Central Veterinary Institute, PO box 65, 8219 PH Lelystad, The Netherlands.
Vet Res. 2011 Jan 18;42(1):10. doi: 10.1186/1297-9716-42-10.
Avian influenza virus can be divided into two groups, highly pathogenic avian influenza virus (HPAI) and low pathogenic avian influenza virus (LPAI) based on their difference in virulence. To investigate if the difference in clinical outcome between LPAI and HPAI in chickens is due to immunological host responses in the lung within the first 24 hours post infection (hpi), chickens were infected with LPAI or HPAI of subtype H7N1. Virus was found in the caudal and cranial part of the lung. With LPAI, virus was localised around the intrapulmonary bronchus and secondary bronchi. In sharp contrast, HPAI was detected throughout the whole lung. However, based on viral RNA levels, no quantitative difference was observed between LPAI and HPAI infected birds. In infected areas of the lungs, an influx of CD8α+ cells as well as KUL01+ macrophages and dendritic cells (DC) occurred as fast as 8 hpi in both infected groups. No major difference between LPAI and HPAI infected birds in the induction of cytokines and interferons at mRNA level in lung tissue was found.In conclusion, the differences in lethality for chickens infected with LPAI or HPAI could be ascribed to difference in location of the virus. However similar amounts of viral RNA, similar cytokine mRNA levels, and similar influxes of CD8α+ and KUL01+ macrophages and DC were found between HPAI and LPAI in the lungs. A cytokine storm at mRNA level as described for mammals was not observed in the lungs of HPAI infected birds within 24 hpi.
根据毒力的不同，禽流感病毒可分为高致病性禽流感病毒（HPAI）和低致病性禽流感病毒（LPAI）。为了研究鸡感染低致病性禽流感病毒（LPAI）和高致病性禽流感病毒（HPAI）后，24 小时内肺部的免疫宿主反应是否导致临床结果的差异，将鸡感染 H7N1 亚型的 LPAI 或 HPAI。在尾部和头部肺部均可检测到病毒。对于 LPAI，病毒主要定位于肺内支气管和次级支气管周围。相比之下，HPAI 可在整个肺部检测到。然而，根据病毒 RNA 水平，感染 LPAI 和 HPAI 的鸟类之间没有观察到定量差异。在肺部感染区域，CD8α+细胞以及 KUL01+巨噬细胞和树突状细胞（DC）在感染后 8 小时内快速流入肺部。在感染的鸟类肺部组织中，未发现 LPAI 和 HPAI 诱导的细胞因子和干扰素在 mRNA 水平上存在明显差异。总之，鸡感染 LPAI 或 HPAI 的致死率差异可能归因于病毒的定位不同。然而，在肺部中，HPAI 和 LPAI 之间的病毒 RNA 量、细胞因子 mRNA 水平以及 CD8α+和 KUL01+巨噬细胞和 DC 的流入量相似。在 24 小时内，未观察到 HPAI 感染鸟类肺部描述的细胞因子风暴。
