Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt.
Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt.
Dev Biol. 2019 Oct 1;454(1):29-43. doi: 10.1016/j.ydbio.2019.06.013. Epub 2019 Jun 21.
Recently, pulmonary DC deserved the attention of researchers and clinicians as it was implicated in many diseases afflicting human lungs. However, there are no available data about the morphological or functional features of pulmonary dendritic cells in fetal or early neonatal life. The present study aimed to demonstrate the morphological development of DCs using light-, electron-microscopy, and immunohistochemistry. DCs showed strong immunoreactivity for both CD8 and CD56. Moreover, DCs strongly expressed CD34, VEGF, NSE, and connexin-43 within the developing pulmonary tissue. By SEM, DCs were polyhedral in shape with short cell processes in fetal life. By the advancement of the age, DCs became more numerous and exhibited rounded to oval cell bodies with many fine dendrites. TEM revealed that at early fetal life, DCs were characterized by their heterochromatic indented nuclei, few cell processes and few organelles. With the advancement of age, DCs showed dendrite-like processes and displayed signs of high endocytic activities with releasing of secretory materials. At late fetal life, DCs showed an obvious increase in the nuclear/cytoplasmic ratio and they exhibited a unique connection with type II pneumocytes and pulmonary endothelium by gap junction. In the early neonate, the DCs cells were seen in association with T-lymphocytes, neutrophils, telocytes (TCs), and air-blood barrier. They possessed many fine dendrites, the characteristic Birbeck granules and many vesicles. DCs may contribute to apoptosis, endocytosis, and angiogenesis. The difference in the maturation status may reflect different roles for DCs in the lung. The immature DCs may have an antigen-uptake role through endocytosis, while mature DCs may involve in antigen presentation to T-cells.
最近，肺部树突状细胞（DC）引起了研究人员和临床医生的关注，因为它与许多影响人类肺部的疾病有关。然而，关于胎儿或新生儿期肺部树突状细胞的形态或功能特征尚无可用数据。本研究旨在通过光镜、电镜和免疫组织化学来展示 DC 的形态发育。DC 对 CD8 和 CD56 均表现出强烈的免疫反应性。此外，DC 在发育中的肺组织中强烈表达 CD34、VEGF、NSE 和连接蛋白-43。通过 SEM，DC 在胎儿期呈多面体形，细胞突起短。随着年龄的增长，DC 变得更加丰富，并表现出圆形到椭圆形的细胞体，具有许多细树突。TEM 显示，在胎儿早期，DC 的特征是异染色质凹陷核、短细胞突起和少量细胞器。随着年龄的增长，DC 表现出树突样突起，并显示出高内吞作用的迹象，伴随着分泌物质的释放。在胎儿晚期，DC 的核质比明显增加，它们通过缝隙连接与 II 型肺泡细胞和肺内皮细胞表现出独特的连接。在新生儿早期，可见 DC 细胞与 T 淋巴细胞、中性粒细胞、间质细胞（TCs）和气血屏障有关。它们具有许多细树突、特征性的 Birbeck 颗粒和许多小泡。DC 可能有助于细胞凋亡、内吞作用和血管生成。成熟状态的差异可能反映了 DC 在肺部的不同作用。未成熟的 DC 可能通过内吞作用发挥摄取抗原的作用，而成熟的 DC 可能参与将抗原呈递给 T 细胞。
