Development of oral DNA vaccine based on chitosan nanoparticles for the immunization against reddish body iridovirus in turbots (Scophthalmus maximus)

• Published in: Aquaculture 2016-02, Vol.452, p.263-271
• Main Authors: Zheng, Fengrong, Liu, Hongzhan, Sun, Xiuqin, Zhang, Yongqiang, Zhang, Baiyu, Teng, Zhaojun, Hou, Yongjiang, Wang, Bo
• Format: Article
• Language: English
• Subjects: Aquaculture; Deoxyribonucleic acid; DNA; Eukaryotes; Eukaryotic cell; Fish; Immune responses; Iridovirus; Marine; Plasmid DNA chitosan nanoparticles (pDNA-CS-NPs); Plasmids; Scophthalmus maximus; Turbot reddish body iridovirus; Vaccines
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2015.11.013

Turbot reddish body iridovirus (TRBIV), a piscine iridovirus, causes viral reddish body syndrome (VRBS) in turbot and is highly lethal to the fish. Infection of the virus hampers the development of turbot aquaculture. Hence, it is important to develop a preventive vaccine. In our previous study, we constructed and evaluated the immunization efficacy of the recombinant plasmid, pEGFP-N2-TRBIV-MCP. In the present study, an oral nanoparticle-based DNA vaccine against TRBIV was developed to evaluate the immunization effectiveness in turbots (Scophthalmus maximus) through oral administration. We prepared chitosan nanoparticles enwrapping plasmid DNA using ionic gelation process, and the characteristics of chitosan nanoparticles were analyzed by transmission electron microscope and Malvin ZS analyzer. The results revealed that the chitosan nanoparticle plasmids encoding DNA (pDNA-CS-NPs) were spherical shape with the particle size and zeta potential of 145.5±1.5nm and 24.3±0.5, respectively. The loading rate and encapsulation efficiency were 92.8±1.38% and 63.7±0.89%, respectively. In vitro transfection, pDNA-CS-NPs was transferred into eukaryotic cells, turbot cell TK line, and transient expression of pDNA-CS-NPs was detected by RT-PCR and laser scanning confocal microscope. After oral administration, the expression of the antigen gene could be detected in different tissues of turbots (S. maximus) at 20 and 40days post-vaccination. The pDNA-CS-NPs clearly induced an innate and specific immune response, and significantly up-regulated the expression of MHCIα, IIα, IFN-1, IFN-g, Mx-1, IL8 and Mx. In addition, strong protection with relative survival rate of 68% was recorded in the orally-vaccinated turbots, which could produce the detectable level of anti-TRBIV antibody during 90days. These data in this study suggested that pDNA-CS-NPs were promising carriers for plasmid DNA vaccine through oral vaccination. This method could be extended to the development of other oral vaccines and applied in other fish species against TRBIV. In this work, an oral nanoparticle-based DNA vaccine against TRBIV was developed to evaluate the immunization effectiveness in turbots (S. maximus) through oral administration. We prepared chitosan nanoparticles enwrapping plasmid DNA using ionic gelation process, and the characteristics of chitosan nanoparticles were analyzed by transmission electron microscope and Malvin ZS analyzer. I hope this paper is suitable for aquaculture. •Turbot r