Leijh P C, van den Barselaar M T, van Zwet T L, Dubbeldeman-Rempt I, van Furth R
Immunology. 1979 Jun;37(2):453-65.
Although phagocytosis of micro-organisms by granulocytes is one of the most important defence mechanisms against infection, little is known about the kinetics of this process. The present study showed that the rate of ingestion of Staphylococcus aureus and Escherichia coli depends on the concentrations of the granulocytes and bacteria. Phagocytosis of bacteria at a bacteria-to-cell ratio in the range between 100:1 and 1:10 showed an exponential course during the first 30 min. At a bacteria-to-cell ratio of 1:1, application of a correction for the outgrowth of extracellular bacteria gave an exponential course of ingestion over the first 90-min period. Since it was found that the phagocytosis of bacteria by granulocytes at various bacteria-to-cell ratios can be described with Michaelis-Menten kinetics, we studied the kinetics of phagocytosis on the basis of the initial rate for the first 30-min period. The rate of phagocytosis and the maximal degree of ingestion of bacteria by granulocytes proved to be related to the concentration of serum used in the assay. The minimal serum concentration required for maximal ingestion was 2.5% for Staphylococcus aureus and 5% for Escherichia coli. When bacteria were pre-opsonized, the duration of pre-opsonization proved to be limiting for the rate of phagocytosis in dependence on the serum concentration. The effect of temperature on the phagocytosis of micro-organisms proved to be two-fold. First, at temperatures between 4 and 33 degrees a decrease in the functioning of the cells leads to a decrease in the rate of phagocytosis. Above 42 degrees, the temperature affects mainly the opsonization of the micro-organisms and has only a slight influence on the ingestion process. From the data obtained in this study, maximal rates of 6.3 X 10(6) Staphylococcus aureus/5 X 10(6) granulocytes/min and of 7.1 X 10(6) Escherichia coli/5 X 10(6) granulocytes/min were calculated for phagocytosis at a bacteria-to-cell ratio of 100:1 at 37 degrees, i.e. on average about one bacterium per granulocyte per min. The maximum calculated number of bacteria ingested by one granulocyte lies between 40 and 50.
尽管粒细胞对微生物的吞噬作用是抵御感染的最重要防御机制之一，但对这一过程的动力学却知之甚少。本研究表明，金黄色葡萄球菌和大肠杆菌的摄取速率取决于粒细胞和细菌的浓度。在细菌与细胞比例为100:1至1:10的范围内，细菌的吞噬作用在最初30分钟内呈指数过程。在细菌与细胞比例为1:1时，对细胞外细菌生长进行校正后，在最初90分钟内摄取呈指数过程。由于发现在不同细菌与细胞比例下粒细胞对细菌的吞噬作用可用米氏动力学来描述，我们基于最初30分钟的初始速率研究了吞噬作用的动力学。粒细胞的吞噬速率和最大摄取程度被证明与测定中所用血清的浓度有关。金黄色葡萄球菌最大摄取所需的最低血清浓度为2.5%，大肠杆菌为5%。当细菌预先进行调理素化时，预先调理素化的持续时间被证明取决于血清浓度，对吞噬速率起限制作用。温度对微生物吞噬作用的影响是双重的。首先，在4至33摄氏度之间，细胞功能的下降导致吞噬速率降低。高于42摄氏度时，温度主要影响微生物的调理素化，对摄取过程的影响较小。根据本研究获得的数据，在37摄氏度下细菌与细胞比例为100:1时，吞噬作用的最大速率计算为6.3×10⁶金黄色葡萄球菌/5×10⁶粒细胞/分钟和7.1×10⁶大肠杆菌/5×10⁶粒细胞/分钟，即平均每分钟每个粒细胞约吞噬一个细菌。计算得出一个粒细胞摄取细菌的最大数量在40至50之间。
