Haeffner-Cavaillon N, Caroff M, Cavaillon J M
INSERM U28, Hôpital Broussais, Paris, France.
Mol Immunol. 1989 May;26(5):485-94. doi: 10.1016/0161-5890(89)90108-9.
We previously showed the importance of the 3-deoxy-D-manno-2-octulosonic acid (KDO) residue in endotoxins (lipopolysaccharides, LPS) for the induction of the synthesis and release of interleukin-1 (IL-1) by human monocytes. We further investigated the effect of some structural variations within the KDO molecule on IL-1 production induced by LPS. Deamination of Bordetella pertussis LPS, followed by mild anhydrous acidic methanolysis released a hexasaccharide (fragment B'), which had a terminal methyl ketoside KDO residue with a methyl-esterified carboxyl group. This fragment was unable to induce IL-1 production by human monocytes. Fragment B' could be converted into an active hexasaccharide by de-esterification (fragment B-OMe), but not by reduction of the methyl ester group. The KDO residues in the LPS of some bacterial species have been shown to be phosphorylated and we observed that these LPS were weak IL-1 inducers. Phosphorylated KDO present in Vibrio cholerae and B. pertussis LPS respond poorly in the thiobarbiturate assay (specific for KDO). However, if these LPS were dephosphorylated with aqueous hydrofluoric acid (HF) their KDO response in this assay was increased 5.4- to 2.6-fold, respectively. In parallel, the HF-treated LPS were more potent IL-1 inducers than untreated endotoxins. These data confirm that the KDO residue(s) present in all endotoxins play(s) a major role in the signal(s) leading to IL-1 production by human monocytes, and show that IL-1 induction by LPS (1) requires a free carboxyl group in the KDO and (2) is correlated with the degree of substitution of the KDO.
我们先前已表明，内毒素（脂多糖，LPS）中的3-脱氧-D-甘露-2-辛酮糖酸（KDO）残基对于诱导人单核细胞合成和释放白细胞介素-1（IL-1）具有重要意义。我们进一步研究了KDO分子内某些结构变化对LPS诱导的IL-1产生的影响。百日咳博德特氏菌LPS经脱氨处理，随后进行温和的无水酸性甲醇解，释放出一种六糖（片段B'），其具有一个带有甲酯化羧基的末端甲基酮糖苷KDO残基。该片段无法诱导人单核细胞产生IL-1。片段B'可通过去酯化作用转化为活性六糖（片段B-OMe），但不能通过甲酯基团的还原作用实现转化。已证明某些细菌物种的LPS中的KDO残基被磷酸化，并且我们观察到这些LPS是较弱的IL-1诱导剂。存在于霍乱弧菌和百日咳博德特氏菌LPS中的磷酸化KDO在硫代巴比妥酸测定法（对KDO具有特异性）中的反应较差。然而，如果用氢氟酸（HF）水溶液将这些LPS去磷酸化，它们在该测定法中的KDO反应分别增加5.4至2.6倍。同时，经HF处理的LPS比未处理的内毒素更有效地诱导IL-1产生。这些数据证实，所有内毒素中存在的KDO残基在导致人单核细胞产生IL-1的信号中起主要作用，并表明LPS诱导IL-1产生（1）需要KDO中的游离羧基，（2）与KDO的取代程度相关。
