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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-gamma.

Park JH, Sung HW, Yoon BI, Kwon HM - J. Vet. Sci. (2009)

Bottom Line: The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score.In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity.These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Veterinary Microbiology, School of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Korea.

ABSTRACT
The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-gamma were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-gamma (ChIFN-gamma) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killedvaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.

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The mitogenic responses of peripheral blood lymphocytes prepared from chickens before and after being challenged with the very virulent IBDV SH/92 strain. Cells were stimulated with Con A (1.25 µg/well) and each value was presented as the mean of the ELISA optical density obtained from randomly selected chickens ± SD. Within same day, values followed by different lowercase superscripts are significantly different (p < 0.05). Stimulation index (SI) = (mean OD of ConA-stimulated cells) / (mean OD of unstimulated cells).
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Figure 3: The mitogenic responses of peripheral blood lymphocytes prepared from chickens before and after being challenged with the very virulent IBDV SH/92 strain. Cells were stimulated with Con A (1.25 µg/well) and each value was presented as the mean of the ELISA optical density obtained from randomly selected chickens ± SD. Within same day, values followed by different lowercase superscripts are significantly different (p < 0.05). Stimulation index (SI) = (mean OD of ConA-stimulated cells) / (mean OD of unstimulated cells).

Mentions: The effectiveness of a prime-boost vaccination strategy in enhancing the immunogenicity and protective effect of a DNA vaccine against IBDV was investigated. The experimental groups were immunized with DNA vaccine alone or vaccine mixed with selected genetic adjuvants at day 18 of embryonation, and boosted with killed vaccine at 1 week of age. The chickens were challenged with vvIBDV at 3 weeks of age. After 10 days of observation, the mortality rate, presence of IBDV RNA, B/B ratios, serum antibody titers, and ConA-induced peripheral blood lymphocyte proliferation were recorded (Table 1, Figs. 2 and 3).


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-gamma.

Park JH, Sung HW, Yoon BI, Kwon HM - J. Vet. Sci. (2009)

The mitogenic responses of peripheral blood lymphocytes prepared from chickens before and after being challenged with the very virulent IBDV SH/92 strain. Cells were stimulated with Con A (1.25 µg/well) and each value was presented as the mean of the ELISA optical density obtained from randomly selected chickens ± SD. Within same day, values followed by different lowercase superscripts are significantly different (p < 0.05). Stimulation index (SI) = (mean OD of ConA-stimulated cells) / (mean OD of unstimulated cells).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2801112&req=5

Figure 3: The mitogenic responses of peripheral blood lymphocytes prepared from chickens before and after being challenged with the very virulent IBDV SH/92 strain. Cells were stimulated with Con A (1.25 µg/well) and each value was presented as the mean of the ELISA optical density obtained from randomly selected chickens ± SD. Within same day, values followed by different lowercase superscripts are significantly different (p < 0.05). Stimulation index (SI) = (mean OD of ConA-stimulated cells) / (mean OD of unstimulated cells).
Mentions: The effectiveness of a prime-boost vaccination strategy in enhancing the immunogenicity and protective effect of a DNA vaccine against IBDV was investigated. The experimental groups were immunized with DNA vaccine alone or vaccine mixed with selected genetic adjuvants at day 18 of embryonation, and boosted with killed vaccine at 1 week of age. The chickens were challenged with vvIBDV at 3 weeks of age. After 10 days of observation, the mortality rate, presence of IBDV RNA, B/B ratios, serum antibody titers, and ConA-induced peripheral blood lymphocyte proliferation were recorded (Table 1, Figs. 2 and 3).

Bottom Line: The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score.In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity.These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Veterinary Microbiology, School of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Korea.

ABSTRACT
The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-gamma were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-gamma (ChIFN-gamma) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killedvaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.

Show MeSH
Related in: MedlinePlus