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首页> 外文期刊>Vaccine >Dose response effects of avian influenza (H7N7) vaccination of chickens: Serology, clinical protection and reduction of virus excretion
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Dose response effects of avian influenza (H7N7) vaccination of chickens: Serology, clinical protection and reduction of virus excretion

机译：鸡禽流感（H7N7）疫苗的剂量反应效应：血清学，临床保护和减少病毒排泄

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Knowledge of the relation between the antigen content of inactivated avian influenza (AI) vaccines, the serological response after vaccination and protection of vaccinated animals is important for the choice of optimal vaccines and vaccination regimes as well as for the assessment of criteria for the licensing of new AI-vaccines. We studied this relation in a dose response study using inactivated H7N7 avian influenza vaccines with varying antigen content. The serological response depended on the antigen content of the vaccines. Anti-AI antibodies were detected most frequently with ELISA, followed by the virus neutralisation test and the haemagglutination inhibition (HI) assay. Chickens with measurable HI-antibody titers, using homologous H7N7 antigen, were all protected against clinical disease after challenge with highly pathogenic A/chicken/Netherlands/621557/03 H7N7 virus. However, in these chickens high levels of virus could still be present on days 2-4 after challenge. The reduction of virus titers after challenge, depended on the antigen content of the vaccines as well as on the serum antibody titers. While 10 haemagglutinating units (HAU), equivalent to 0.8mug haemagglutinin (HA) protein, per vaccine dose was sufficient for prevention of clinical disease, 128 HAU (9mug HA) per dose was required for reduction of virus titers in all chickens to 10(3) egg-infectious dose 50% (EID(50)) or less. In order to reduce virus titers below 10(3)EID(50) per swab a HI-antibody titer of 64 was required. After use of the vaccine with the highest antigen content, challenge still induced a booster of antibody titers which is indicative of replication of challenge virus.
机译：灭活禽流感（AI）疫苗的抗原含量，疫苗接种后的血清学应答和疫苗接种动物的保护之间的关系的知识对于选择最佳疫苗和疫苗接种方案以及评估许可的标准很重要。新的AI疫苗。我们在剂量反应研究中使用不同抗原含量的灭活H7N7禽流感疫苗研究了这种关系。血清学应答取决于疫苗的抗原含量。 ELISA检测抗AI抗体的频率最高，随后进行病毒中和测试和血凝抑制（HI）分析。使用高致病性A /鸡/荷兰/荷兰/ 621557/03 H7N7病毒攻击后，使用同源H7N7抗原可测量的HI抗体滴度的鸡都受到了临床疾病的保护。但是，在这些鸡中，攻击后第2-4天仍可能存在高水平的病毒。攻击后病毒滴度的降低取决于疫苗的抗原含量以及血清抗体滴度。虽然每剂疫苗10个血凝单位（HAU）相当于0.8杯血凝素（HA）蛋白，足以预防临床疾病，但每剂需要128 HAU（9杯HA）才能将所有鸡的病毒滴度降低至10（ 3）鸡蛋感染剂量为50％（EID（50））或以下。为了将每支拭子的病毒滴度降低至10（3）EID（50）以下，需要HI抗体滴度为64。在使用具有最高抗原含量的疫苗后，挑战仍然诱导了抗体效价的增强，这表明挑战病毒的复制。

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