Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany.
Am J Pathol. 2011 Aug;179(2):603-9. doi: 10.1016/j.ajpath.2011.04.039. Epub 2011 Jun 25.
Airway mucosal dendritic cells (DCs), located beneath the epithelium of the conducting airways, are believed to be specialized for immunosurveillance via sampling of antigens from the airway luminal surface. However, the dynamics of airway DC activity has not yet been visualized. We used two-photon microscopy to illuminate the endogenous mucosal DC network in the airways of mice. To characterize DC behavior, we used lung section preparations and an intravital microscopic approach. DCs displayed a heterogeneous movement pattern according to their localization within the airway mucosa: sessile intraepithelial DCs with a dendritiform shape exhibited active probing movements and occasionally formed transepithelial extensions into the airway lumen. In contrast, DCs within the deeper layers of the mucosal tissue migrated fast in an amoeboid manner, without probing movements, and slowed down after aeroallergen challenge. Strikingly, neither of these two mucosal DC populations ingested fluorescently labeled antigens after antigen administration to the airways in the steady state, in contrast to alveolar macrophage/DC populations in the lung periphery. Our results provide a first description of the dynamic behavior of airway mucosal DCs, with their exact role in antigen sampling remaining unclear.
气道黏膜树突状细胞（DCs）位于传导气道的上皮下方，被认为通过从气道腔表面采样抗原来专门进行免疫监视。然而，气道 DC 活性的动态变化尚未得到可视化。我们使用双光子显微镜来照亮小鼠气道中的内源性黏膜 DC 网络。为了表征 DC 的行为，我们使用了肺切片制备和活体显微镜方法。根据其在气道黏膜中的定位，DC 显示出异质的运动模式：具有树突状形状的固定上皮内 DC 表现出活跃的探测运动，偶尔会形成穿过上皮的延伸进入气道腔。相比之下，黏膜组织深层的 DC 以阿米巴样方式快速迁移，没有探测运动，并且在变应原攻击后速度减慢。引人注目的是，在稳态下向气道给予荧光标记的抗原后，这两种黏膜 DC 群都没有摄取抗原，而肺泡巨噬细胞/DC 群在肺外周则可以摄取。我们的研究结果首次描述了气道黏膜 DC 的动态行为，但其在抗原采样中的确切作用尚不清楚。
