Effects of DDA, CpG-ODN, and plasmid-encoded chicken IFN-γ on protective immunity by a DNA vaccine against IBDV in chickens

Abstract

This study examined the adjuvant effects of dimethyl dioctadecyl ammonium bromide (DDA), CpG oligodeoxynucleotides (CpG-ODN), and chicken interferon-γ (ChIFN-γ) on a DNA vaccine (pcDNA-VP243) against the infectious bursal disease virus (IBDV). A plasmid encoding chicken IFN-ã was constructed. Twice at 2-week intervals, two-week-old chickens were injected intramuscularly and intraperitoneally with either a DNA vaccine alone or a DNA vaccine together with the respective adjuvants. On week 2 after the second immunization, the chickens were orally challenged with the highly virulent IBDV. The groups that received the DNA vaccines plus either DDA or CpG-ODN showed significantly lower survival rates than the group that received the DNA vaccine alone. However, the survival rates for the DNA vaccine alone and for the DNA vaccine plus ChIFN-γ were similar. The chickens had no detectable antibodies to the IBDV before the challenge but all the surviving chickens in all groups except for the normal control group showed the induction of antibodies to the IBDV at day 10 after the challenge. As judged by the lymphocyte proliferation assays using the a WST-8 solution performed on the peripheral blood and splenic lymphocytes, the stimulation indices (SI) of the peripheral blood lymphocytes in all groups except for the normal control group were similar immediately before the challenge. At 10 days post-challenge, the SI for DNA vaccine plus either CpG-ODN or ChIFN-γ was similar to that of the DNA vaccine control group. For splenic lymphocytes, the SI in the DNA vaccine plus CpG-ODN and DNA vaccine plus ChIFN-γ groups were higher than for the DNA vaccine control. These results suggest that DDA actually compromises the protection against the IBDV by DNA vaccine, and CpG-ODN and IFN-γ had no significant effect.

Multivalent HA DNA Vaccination Protects against Highly Pathogenic H5N1 Avian Influenza Infection in Chickens and Mice

“…DNA vaccines have been shown to elicit robust immune responses in various animal species, from mice to nonhuman primates [1][2][3][4][5][6][7][8][9][10][11]. In human trials, these vaccines elicit cellular and humoral immune responses against various infectious agents, including influenza, SARS, SIV and HIV.…”

Development of a subunit vaccine containing recombinant chicken anemia virus VP1 and pigeon IFN-γ

“…9% protein has been shown to be functional in chicken cells (Fringuelli et al, 2010). A previous study shows that INF-␥ has adjuvant effects and increases immune responses against viral diseases when used in veterinary vaccines (Park et al, 2009;Roh et al, 2006;Wang et al, 2013).…”

Protection of chicken against very virulent IBDV provided by in ovo priming with DNA vaccine and boosting with killed vaccine and the adjuvant effects of plasmid-encoded chicken interleukin-2 and interferon-γ

“…For example, chicken interleukin-2 (ChIL-2) enhanced the immunogenicity of DNA vaccines against IBDV [12], but chicken IFN-γ (ChIFN-γ) did not [10,32]. …”