Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
Am J Pathol. 2014 Jan;184(1):171-83. doi: 10.1016/j.ajpath.2013.10.004. Epub 2013 Nov 6.
Patients infected with highly pathogenic avian influenza A H5N1 viruses (H5N1 HPAIV) show diffuse alveolar damage. However, the temporal progression of tissue damage and repair after viral infection remains poorly defined. Therefore, we assessed the sequential histopathological characteristics of mouse lung after intranasal infection with H5N1 HPAIV or H1N1 2009 pandemic influenza virus (H1N1 pdm). We determined the amount and localization of virus in the lung through IHC staining and in situ hybridization. IHC used antibodies raised against the virus protein and antibodies specific for macrophages, type II pneumocytes, or proliferating cell nuclear antigen. In situ hybridization used RNA probes against both viral RNA and mRNA encoding the nucleoprotein and the hemagglutinin protein. H5N1 HPAIV infection and replication were observed in multiple lung cell types and might result in rapid progression of lung injury. Both type II pneumocytes and macrophages proliferated after H5N1 HPAIV infection. However, the abundant macrophages failed to block the viral attack, and proliferation of type II pneumocytes failed to restore the damaged alveoli. In contrast, mice infected with H1N1 pdm exhibited modest proliferation of type II pneumocytes and macrophages and slight alveolar damage. These results suggest that the virulence of H5N1 HPAIV results from the wide range of cell tropism of the virus, excessive virus replication, and rapid development of diffuse alveolar damage.
感染高致病性禽流感 A H5N1 病毒（H5N1 HPAIV）的患者表现为弥漫性肺泡损伤。然而，病毒感染后组织损伤和修复的时间进程仍未明确。因此，我们评估了 H5N1 HPAIV 或 2009 年甲型 H1N1 流感病毒（H1N1 pdm）经鼻腔感染后小鼠肺的连续组织病理学特征。我们通过免疫组化染色和原位杂交确定了病毒在肺中的含量和定位。免疫组化使用针对病毒蛋白的抗体和针对巨噬细胞、II 型肺泡细胞或增殖细胞核抗原的抗体。原位杂交使用针对病毒 RNA 和编码核蛋白和血凝素蛋白的 mRNA 的 RNA 探针。观察到 H5N1 HPAIV 感染和复制存在于多种肺细胞类型中，可能导致肺损伤迅速进展。H5N1 HPAIV 感染后，II 型肺泡细胞和巨噬细胞均发生增殖。然而，大量巨噬细胞未能阻止病毒攻击，II 型肺泡细胞的增殖未能修复受损的肺泡。相比之下，感染 H1N1 pdm 的小鼠表现出 II 型肺泡细胞和巨噬细胞的适度增殖以及轻微的肺泡损伤。这些结果表明，H5N1 HPAIV 的毒力源于病毒广泛的细胞嗜性、过度的病毒复制以及弥漫性肺泡损伤的快速发展。
