Degradation of microorganisms by phagocytic cells.
Degradation of microorganisms by phagocytic cells.
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DOI：
10.1093/clinids/2.1.106
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Peter Elsbach
中科院分区：
文献类型：
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作者：
Peter Elsbach
通常认为被吞噬细胞吞噬的微生物的命运包括消化和完全降解。这一假设与溶酶体的概念以及吞噬细胞被赋予广泛的、颗粒相关的降解酶设施的证据有关[1-4]。似乎可以合理地得出这样的结论：在伴随吞噬作用的脱粒过程中，颗粒内容物的排出引起了对微生物成分的酶攻击。然而，证据表明，摄入的微生物的分子降解是宿主防御中吞噬细胞功能的一个组成部分是有限的。支持广泛降解的大多数论点是基于细胞与微生物群体在体外混合后不同时间间隔制备的吞噬细胞的薄切片电子显微照片。关于吞噬作用期间和之后微生物降解的生化证据的研究很少发表。事实上，在吞噬细胞-微生物相互作用的整体背景下，关于微生物消化的重要问题尚未得到回答[5]。消化是否必然伴随着摄入的细菌被杀死，或者微生物被膜成分的分解是导致繁殖能力丧失的事件链中的一个必要环节？微生物的消化有多彻底？在处理病原微生物时，微生物成分逃避降解，从而保持抗原刺激，维持宿主的免疫意识，这对宿主有利吗？微生物和吞噬细胞的哪些特性决定消化的程度？微生物自溶酶的调理作用和激活在吞噬细胞降解酶装置的有效性中起什么作用？短寿命的多形核白细胞（PMN）和长寿命的单核巨噬细胞在消化被杀死的微生物时履行不同的和顺序的功能吗？
It is often assumed that the fate of microorganisms that are engulfed by phagocytic cells includes digestion and complete degradation. This supposi-tion is linked both to the lysosome concept and to the demonstration that phagocytes are endowed with an extensive, granule-associated armamentarium of degradative enzymes [1-4]. It appears reasonable to conclude that the discharge of granule contents during the degranulation that accom-panies phagocytosis gives rise to an enzymatic attack on microbial constituents. However, evidence showing that molecular degradation of ingested microorganisms is an integral part of the function of phagocytes in host defense is limited. Most arguments in support of extensive degradation are based upon thin-section electron micrographs of phagocytes prepared at various intervals after the cells were mixed in vitro with populations of micro-organisms. Few studies concerned with biochemical evidence of microbial degradation during and after phagocytosis have been published. In fact, in the overall context of phagocyte-microbe inter-action, important questions about microbial diges-tion have not been answered [5]. Does digestion necessarily follow the killing of ingested bacteria, or is the catabolism of components of the micro-bial envelope a necessary link in the chain of events that culminates in the loss of ability to mul-tiply? How complete is the digestion of microorganisms? In dealing with pathogenic microorganisms, is it to the host's advantage that microbial constituents escape degradation and therefore remain as antigenic stimuli that maintain the host's immunologic awareness? Which properties of mi-croorganisms and of phagocytes determine the ex-tent of digestion? What role do opsonization and activation of microbial autolytic enzymes play in the effectiveness of the phagocyte's degradative enzymatic apparatus? Do the short-lived polymorphonuclear leukocyte (PMN) and the longerlasting mononuclear macrophage fulfill different and sequential functions in the digestion of killed microorganisms?