Complement-mediated lipopolysaccharide release and outer membrane damage in Escherichia coli J5:: requirement for C9
Complement-mediated lipopolysaccharide release and outer membrane damage in Escherichia coli J5:: requirement for C9
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DOI：
10.1046/j.1365-2567.2001.01198.x
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发表时间：
2001-03-01
期刊：
影响因子：
6.4
通讯作者：
Orren, A
中科院分区：
文献类型：
--
作者：
O'Hara, AM;Moran, AP;Orren, A
脂多糖（LPS）是革兰氏阴性菌外膜的主要抗原成分，可以刺激补体系统的活化。这种激活导致细胞壁上的补体膜攻击复合物（MAC）形成，LPS释放，在血清敏感菌株中导致细胞死亡。在本研究中，大肠杆菌J5菌株。将外源半乳糖单独掺入LPS中，生成具有不同LPS化学型的目标菌株，并用氚（H-3-LPS）标记菌株的LPS。随后监测正常人血清（NHS）和人补体缺陷血清释放LPS的能力。nhss诱导的H-3-LPS在30 min内释放率为64-95.7%。总体而言，不同LPS化学型大肠杆菌J5菌株的LPS释放量无显著差异。在功能分析中，最大LPS释放发生在30min和最大细菌杀灭之前。电镜显示nhs诱导的外膜破坏在15分钟的水泡形式；在这个时间点，内膜保持完整。背景：热灭活血清和缺乏C6、C7、C8的人血清均无LPS释放，且无杀菌活性。c9缺陷（C9D）血清杀菌活性低，不能诱导LPS释放；然而，添加纯化的人C9重建了其释放LPS的能力。该研究表明，在血清敏感的大肠杆菌J5菌株中，需要功能性C9分子来释放lps。
Lipopolysaccharides (LPS) are major antigenic components of the outer membrane of Gramnegative bacteria and can stimulate activation of the complement system. Such activation leads to formation of the complement membrane attack complex (MAC) on the cell walls, LPS release and, in serum-sensitive strains, to cell death. In this study, Escherichia coli J5 strains. which incorporate exogenous galactose exclusively into LPS, were used to generate target strains with different LPS chemotypes, and the LPS of the strains was labelled with tritium (H-3-LPS). The ability of normal human serum (NHS and human complement-deficient sera to release LPS was subsequently monitored. NHS-induced release of 64-95.7% of H-3-LPS within 30 min. overall, no significant difference was observed between release of LPS from E. coli J5 strains with different LPS chemotypes. In Functional assays, maximum LPS release had occurred by 30 min and before maximum bacterial killing. Electron microscopy revealed NHS-induced outer-membrane disruption in the form of blebs at 15 min; at this time-point the inner membrane remained intact. Background LPS release and no bactericidal activity were detected in heat-inactivated serum or human sera deficient in C6, C7 or C8. The C9-deficient (C9D) serum had low bactericidal activity and failed to induce LPS release; however, addition of purified human C9 reconstituted its ability to release LPS. This study demonstrated the need for Functional C9 molecules for LPS-releasing activities in serum-sensitive E. coli J5 strains.