RESUMO
BACKGROUND: Plant viruses can be employed as versatile vectors for the production of vaccines by expressing immunogenic epitopes on the surface of chimeric viral particles. Although several viruses, including tobacco mosaic virus, potato virus X and cowpea mosaic virus, have been developed as vectors, we aimed to develop a new viral vaccine delivery system, a bamboo mosaic virus (BaMV), that would carry larger transgene loads, and generate better immunity in the target animals with fewer adverse environmental effects. METHODS: We engineered the BaMV as a vaccine vector expressing the antigenic epitope(s) of the capsid protein VP1 of foot-and-mouth disease virus (FMDV). The recombinant BaMV plasmid (pBVP1) was constructed by replacing DNA encoding the 35 N-terminal amino acid residues of the BaMV coat protein with that encoding 37 amino acid residues (T128-N164) of FMDV VP1. RESULTS: The pBVP1 was able to infect host plants and to generate a chimeric virion BVP1 expressing VP1 epitopes in its coat protein. Inoculation of swine with BVP1 virions resulted in the production of anti-FMDV neutralizing antibodies. Real-time PCR analysis of peripheral blood mononuclear cells from the BVP1-immunized swine revealed that they produced VP1-specific IFN-gamma. Furthermore, all BVP1-immunized swine were protected against FMDV challenge. CONCLUSION: Chimeric BaMV virions that express partial sequence of FMDV VP1 can effectively induce not only humoral and cell-mediated immune responses but also full protection against FMDV in target animals. This BaMV-based vector technology may be applied to other vaccines that require correct expression of antigens on chimeric viral particles.
Assuntos
Epitopos/imunologia , Vírus da Febre Aftosa/imunologia , Vírus de Plantas/genética , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Western Blotting , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Chenopodium quinoa/virologia , DNA Recombinante/genética , DNA Recombinante/imunologia , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Epitopos/genética , Epitopos/metabolismo , Vírus da Febre Aftosa/genética , Vetores Genéticos/genética , Interferon gama/sangue , Microscopia Eletrônica , Modelos Genéticos , Reação em Cadeia da Polimerase , Sasa/virologia , Suínos , Vacinação , Vacinas Virais/genética , Vírion/genética , Vírion/imunologia , Vírion/ultraestruturaRESUMO
Japanese encephalitis virus (JEV) is among the major threats to public health in Asia. For disease control and prevention, the efficient production of safe and effective vaccines against JEV is in urgent need. In this study, we produced a plant-made JEV vaccine candidate using a chimeric virus particle (CVP) strategy based on bamboo mosaic virus (BaMV) for epitope presentation. The chimeric virus, designated BJ2A, was constructed by fusing JEV envelope protein domain III (EDIII) at the N-terminus of BaMV coat protein, with an insertion of the foot-and-mouth disease virus 2A peptide to facilitate the production of both unfused and epitope-presenting for efficient assembly of the CVP vaccine candidate. The strategy allowed stable maintenance of the fusion construct over long-term serial passages in plants. Immuno-electron microscopy examination and immunization assays revealed that BJ2A is able to present the EDIII epitope on the surface of the CVPs, which stimulated effective neutralizing antibodies against JEV infection in mice. This study demonstrates the efficient production of an effective CVP vaccine candidate against JEV in plants by the BaMV-based epitope presentation system.