Kroll H P, Bhakdi S, Taylor P W
Infect Immun. 1983 Dec;42(3):1055-66. doi: 10.1128/iai.42.3.1055-1066.1983.
The effect of bactericidal concentrations of lysozyme-free human serum on parameters of membrane integrity has been studied in serum-susceptible and serum-resistant Escherichia coli strains. Serum treatment released all of the alkaline phosphatase from the periplasmic space of two rapidly serum-susceptible strains but did so at different rates. In contrast, no periplasmic enzyme was released from two serum-resistant strains or from one moderately susceptible smooth strain. Lysozyme-free serum and heat-inactivated serum released comparable amounts of 86Rb+ from preloaded cells at comparable rates, regardless of serum susceptibility. Serum decreased the rate of phospholipid biosynthesis in both serum-susceptible and serum-resistant strains. In susceptible but not in resistant strains, intracellular ATP pools were depleted after serum exposure. Outer membranes and cytoplasmic membranes were prepared from serum-treated E. coli, and assays for C3 and C5b-9(m) were performed. With rapidly susceptible strains, C3 deposition on the outer membrane without attachment of C5b-9(m) occurred during the short prekilling phase. Subsequent bacterial killing was accompanied by deposition of C5b-9(m), which was recovered with C3 exclusively in outer membrane fractions with increased density and by eventual total loss of recoverable cytoplasmic membranes. Minimal deposition of complement components, without accompanying cytoplasmic membrane loss, occurred with serum-resistant strains. Loss of recoverable cytoplasmic membrane was not due to the action of either serum or bacterial phospholipase A. The results raise the possibilities that C5b-9(m) primarily damages the outer membrane and that the bacteria themselves actively participate in the ensuing, as yet unclarified, metabolic reactions that finally lead to their death.
已在血清敏感型和血清耐药型大肠杆菌菌株中研究了无溶菌酶人血清杀菌浓度对膜完整性参数的影响。血清处理使两种快速血清敏感型菌株周质空间中的所有碱性磷酸酶释放出来，但释放速率不同。相比之下，两种血清耐药型菌株或一种中度敏感的光滑型菌株均未释放周质酶。无论血清敏感性如何，无溶菌酶血清和热灭活血清以相当的速率从预加载细胞中释放出相当数量的86Rb+。血清降低了血清敏感型和血清耐药型菌株中磷脂生物合成的速率。在敏感菌株而非耐药菌株中，血清暴露后细胞内ATP池被耗尽。从经血清处理的大肠杆菌中制备外膜和细胞质膜，并进行C3和C5b-9(m)检测。对于快速敏感型菌株，在短时间的预杀伤阶段，C3在外膜上沉积但未附着C5b-9(m)。随后的细菌杀伤伴随着C5b-9(m)的沉积，其仅在外膜部分中与C3一起以密度增加的形式回收，并且最终可回收的细胞质膜完全丧失。血清耐药型菌株中补体成分的沉积最少，且没有伴随细胞质膜的丧失。可回收细胞质膜的丧失不是由于血清或细菌磷脂酶A的作用。这些结果提出了以下可能性：C5b-9(m)主要损伤外膜，并且细菌自身积极参与随后尚未阐明的代谢反应，最终导致其死亡。
