Suzuki Tomoko, Chow Chung-Wai, Downey Gregory P
Department of Medicine and Pediatrics, National Jewish Medical and Research Center, Denver, CO, USA.
Int J Biochem Cell Biol. 2008;40(6-7):1348-61. doi: 10.1016/j.biocel.2008.01.003. Epub 2008 Jan 11.
The lung, with its enormous surface area, is literally 'bathed in a sea' of potential toxins that include pathogenic microorganisms, allergens, and pollutants. To preserve homeostasis and protect itself from injury, the lung has evolved intricate defense systems that guard it from these injurious agents. This chapter will focus on the innate component of the immune system that represents the first line of defense against microbial pathogens and pollutants. The innate immune system of the lung is diverse and includes structural cells such as epithelial cells and fibroblasts as well as itinerant leukocytes such as neutrophils, monocytes, and macrophages. Dendritic cells and mast cells, although of hematopoietic origin, are resident in the lung and help sense and orchestrate immune responses in the lung. Cells of the innate immune system secrete various soluble factors that are directly or indirectly microbicidal and/or modulate the inflammatory response. Among these soluble factors, proteinases and anti-proteinases factor prominently and exert both physiological and pathological effects on the function of diverse cell types in the lung. In concert with the adaptive immune system, the innate immune system of the lung is highly effective in combating invading microbial pathogens as evidenced by the rarity with which healthy humans succumb to lung infections.
肺具有巨大的表面积，实际上“浸泡在”潜在毒素的“海洋”中，这些毒素包括病原微生物、过敏原和污染物。为了维持体内平衡并保护自身免受损伤，肺进化出了复杂的防御系统来抵御这些有害因子。本章将重点介绍免疫系统的固有组成部分，它是抵御微生物病原体和污染物的第一道防线。肺的固有免疫系统多种多样，包括上皮细胞和成纤维细胞等结构细胞，以及中性粒细胞、单核细胞和巨噬细胞等游走白细胞。树突状细胞和肥大细胞虽然起源于造血系统，但驻留在肺中，有助于感知和协调肺中的免疫反应。固有免疫系统的细胞分泌各种可溶性因子，这些因子直接或间接具有杀菌作用和/或调节炎症反应。在这些可溶性因子中，蛋白酶和抗蛋白酶起着突出作用，对肺中多种细胞类型的功能产生生理和病理影响。与适应性免疫系统协同作用，肺的固有免疫系统在对抗入侵的微生物病原体方面非常有效，健康人很少患肺部感染就证明了这一点。
