Kapczynski Darrell R, Sylte Matthew J, Killian Mary L, Torchetti Mia K, Chrzastek Klaudia, Suarez David L
Exotic and Emerging Avian Viral Diseases Research Unit, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Road, Athens, GA, 30605, United States.
Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, 1920 Dayton Avenue, Ames, IA, 50010, United States.
Vet Immunol Immunopathol. 2017 Sep;191:74-79. doi: 10.1016/j.vetimm.2017.08.001. Epub 2017 Aug 10.
Between December 2014 and June 2015, North America experienced the largest recorded foreign animal disease outbreak with over 47 million poultry dead or euthanized from viral exposure to a clade 2.3.4.4 H5 highly pathogenic avian influenza (HPAI) epizootic. Soon after the epizootic began, the U.S. Department of Agriculture (USDA) began testing the efficacy of different vaccines as a possible future control strategy. The aim of these studies were to evaluate the efficacy three H5 vaccines to aid in control of HPAI in commercial turkeys. Three different vaccine technologies were evaluated for efficacy: 1) inactivated reverse genetic laboratory-generated virus encoding a clade 2.3.4.4 H5 hemagglutinin (HA) gene (rgH5), 2) recombinant turkey herpesvirus encoding a clade 2.2. H5 HA (rHVT-AI), and 3) recombinant replication-deficient alphavirus RNA particle vaccine encoding a clade 2.3.4.4 H5 HA (RP-H5). All vaccines tested significantly (P<0.01) increased survival rates between vaccinated and sham vaccinated groups of poults challenged with A/turkey/Minnesota/12582/2015 clade 2.3.4.4 H5N2 HPAI. The rgH5 vaccine had detectable serum hemagglutination inhibition (HI) antibody against the challenge virus, and significantly reduced the frequency and level of viral shedding from oropharyngeal and cloacal swabs at days 2 and 4 post-challenge. Vaccination with only rHVT-AI or RP-H5 was not 100% protective, and failed to significantly reduce viral shedding post-challenge. A combined prime and boost strategy with the rHVT-AI and RP-H5, or rHVT-AI and rgH5, was 100% protective against lethal H5N2 HPAI challenge. Results of these studies led to USDA conditional approval of commercially available recombinant vaccines for use in turkeys as a control measure for clade 2.3.4.4 H5 HPAI epizootics.
2014年12月至2015年6月期间，北美经历了有记录以来最大规模的外来动物疾病疫情，超过4700万只家禽因接触2.3.4.4分支H5高致病性禽流感（HPAI）病毒而死亡或被安乐死。疫情开始后不久，美国农业部（USDA）就开始测试不同疫苗的效果，将其作为未来可能的控制策略。这些研究的目的是评估三种H5疫苗对控制商业火鸡中HPAI的效果。评估了三种不同疫苗技术的效果：1）编码2.3.4.4分支H5血凝素（HA）基因的灭活反向遗传实验室产生病毒（rgH5），2）编码2.2分支H5 HA的重组火鸡疱疹病毒（rHVT-AI），3）编码2.3.4.4分支H5 HA的重组复制缺陷型甲病毒RNA颗粒疫苗（RP-H5）。所有测试疫苗在受A/火鸡/明尼苏达/12582/2015 2.3.4.4分支H5N2 HPAI攻击的雏禽接种组和假接种组之间均显著（P<0.01）提高了存活率。rgH5疫苗具有针对攻击病毒的可检测血清血凝抑制（HI）抗体，并在攻毒后第2天和第4天显著降低了口咽和泄殖腔拭子的病毒脱落频率和水平。仅接种rHVT-AI或RP-H5不能提供100%的保护，且未能显著降低攻毒后的病毒脱落。rHVT-AI与RP-H5或rHVT-AI与rgH5联合的初免和加强策略对致死性H5N2 HPAI攻击具有100%的保护作用。这些研究结果导致美国农业部有条件批准将市售重组疫苗用于火鸡，作为2.3.4.4分支H5 HPAI疫情的控制措施。
