Department of Immunobiology, University of Arizona Tucson, Arizona, USA.
Department of Microbiology and Immunology, University of North Carolina at Chapel Hill Chapel Hill, North Carolina, USA.
Immun Inflamm Dis. 2015 Jun;3(2):71-81. doi: 10.1002/iid3.51. Epub 2015 Mar 23.
Alveolar macrophages play a critical role in initiating the immune response to inhaled pathogens and have been shown to be the first cell type infected following intranasal inoculation with several pathogens, including Francisella tularensis. In an attempt to further dissect the role of alveolar macrophages in the immune response to Francisella, we selectively depleted alveolar macrophages using CD11c.DOG mice. CD11c.DOG mice express the diphtheria toxin receptor (DTR) under control of the full CD11c promoter. Because mice do not express DTR, tissue restricted expression of the primate DTR followed by treatment with diphtheria toxin (DT) has been widely used as a tool in immunology to examine the effect of acute depletion of a specific immune subset following normal development. We successfully depleted alveolar macrophages via intranasal administration of DT. However, alveolar macrophage depletion was accompanied by many other changes to the cellular composition and cytokine/chemokine milieu in the lung that potentially impact innate and adaptive immune responses. Importantly, we observed a transient influx of neutrophils in the lung and spleen. Our experience serves as a cautionary note to other researchers using DTR mice given the complex changes that occur following DT treatment that must be taken into account when analyzing data.
肺泡巨噬细胞在启动对吸入病原体的免疫反应中起着关键作用，并且已经表明，在经鼻腔接种几种病原体（包括土拉弗朗西斯菌）后，它们是首先被感染的细胞类型。为了进一步剖析肺泡巨噬细胞在土拉弗朗西斯菌免疫反应中的作用，我们使用 CD11c.DOG 小鼠选择性地耗尽肺泡巨噬细胞。CD11c.DOG 小鼠在完整的 CD11c 启动子的控制下表达白喉毒素受体（DTR）。由于小鼠不表达 DTR，因此在免疫生物学中，已经广泛使用组织限制性表达灵长类 DTR 并随后用白喉毒素（DT）处理，作为一种工具来检查在正常发育后急性耗尽特定免疫亚群对固有和适应性免疫反应的影响。我们通过鼻腔内给予 DT 成功耗尽了肺泡巨噬细胞。然而，肺泡巨噬细胞的耗竭伴随着肺部细胞组成和细胞因子/趋化因子环境的许多其他变化，这些变化可能会影响先天和适应性免疫反应。重要的是，我们观察到肺部和脾脏中的中性粒细胞短暂涌入。我们的经验为使用 DTR 小鼠的其他研究人员敲响了警钟，因为在 DT 处理后会发生复杂的变化，在分析数据时必须考虑这些变化。
