Weiss J, Kao L, Victor M, Elsbach P
J Clin Invest. 1985 Jul;76(1):206-12. doi: 10.1172/JCI111947.
Effective killing of bacteria by polymorphonuclear leukocytes (PMN) is generally assumed to require intracellular sequestration and, depending on the bacterial species, can be both O2-dependent or O2-independent. Killing of several strains of Salmonella typhimurium and Escherichia coli by rabbit PMN does not require O2 and is apparently due to a granule-associated bactericidal/permeability-increasing protein (BPI) present in rabbit and human PMN. In this study we examined the O2 dependence of the killing of E. coli (S15) by human PMN. Ingested and noningested E. coli were separated by centrifugation after incubation with PMN in room air or under N2. In the presence of heat-treated serum approximately 50% of E. coli (10 bacteria/PMN) were taken up by PMN and rapidly (5-15 min) killed both in room air and under N2. The remaining extracellular bacteria (approximately 50%) were killed during 30-60 min of incubation in room air but not under N2. When uptake of E. coli by PMN was increased to approximately 80% by the use of C6-depleted serum (retaining heat-labile opsonins), bacterial survival under N2 was reduced from 54 +/- 7.6% to 13 +/- 5.5%. PMN from a patient with chronic granulomatous disease killed PMN-associated but not extracellular E. coli. BPI was detected, by indirect immunofluorescence, on the surface of PMN-associated E. coli within 5 min of incubation of E. coli with PMN both in room air and under N2. In contrast, at no time was BPI detected on the surface of extracellular E. coli, indicating that the non-PMN-associated E. coli had not been previously ingested. Thus, killing of ingested E. coli S15 by human as well as rabbit PMN does not require O2 and appears to be BPI-mediated. However, when ingestion is limited, extracellular bacteria can also be killed but principally by O2-dependent mechanisms.
一般认为，多形核白细胞（PMN）有效杀灭细菌需要将细菌隔离在细胞内，并且根据细菌种类的不同，杀灭过程既可以依赖氧气，也可以不依赖氧气。兔PMN对几种鼠伤寒沙门氏菌和大肠杆菌菌株的杀灭不依赖氧气，这显然是由于兔和人PMN中存在一种与颗粒相关的杀菌/通透性增加蛋白（BPI）。在本研究中，我们检测了人PMN杀灭大肠杆菌（S15）对氧气的依赖性。在室温空气中或氮气环境下，将大肠杆菌与PMN孵育后，通过离心分离摄入和未摄入的大肠杆菌。在存在热处理血清的情况下，约50%的大肠杆菌（10个细菌/PMN）被PMN摄取，并在室温空气和氮气环境下迅速（5 - 15分钟）被杀灭。其余细胞外细菌（约50%）在室温空气中孵育30 - 60分钟后被杀灭，但在氮气环境下未被杀灭。当使用C6缺失血清（保留热不稳定调理素）使大肠杆菌被PMN的摄取增加到约80%时，氮气环境下细菌的存活率从54±7.6%降至13±5.5%。慢性肉芽肿病患者的PMN可杀灭与PMN相关的大肠杆菌，但不能杀灭细胞外的大肠杆菌。通过间接免疫荧光法检测发现，在室温空气和氮气环境下，大肠杆菌与PMN孵育5分钟内，BPI就出现在与PMN相关的大肠杆菌表面。相比之下，在细胞外大肠杆菌表面从未检测到BPI，这表明未与PMN相关联的大肠杆菌之前未被摄取。因此，人及兔PMN杀灭摄入的大肠杆菌S15不依赖氧气，似乎是由BPI介导的。然而，当摄取有限时，细胞外细菌也可以被杀灭，但主要是通过依赖氧气的机制。
