Department of Population Health, College of Veterinary Medicine, Poultry Diagnostic and Research Center, University of Georgia, Athens, 30602, USA.
Avian Pathol. 2012;41(1):21-31. doi: 10.1080/03079457.2011.631983.
Viral vector vaccines using fowl poxvirus (FPV) and herpesvirus of turkey (HVT) as vectors and carrying infectious laryngotracheitis virus (ILTV) genes are commercially available to the poultry industry in the USA. Different sectors of the broiler industry have used these vaccines in ovo or subcutaneously, achieving variable results. The objective of the present study was to determine the efficacy of protection induced by viral vector vaccines as compared with live-attenuated ILTV vaccines. The HVT-LT vaccine was more effective than the FPV-LT vaccine in mitigating the disease and reducing levels of challenge virus when applied in ovo or subcutaneously, particularly when the challenge was performed at 57 days rather than 35 days of age. While the FPV-LT vaccine mitigated clinical signs more effectively when administered subcutaneously than in ovo, it did not reduce the concentration of challenge virus in the trachea by either application route. Detection of antibodies against ILTV glycoproteins expressed by the viral vectors was a useful criterion to assess the immunogenicity of the vectors. The presence of glycoprotein I antibodies detected pre-challenge and post challenge in chickens vaccinated with HVT-LT indicated that the vaccine induced a robust antibody response, which was paralleled by significant reduction of clinical signs. The chicken embryo origin vaccine provided optimal protection by significantly mitigating the disease and reducing the challenge virus in chickens vaccinated via eye drop. The viral vector vaccines, applied in ovo and subcutaneously, provided partial protection, reducing to some degree clinical signs, and challenge VIRUS replication in the trachea.
在美国，家禽业可使用禽痘病毒（FPV）和火鸡疱疹病毒（HVT）作为载体，携带传染性喉气管炎病毒（ILTV）基因的病毒载体疫苗。肉鸡产业的不同部门已经在鸡胚期或皮下使用了这些疫苗，取得了不同的效果。本研究的目的是确定病毒载体疫苗与活毒减毒 ILTV 疫苗相比诱导的保护效力。HVT-LT 疫苗在减轻疾病和减少攻毒病毒水平方面比 FPV-LT 疫苗更有效，尤其是在 57 日龄而不是 35 日龄攻毒时。虽然 FPV-LT 疫苗在皮下接种时比在鸡胚期接种更有效地减轻临床症状，但无论是通过哪种应用途径，都不能降低气管中攻毒病毒的浓度。检测针对病毒载体表达的 ILTV 糖蛋白的抗体是评估载体免疫原性的有用标准。接种 HVT-LT 的鸡在攻毒前和攻毒后检测到针对糖蛋白 I 的抗体表明疫苗诱导了强烈的抗体反应，这与临床症状的显著减轻相平行。鸡胚来源疫苗通过滴眼接种为鸡提供了最佳保护，显著减轻了疾病，降低了攻毒病毒。在鸡胚期或皮下接种的病毒载体疫苗提供了部分保护，在一定程度上减轻了临床症状，并降低了气管中的攻毒病毒复制。
