Kinetics of phagocytosis of Staphylococcus aureus and Escherichia coli by human granulocytes.
Kinetics of phagocytosis of Staphylococcus aureus and Escherichia coli by human granulocytes.
复制标题
人粒细胞吞噬金黄色葡萄球菌和大肠杆菌的动力学。
作者：
P. Leijh;M. V. D. Barselaar;T. L. Zwet;I. Dubbeldeman‐Rempt;R. V. Furth
虽然粒细胞对微生物的吞噬是抵抗感染的最重要的防御机制之一，但对这一过程的动力学知之甚少。目前的研究表明，金黄色葡萄球菌和大肠杆菌的摄取率取决于粒细胞和细菌的浓度。细菌与细胞的比例在100:1 ~ 1:10范围内，细菌的吞噬作用在前30分钟呈指数增长。在细菌与细胞的比例为1:1时，对细胞外细菌的生长进行校正后，在前90分钟内摄入的过程呈指数增长。由于发现粒细胞在不同的菌胞比下对细菌的吞噬可以用Michaelis-Menten动力学来描述，所以我们在前30分钟的初始速率基础上研究了吞噬动力学。吞噬率和粒细胞对细菌的最大摄取程度被证明与测定中使用的血清浓度有关。达到最大摄取量所需的最低血清浓度金黄色葡萄球菌为2.5%，大肠杆菌为5%。当细菌被预调理时，预调理的持续时间被证明是限制吞噬率的依赖于血清浓度。温度对微生物的吞噬作用有双重影响。首先，在4到33度的温度下，细胞功能的下降会导致吞噬速率的下降。在42度以上，温度主要影响微生物的调理，对摄入过程只有轻微的影响。根据本研究获得的数据，在37度条件下，在细菌与细胞比例为100:1的条件下，计算出的最大吞噬速率为6.3 × 10(6)个金黄色葡萄球菌/5 × 10(6)个粒细胞/min，计算出的最大吞噬速率为7.1 × 10(6)个大肠杆菌/5 × 10(6)个粒细胞/min，即平均每粒粒细胞每分钟约有1个细菌。计算出的一个粒细胞最大吞噬细菌数在40 ~ 50个之间。
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.