Boyton Rosemary J, Openshaw Peter J
National Heart and Lung Institute at St Mary's Hospital, Imperial College School of Medicine, London, UK.
Br Med Bull. 2002;61:1-12. doi: 10.1093/bmb/61.1.1.
Of all sites in the body, the lung is perhaps challenged by the greatest onslaught of microbial pathogens, many of which would cause lethal infections if unopposed. The immune response to respiratory infection must, therefore, be rapid and efficient. However, the respiratory tract is a fragile tissue with architecture that is finely designed for gas exchange, so that the price of excessive or inappropriate inflammatory responses may itself be very high. The first line of defence comes from barriers such as mucus and cilia, followed by a battery of mediators that constitute the innate response. These include lactoferrin, lysozyme, collectins and defensins. Activation of these molecules can lead directly to lysis of pathogens, or to destruction through opsonisation or the recruitment of inflammatory cells. The adaptive immune response includes the production of neutralising antibodies and the responses of T lymphocytes. Different populations of T lymphocytes may dramatically alter the balance between clearance of the pathogen and induction of tissue damage depending on the cytokines they secrete.
在人体的所有部位中，肺部可能面临着微生物病原体的最大冲击，如果不加以抵抗，其中许多病原体都会导致致命感染。因此，对呼吸道感染的免疫反应必须迅速且有效。然而，呼吸道是一个脆弱的组织，其结构经过精心设计以进行气体交换，所以过度或不适当的炎症反应本身的代价可能非常高昂。第一道防线来自黏液和纤毛等屏障，随后是构成固有免疫反应的一系列介质。这些介质包括乳铁蛋白、溶菌酶、凝集素和防御素。这些分子的激活可直接导致病原体裂解，或通过调理作用或招募炎症细胞来实现破坏。适应性免疫反应包括中和抗体的产生以及T淋巴细胞的反应。不同群体的T淋巴细胞根据它们分泌的细胞因子，可能会显著改变病原体清除与组织损伤诱导之间的平衡。
