title: Enhancement of glycoprotein-based DNA vaccine for viral hemorrhagic septicemia virus (VHSV) via addition of the molecular adjuvant, DDX41.
abstract: The use of molecular adjuvants to improve the immunogenicity of DNA vaccines has been thoroughly studied in recent years. Glycoprotein (G)-based DNA vaccines had been proven to be effective in combating infection against Rhabdovirus (especially infectious hematopoietic necrosis virus, IHNV) in salmonids. DDX41 is a helicase known to induce antiviral and inflammatory responses by inducing a type I IFN innate immune response. To gain more information regarding G-based DNA vaccines in olive flounder (Paralicthys olivaceus), we tried to develop a more efficient G-based DNA vaccine by adding a molecular adjuvant, DDX41. We designed a DNA vaccine in which the VHSV glycoprotein (G-protein) and DDX41 were driven by the EF-1α and CMV promoters, respectively. Olive flounders were intramuscularly immunized with 1 μg of plasmids encoding the G-based DNA vaccine alone (pEF-G), the molecular adjuvant alone (pEF-D), or the vaccine-adjuvant construct (pEF-GD). At two different time points, 15 and 30 days later, the fish were intraperitoneally infected with VHSV (100 μL; 1 × 106TCID50/mL). Our assays revealed that the plasmid constructs showed up-regulated expression of IFN-1 and its associated genes at day 3 post-vaccination in both kidney and spleen samples. Specifically, pEF-GD showed statistically higher expression of immune response genes than pEF-G and pEF-D treated group (p < 0.05/p < 0.001). After VHSV challenge, the fish group treated with pEF-GD showed higher survival rate than the pEF-G treated group, though difference was not statistically significant in the 15 dpv challenged group however in the 30 dpv challenged group, the difference was statistically significant (p < 0.05). Together, these results clearly demonstrate that DDX41 is an effective adjuvant for the G-based DNA vaccine in olive flounder. Our novel findings could facilitate the development of more effective DNA vaccines for the aquaculture industry.
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Jassy Mary S
authors.initials: JMS
authors.lastname: Lazarte
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Young Rim
authors.initials: YR
authors.lastname: Kim
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Jung Seok
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Se Pyeong
authors.initials: SP
authors.lastname: Im
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Si Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Jae Wook
authors.initials: JW
authors.lastname: Jung
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Jaesung
authors.initials: J
authors.lastname: Kim
authors.affiliation: BluGen Korea, Busan, South Korea.
authors.forename: Woo Jai
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Laboratory of Aquatic Animal Diseases, College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea. Electronic address: jungts@gnu.ac.kr.
authors.forename: Tae Sung
authors.initials: TS
authors.lastname: Jung
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D053487:DEAD-box RNA Helicases / Q000494:pharmacology*; D029941:Fish Proteins / Q000494:pharmacology*; D005412:Flatfishes; D006023:Glycoproteins / Q000276:immunology; D031941:Hemorrhagic Septicemia, Viral / Q000517:prevention & control* / Q000821:virology; D007109:Immunity / Q000187:drug effects; D029141:Novirhabdovirus / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology; D014764:Viral Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D029941:Fish Proteins; D006023:Glycoproteins; D019444:Vaccines, DNA; D014764:Viral Proteins; D014765:Viral Vaccines; D053487:DEAD-box RNA Helicases
keywords: DDX41; Glycoprotein; Innate immune system; Interferon; VHSV