Bérubé L R, Schur M K, Latta R K, Hirama T, McKenzie C R, Jarrell H C
Institute for Biological Sciences, National Research Council Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6, Canada.
Microb Pathog. 1999 Feb;26(2):65-75. doi: 10.1006/mpat.1998.0254.
Nearly 80% of the adherence of several strains of Streptococcus pneumoniae to A549 lung cells was inhibited by dimyristoylphosphatidylcholine (DMPC), as well as by the following mixtures of lipids: DMPC/globoside, DMPC/asialo GM-1 and DMPC/asialo GM-1/globoside liposomes. Control phosphatidylserine liposomes were ineffective at inhibiting bacterial adherence demonstrating the specificity of the interaction between bacteria and liposomes. FITC-labelled bacteria were shown to adhere directly to silica beads coated with DMPC. The proportion of S. pneumoniae bacteria binding to DMPC-coated beads did not exceed 20% of the bacterial population as shown by the binding isotherm. This clearly demonstrates that only a fraction of the bacterial population (a subpopulation) was capable of binding to the beads. The specificity of bacterial binding to DMPC was further demonstrated by surface plasmon resonance. By this latter technique, the affinity between DMPC and bacteria was shown to be high and substantially non-reversible. Finally, we established that in order to be efficient at inhibiting bacterial binding to A549 cells the average liposome diameter must be greater than approximately 200 nm suggesting that a multivalent attachment of the bacterium to a liposome is required for high affinity binding.
近80%的几种肺炎链球菌菌株对A549肺细胞的黏附被二肉豆蔻酰磷脂酰胆碱（DMPC）以及以下脂质混合物所抑制：DMPC/球蛋白、DMPC/去唾液酸GM-1和DMPC/去唾液酸GM-1/球蛋白脂质体。对照磷脂酰丝氨酸脂质体在抑制细菌黏附方面无效，这证明了细菌与脂质体之间相互作用的特异性。荧光素异硫氰酸酯（FITC）标记的细菌被证明可直接黏附于包被有DMPC的硅胶珠。结合等温线显示，与包被有DMPC的珠子结合的肺炎链球菌细菌比例不超过细菌总数的20%。这清楚地表明只有一小部分细菌群体（一个亚群）能够与珠子结合。表面等离子体共振进一步证明了细菌与DMPC结合的特异性。通过后一种技术，显示DMPC与细菌之间的亲和力很高且基本不可逆。最后，我们确定，为了有效抑制细菌与A549细胞的结合，脂质体的平均直径必须大于约200 nm，这表明细菌与脂质体的多价附着是高亲和力结合所必需的。
