Comparative evaluation of live marker vaccine candidates 鈥淐P7_E2alf鈥?and 鈥渇lc11鈥?along with C-strain 鈥淩iems鈥?after oral vaccination

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• 作者：Sandra Blome^a ; Andrea Aebischer^b ; Elke Lange^a ; Martin Hofmann^b ; Immanuel Leifer^a ; ^b ; Willie Loeffen^c ; Frank Koenen^d ; Martin Beer^a ; ^{martin.beer@fli.bund.de}
• 关键词：Classical swine fever virus (CSFV) ; Candidate marker vaccines ; CP7_E2alf ; flc11 ; C-strain vaccine
• 刊名：Veterinary Microbiology
• 出版年：2012
• 期刊代码：106_03781135
• 类别：abs
• 出版时间：6 July, 2012
• 卷：158
• 期：1-2
• 页码：42-59
• 文件大小：529 K

摘要

Due to the tremendous socio-economic impact of classical swine fever (CSF) outbreaks, emergency vaccination scenarios are continuously under discussion. Unfortunately, all currently available vaccines show restrictions either in terms of marker capacities or immunogenicity. Recent research efforts were therefore directed at the design of new modified live marker vaccines. Among the most promising candidates the chimeric pestiviruses 鈥淐P7_E2alf鈥?and 鈥渇lc11鈥?were identified. Within an international research project, these candidates were comparatively tested in challenge experiments after a single oral vaccination. Challenge infection was carried out with highly virulent CSF virus strain 鈥淜oslov鈥? 14 or 21 days post vaccination (dpv), respectively. Safety, efficacy, and marker potential were addressed. All assessments were done in comparison with the conventional 鈥済old standard鈥?C-strain 鈥淩iems鈥?vaccine. In addition to the challenge trials, multiple vaccinations with both candidates were performed to further assess their marker vaccine potential.

All vaccines were safe and yielded full protection upon challenge 21 days post vaccination. Neither serological nor virological investigations showed major differences among the three vaccines. Whereas CP7_E2alf also provided clinical protection upon challenge at 14 days post vaccination, only 50%of animals vaccinated with flc11, and 83%vaccinated with C-strain 鈥淩iems鈥?survived challenge at this time point. No marked differences were seen in protected animals. Despite the fact that all multiple-vaccinated animals stayed sero-negative in the accompanying marker test, the discriminatory assay remains a weak point due to delayed or inexistent detection of some of the vaccinated and subsequently infected animals. Nevertheless, the potential as live marker vaccines could be confirmed for both vaccine candidates. Future efforts will therefore be directed at the licensing of 鈥淐p7_E2alf鈥?as the first live marker vaccine for CSF.