Effect of emergency FMD vaccine antigen payload on protection, sub-clinical infection and persistence following direct contact challenge of cattle
Effect of emergency FMD vaccine antigen payload on protection, sub-clinical infection and persistence following direct contact challenge of cattle
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DOI：
10.1016/j.vaccine.2006.01.037
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发表时间：
2006-04-12
期刊：
影响因子：
5.5
通讯作者：
Barnett, PV
中科院分区：
文献类型：
--
作者：
Cox, SJ;Voyce, C;Barnett, PV
先前在接种紧急口蹄疫（FMD）疫苗的绵羊中进行的工作表明，增加抗原有效负载可以抑制局部病毒复制，从而在用与疫苗株同源的病毒间接气溶胶激发后保持持续性。本文所述的工作进一步使用牛和更严重的半异源直接接触挑战研究了这种可能性。检查攻毒后接种和未接种牛中病毒复制和排泄的定量动力学。进行了两项实验，各涉及20头接种牛和5头未接种牛。先前报道的第一个实验使用了O-1 Manisa疫苗（18 PD 50）[考克斯SJ、Voyce C、Parida S、Reid SM、Hamblin PA、Paton DJ等人。牛紧急FMD疫苗接种后对直接接触挑战的保护以及对口咽病毒排泄的影响。Vaccine 2005;23：1106-13]。相同的疫苗用于本文所述的第二个实验，不同之处在于抗原有效载荷每牛剂量增加10倍，导致攻毒前FMD病毒中和抗体滴度显著更高。接种后21天，牛接受了5天FMD病毒直接接触攻毒，攻毒来自24小时前感染O UKG 34/2001的另外5头未接种牛。所有接种牛（不考虑抗原有效载荷）均获得预防临床疾病的保护。在两个实验的动物中均检测到亚临床口咽感染，但在接种疫苗的动物中，直接接触攻毒后不久的病毒复制水平显著降低。用10倍抗原有效载荷免疫的牛更容易清除病毒，因此与单强度疫苗相比，攻毒后28天持续感染的动物较少。在严峻的挑战之后，两个实验的结果表明，使用紧急疫苗可以防止或减少局部病毒复制，从而大大减少释放到环境中的病毒量，特别是在暴露后的早期。此外，增加疫苗的抗原有效载荷可以减少亚临床感染，导致更少的持续感染的病毒携带动物。(c)2006爱思唯尔有限公司保留所有权利。
Previous work, in sheep vaccinated with emergency foot-and-mouth disease (FMD) vaccine, indicated the benefit of increasing the antigen payload in inhibiting local virus replication and consequently persistence following an indirect aerosol challenge with a virus homologous to the vaccine strain. The work presented here investigates this possibility further using cattle and a more severe semi-heterologous direct contact challenge. The quantitative dynamics of virus replication and excretion in both vaccinated and non-vaccinated cattle following challenge are examined. Two experiments were carried out each involving 20 vaccinated and 5 non-vaccinated cattle. An O-1 Manisa vaccine (18 PD50) was used for the first, previously reported experiment [Cox SJ, Voyce C, Parida S, Reid SM, Hamblin PA, Paton DJ, et al. Protection against direct contact challenge following emergency FMD vaccination of cattle and the effect on virus excretion from the oropharynx. Vaccine 2005;23:1106-13]. The same vaccine was used for the second experiment described in this paper except the antigen payload was increased 10-fold per bovine dose, resulting in significantly higher FMD virus neutralising antibody titres prior to challenge. Twenty-one days post-vaccination the cattle received a 5-day direct contact challenge with FMD virus from five further non-vaccinated cattle infected 24h earlier with O UKG 34/2001. All vaccinated cattle regardless of antigen payload were protected against clinical disease. Sub-clinical oropharyngeal infection was detected in animals from both experiments but the level of virus replication shortly after direct contact challenge was significantly reduced in vaccinated animals. Cattle immunised with the 10-fold antigen payload cleared the virus more readily and consequently at 28 days post-challenge fewer animals were persistently infected compared to the single strength vaccine. Following a severe challenge, the results from both experiments show that use of emergency vaccine can prevent or decrease local virus replication and thereby dramatically reduce the amount of virus released into the environment, particularly during the early post-exposure period. Additionally, increasing the antigen payload of the vaccine may reduce sub-clinical infection, leading to fewer persistently infected virus carrier animals. (c) 2006 Elsevier Ltd. All rights reserved.