DNA 介导的疫苗接种在母源抗体存在的情况下为肉鸡提供对传染性法氏囊病的保护。
DNA-mediated vaccination conferring protection against infectious bursal disease in broiler chickens in the presence of maternal antibody.
机构信息
Department of Comparative Pathobiology, School of Veterinary Medicine, Purdue University, 406 South University Street, West Lafayette, IN 47907-2065, USA.
出版信息
Vaccine. 2010 May 21;28(23):3936-43. doi: 10.1016/j.vaccine.2010.03.066. Epub 2010 Apr 13.
The objective of the present study was to determine if a DNA vaccine carrying large segment gene of infectious bursal disease virus (IBDV) could confer protection against infectious bursal disease (IBD) in broiler chickens in the presence of maternal antibody. Broiler chickens with maternal antibody titers to IBDV were intramuscularly injected with a DNA plasmid coding for VP2, VP3, and VP4 genes of IBDV strain variant E (VE) (P/VP243/E) at 1-day, 1-week, and/or 2 weeks old. The dose of P/VP243/E used ranging from 400microg to 10mg. Broiler chickens at 3 weeks old were orally challenged with IBDV strain (VE) and observed for 10 days. Only broiler chickens vaccinated with 7.5 or 10mg of P/VP243/E 3 times had 90 or 100% protection against challenge by IBDV strain VE and protected broiler chickens had significantly higher (P<0.05) bursa weight/body weight (B/B) ratios, significantly lower (P<0.05) bursal lesion scores, and the absence of IBDV antigens in bursae determined by immunofluorescent antibody assay (IFA). Antibody titers to IBDV as determined by enzyme-linked immunosorbent assay (ELISA) or virus neutralization (VN) assay in chickens of each group in each trial were gradually decreased prior to challenge. There was no significant difference (P>0.05) in ELISA or VN titers to IBDV among all groups of broiler chickens or among the groups of broiler chickens vaccinated with various dose of P/VP243/E before challenge. Broiler chickens in the groups receiving 7.5 or 10mg of P/VP243/E had significantly lower (P<0.05) ELISA or VN titers to IBDV than those in the challenge control (CC) groups or the other groups vaccinated with various dose of P/VP243/E after challenge. Broiler chickens in the groups vaccinated with 10mg of P/VP243/E 3 times had significantly higher (P<0.05) stimulation indices for IBDV-stimulated lymphocyte proliferation response than those in the vector control (VC) or CC group at 14, 21, 24, or 31 days after first DNA vaccination. The results indicated that DNA vaccination with DNA encoding large segment gene of IBDV confers protection against challenge by IBDV in broiler chickens with maternal antibody to IBDV.
本研究的目的是确定携带传染性法氏囊病病毒（IBDV）大段基因的 DNA 疫苗是否能在存在母源抗体的情况下为肉鸡提供对传染性法氏囊病（IBD）的保护。1 日龄、1 周龄和/或 2 周龄时，具有 IBDV 母源抗体滴度的肉鸡通过肌肉内注射编码 IBDV 株变异 E（VE）VP2、VP3 和 VP4 基因的 DNA 质粒（P/VP243/E）。使用的 P/VP243/E 剂量范围为 400μg 至 10mg。3 周龄的肉鸡经口感染 IBDV 株（VE），观察 10 天。仅接种 7.5 或 10mg P/VP243/E 3 次的肉鸡对 IBDV 株 VE 的攻击有 90%或 100%的保护作用，并且受保护的肉鸡的法氏囊重量/体重（B/B）比值显著更高（P<0.05），法氏囊病变评分显著更低（P<0.05），免疫荧光抗体检测（IFA）法检测法氏囊内无 IBDV 抗原。在每个试验的每组鸡中，通过酶联免疫吸附试验（ELISA）或病毒中和（VN）试验测定的针对 IBDV 的抗体滴度在攻毒前逐渐下降。在攻毒前，各组肉鸡的 ELISA 或 VN 对 IBDV 的抗体滴度无显著差异（P>0.05），或接种不同剂量 P/VP243/E 的各组肉鸡之间也无显著差异。接种 7.5 或 10mg P/VP243/E 的肉鸡的 ELISA 或 VN 对 IBDV 的抗体滴度明显低于攻毒对照组（CC）或接种不同剂量 P/VP243/E 的其他组。接种 10mg P/VP243/E 3 次的肉鸡在第 1 次 DNA 接种后 14、21、24 或 31 天时，针对 IBDV 刺激的淋巴细胞增殖反应的刺激指数明显高于载体对照组（VC）或 CC 组。结果表明，用编码 IBDV 大片段基因的 DNA 进行 DNA 免疫可提供对具有 IBDV 母源抗体的肉鸡的 IBDV 攻毒的保护。
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