U.S. Department of Agriculture, Exotic and Emerging Avian Viral Diseases Unit, U.S. National Poultry Research Center, Agricultural Research Service, Athens, Georgia, United States of America.
U.S. Department of Agriculture, Endemic Poultry Viral Diseases Unit, U.S. National Poultry Research Center, Agricultural Research Service, Athens, Georgia, United States of America.
PLoS One. 2024 Jul 16;19(7):e0307100. doi: 10.1371/journal.pone.0307100. eCollection 2024.
The outbreak of clade 2.3.4.4b H5 highly pathogenic avian influenza (HPAI) in North America that started in 2021 has increased interest in applying vaccination as a strategy to help control and prevent the disease in poultry. Two commercially available vaccines based on the recombinant herpes virus of turkeys (rHVT) vector were tested against a recent North American clade 2.3.4.4b H5 HPAI virus isolate: A/turkey/Indiana/22-003707-003/2022 H5N1 in specific pathogen free white leghorn (WL) chickens and commercial broiler chickens. One rHVT-H5 vaccine encodes a hemagglutinin (HA) gene designed by the computationally optimized broadly reactive antigen method (COBRA-HVT vaccine). The other encodes an HA gene of a clade 2.2 virus (2.2-HVT vaccine). There was 100% survival of both chicken types COBRA-HVT vaccinated groups and in the 2.2-HVT vaccinated groups there was 94.8% and 90% survival of the WL and broilers respectively. Compared to the 2.2-HVT vaccinated groups, WL in the COBRA-HVT vaccinated group shed significantly lower mean viral titers by the cloacal route and broilers shed significantly lower titers by the oropharyngeal route than broilers. Virus titers detected in oral and cloacal swabs were otherwise similar among both vaccine groups and chicken types. To assess antibody-based tests to identify birds that have been infected after vaccination (DIVA-VI), sera collected after the challenge were tested with enzyme-linked lectin assay-neuraminidase inhibition (ELLA-NI) for N1 neuraminidase antibody detection and by commercial ELISA for detection of antibodies to the NP protein. As early as 7 days post challenge (DPC) 100% of the chickens were positive by ELLA-NI. ELISA was less sensitive with a maximum of 75% positive at 10DPC in broilers vaccinated with 2.2-HVT. Both vaccines provided protection from challenge to both types of chickens and ELLA-NI was sensitive at identifying antibodies to the challenge virus therefore should be evaluated further for DIVA-VI.
2021 年在北美暴发的 2.3.4.4b 分支 H5 高致病性禽流感（HPAI）疫情增加了人们对应用疫苗作为控制和预防家禽疾病策略的兴趣。两种基于火鸡重组疱疹病毒（rHVT）载体的市售疫苗在无特定病原体的白来航鸡（WL）和商品肉鸡中针对最近的北美 2.3.4.4b 分支 H5 HPAI 病毒分离株 A/turkey/Indiana/22-003707-003/2022 H5N1 进行了测试。一种 rHVT-H5 疫苗编码了一种通过计算优化的广泛反应性抗原方法设计的血凝素（HA）基因（COBRA-HVT 疫苗）。另一种编码了 2.2 分支病毒的 HA 基因（2.2-HVT 疫苗）。COBRA-HVT 接种组的两种鸡的存活率均为 100%，2.2-HVT 接种组的 WL 和肉鸡的存活率分别为 94.8%和 90%。与 2.2-HVT 接种组相比，COBRA-HVT 接种组的 WL 通过泄殖腔途径排出的平均病毒滴度显著降低，肉鸡通过口腔途径排出的滴度也显著低于肉鸡。两种疫苗组和鸡类型的口腔和泄殖腔拭子中检测到的病毒滴度相似。为了评估用于鉴定接种后感染的鸟类的基于抗体的检测方法（DIVA-VI），在攻毒后采集的血清用酶联凝集素测定-神经氨酸酶抑制（ELLA-NI）检测 N1 神经氨酸酶抗体，并通过商业 ELISA 检测 NP 蛋白的抗体。在攻毒后 7 天（DPC），100%的鸡通过 ELLA-NI 呈阳性。ELISA 的灵敏度较低，2.2-HVT 接种的肉鸡在 10DPC 时最大阳性率为 75%。两种疫苗都能为两种类型的鸡提供针对攻毒的保护，ELLA-NI 能灵敏地识别针对攻毒病毒的抗体，因此应进一步评估用于 DIVA-VI。
