Binding of bacterial peptidoglycan to CD14
Binding of bacterial peptidoglycan to CD14
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DOI：
10.1074/jbc.273.15.8680
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发表时间：
1998-04-10
影响因子：
4.8
通讯作者：
Tobias, PS
中科院分区：
文献类型：
--
作者：
Dziarski, R;Tapping, RI;Tobias, PS
对可溶性肽聚糖（sPGN，一种来自革兰氏阳性菌的巨噬细胞激活剂）与CD 14（一种脂多糖（LPS）受体）结合的假设进行了测试。在以下三种测定中sPGN特异性结合至CD 14：可溶性P-32-CD 14（sCD 14）与琼脂糖固定的sPGN的结合、酶联免疫吸附测定和光亲和交联。sCD 14还与琼脂糖固定的胞壁酰二肽或GlcNAc-胞壁酰二肽特异性结合，但不与PGN五肽特异性结合。sCD 14与sPGN和ReLPS（其中ReLPS是来自沙门氏菌Re 595的LPS）的结合被未标记的sCD 14、sCD 14的1-152 N末端片段、sPGN、光滑LPS、ReLPS、脂质A和脂磷壁酸竞争性抑制，但不被葡聚糖、硫酸葡聚糖、肝素、核糖醇磷壁酸或可溶性低分子量PGN片段抑制。sCD 14与sPGN的结合比与ReLPS的结合慢，但亲和力更高（KD = 25 nM vs 41 nM）。LPS结合蛋白（LBP）通过增加另一个较低亲和力的K-D和另一个较高的B-max来增加sCD 14与sPGN的结合，但对于ReLPS，LBP通过产生两个具有显著较高亲和力的K-D（7.1和27 nM）来增加结合亲和力。LBP还增强LPS、ReLPS和脂质A对sCD 14结合的抑制。sCD 14与sPGN和ReLPS的结合被抗CD 14 MEM-18 mAb抑制，但其他抗CD 14 mAb显示差异抑制，表明sPGN和LPS在CD 14上的构象结合位点部分相同，部分不同。
The hypothesis that soluble peptidoglycan (sPGN, a macrophage-activator from Gram-positive bacteria) binds to CD14 (a lipopolysaccharide (LPS) receptor) was tested. sPGN specifically bound to CD14 in the following three assays: binding of soluble P-32-CD14 (sCD14) to agarose-immobilized sPGN, enzyme-linked immunosorbent assay, and photoaffinity cross-linking. sCD14 also specifically bound to agarose-immobilized muramyl dipeptide or GlcNAc-muramyl dipeptide but not to PGN pentapeptide. Binding of sCD14 to both sPGN and ReLPS (where ReLPS is LPS from Salmonella minnesota Re 595) was competitively inhibited by unlabeled sCD14, 1-152 N-terminal fragment of sCD14, sPGN, smooth LPS, ReLPS, lipid A, and lipoteichoic acid but not by dextran, dextran sulfate, heparin, ribitol teichoic acid, or soluble low molecular weight PGN fragments. Binding of sCD14 to sPGN was slower than to ReLPS but of higher affinity (K-D = 25 nM versus 41 nM). LPS-binding protein (LBP) increased the binding of sCD14 to sPGN by adding another lower affinity K-D and another higher B-max, but for ReLPS, LBP increased the affinity of binding by yielding two K-D with significantly higher affinity (7.1 and 27 nM). LBP also enhanced inhibition of sCD14 binding by LPS, ReLPS, and lipid A. Binding of sCD14 to both sPGN and ReLPS was inhibited by anti-CD14 MEM-18 mAb, but other anti-CD14 mAbs showed differential inhibition, suggesting conformational binding sites on CD14 for sPGN and LPS, that are partially identical and partially different.