Preparation, characterization, and in ovo vaccination of dextran-spermine nanoparticle DNA vaccine coexpressing the fusion and hemagglutinin genes against Newcastle disease

Abstract

Plasmid DNA (pDNA)-based vaccines have emerged as effective subunit vaccines against viral and bacterial pathogens. In this study, a DNA vaccine, namely plasmid internal ribosome entry site-HN/F, was applied in ovo against Newcastle disease (ND). Vaccination was carried out using the DNA vaccine alone or as a mixture of the pDNA and dextran-spermine (D-SPM), a nanoparticle used for pDNA delivery. The results showed that in ovo vaccination with 40 μg pDNA/egg alone induced high levels of antibody titer (P<0.05) in specific pathogen-free (SPF) chickens at 3 and 4 weeks postvaccination compared to 2 weeks postvaccination. Hemagglutination inhibition (HI) titer was not significantly different between groups injected with 40 μg pDNA + 64 μg D-SPM and 40 μg pDNA at 4 weeks postvaccination (P>0.05). Higher antibody titer was observed in the group immunized with 40 μg pDNA/egg at 4 weeks postvaccination. The findings also showed that vaccination with 40 μg pDNA/egg alone was able to confer protection against Newcastle disease virus strain NDIBS002 in two out of seven SPF chickens. Although the chickens produced antibody titers 3 weeks after in ovo vaccination, it was not sufficient to provide complete protection to the chickens from lethal viral challenge. In addition, vaccination with pDNA/D-SPM complex did not induce high antibody titer when compared with naked pDNA. Therefore, it was concluded that DNA vaccination with plasmid internal ribosome entry site-HN/F can be suitable for in ovo application against ND, whereas D-SPM is not recommended for in ovo gene delivery.

Keywords:

• Newcastle disease
• DNA vaccine
• in ovo vaccination
• Newcastle disease virus
• dextran-spermine nanoparticle
• hemagglutinin and fusion

Acknowledgments

This work was funded by the Ministry of Science, Technology and Innovations (MOSTI), Malaysia, for the research grant (ERGS/1-2012/5527122), and Institute of Bioscience, Higher Institution Centre of Excellence (IBS HICoE) grant from the Ministry of Higher Education, Government of Malaysia for the support of the doctoral research work for Ms Masoumeh. Authors would like to thank Malaysia International Scholarship, Ministry of Higher Education, Government of Malaysia for the support of Dr Mohamed E El Zowalaty through a postdoctoral scholarship award conducted at the Laboratory of Vaccine and Immunotherapeutics, Institute of Bioscience, Malaysia.

Author contributions

AI, SDH, MHB, and ARO conceived and designed the study. MF, HM, PM, and MEZ carried out the experiments. MF, and HM performed the molecular genetic studies, immunoassays, sequence alignment, statistical analysis. MF, MEZ and PM performed the vaccination experiments. MF, HM, MEZ drafted the manuscript, all authors have contributed to writing and revising the manuscript. MEZ, MF, TJW, and AI revised the manuscript during all stages of submission. All authors read and approved the final paper.

Disclosure

The authors report no conflicts of interest in this work.