Habibi M, Karimi V, Langeroudi A G, Ghafouri S A, Hashemzadeh M, Farahani R K, Maghsoudloo H, Abdollahi H, Seifouri P
Acta Virol. 2017;61(2):150-160. doi: 10.4149/av_2017_02_04.
Avian infectious bronchitis (IB) is a worldwide chicken disease, caused by avian infectious bronchitis virus (IBV) which infects all commercial poultry lines. The present study was done to evaluate protection caused by two different serotype vaccines (Massachusetts and 793/B) in order to evaluate protection against challenge with IS/1494/06-like virus (variant 2-like virus), which is prevalent in the Middle East. SPF chickens were divided into four groups (n = 20). First and second group as negative control group and non-vaccinated-challenged group received no vaccine. Groups 3 and 4 received H120-H120 and H120-1/96 IBV vaccine strains at the 1st and 14th day, respectively. Twenty one days after last vaccination, non-vaccinated-challenged group and vaccinated group were challenged using variant 2-like IBV. Serum samples were collected before challenge to measure humoral immune response of chickens. Five days after challenge, the tissue samples from the trachea, lungs and kidneys were taken to evaluate cilliary activity, viral load (quantitative real-time RT-PCR), and histopathological evaluation. Clinical sign scores were also recorded after challenge. Overall, the results showed a protective efficacy of the used vaccination program. Best cross protection (69.2%) was obtained in the H120-1/96 vaccinated group. Virus replication of the challenged virus in H120-1/96 group compared with H120-H120 group showed a significant reduction of viral load in trachea (1.5×103 compared to 503) and kidneys. Clinical sign scores of the challenged groups showed significant effect of the vaccination program to reduce clinical signs. The trachea pathological scores and histopathological findings in the lungs and kidneys also confirmed better protective efficacy of vaccinated groups. In conclusion, using combination of heterologous IBV vaccine serotypes (Massachusetts and 793/B) would be a better strategy to control variant 2-like viruses, but more evaluation is needed using other circulating isolates to find the best combination of vaccines.
禽传染性支气管炎（IB）是一种全球性的鸡病，由禽传染性支气管炎病毒（IBV）引起，该病毒可感染所有商业家禽品系。本研究旨在评估两种不同血清型疫苗（马萨诸塞型和793/B型）的保护作用，以评估针对中东地区流行的IS/1494/06样病毒（2型变异样病毒）攻击的保护效果。将SPF鸡分为四组（n = 20）。第一组和第二组作为阴性对照组和未接种疫苗攻毒组，未接种疫苗。第三组和第四组分别在第1天和第14天接种H120-H120和H120-1/96 IBV疫苗株。最后一次接种疫苗21天后，未接种疫苗攻毒组和接种疫苗组用2型变异样IBV进行攻毒。在攻毒前采集血清样本以检测鸡的体液免疫反应。攻毒后5天，采集气管、肺和肾脏的组织样本，以评估纤毛活性、病毒载量（定量实时RT-PCR）和组织病理学评估。攻毒后还记录临床症状评分。总体而言，结果显示所用疫苗接种方案具有保护效力。在H120-1/96接种组中获得了最佳交叉保护（69.2%）。与H120-H120组相比，H120-1/96组中攻毒病毒的复制显示气管（1.5×103 对比503）和肾脏中的病毒载量显著降低。攻毒组的临床症状评分显示疫苗接种方案对减轻临床症状有显著效果。气管病理评分以及肺和肾脏的组织病理学结果也证实了接种疫苗组具有更好的保护效力。总之，使用异源IBV疫苗血清型（马萨诸塞型和793/B型）组合将是控制2型变异样病毒的更好策略，但需要使用其他流行分离株进行更多评估，以找到最佳疫苗组合。
