a sufficient immune response. Therefore, the aim of this study was to produce a plant-based BFDV vaccine candidate and to evaluate its ability to elicit an immune response in birds. Recombinant BFDV capsid protein (CP) was transiently expressed in Nicotiana benthamiana and purified using density gradient ultracentrifugation. Japanese quails were immunized with purified BFDV CP. Yolk-derived IgY was purified by water dilution and salt precipitation, and its specificity was verified by western blot analysis. The expression levels of the coat protein increased from non-detectable to an average accumulation of 1.58 mg/kg of fresh plant tissue biomass, and antibodies against BFDV CP were detected in both the blood and eggs of immunized quails, indicating that vaccination with BFDV CP successfully elicited a humoral immune response. This study demonstrates that heterologous expression in plants is a viable method for producing BFDV CP. To the best of our knowledge, this is the first study to show the antibody response to a plant-produced BFDV antigen in a quail model. Given that the presence of anti-CP antibodies in infected birds is associated with immunity, this system can potentially be used to produce a vaccine against BFDV.

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