Sugden E A, Samagh B S, Bundle D R, Duncan J R
Infect Immun. 1987 Mar;55(3):762-70. doi: 10.1128/iai.55.3.762-770.1987.
Lipoarabinomannan (LAM) and lipid-free arabinomannan (AM) were prepared from Mycobacterium paratuberculosis. Purification of LAM was done by ultracentrifugation of the phenol-water-extracted crude polysaccharide, followed by affinity and anion exchange chromatography. AM was purified from the supernatant of the ultracentrifuged polysaccharide or from alkaline-extracted material by gel filtration and anion exchange chromatography. Chemical analysis revealed arabinose and mannose in LAM (1.4:1) and AM (3.5:1) and the presence of palmitic, stearic, and tuberculostearic acids for a total of 7.8% lipid in LAM. Traces of phosphorus were found in the AMs, particularly LAM (0.05%). Nuclear magnetic resonance confirmed the presence of alpha-arabinosyl residues and the acylated nature of LAM. LAM exhibited lipid-dependent aggregation, as indicated by a Triton-induced decrease in molecular weight. By using bovine sera, LAM was found to be active in the complement fixation test, whereas AM was inactive and inhibited this activity. Thus, the presence of AM in crude polysaccharide could explain the variable complement fixation results. Triton-dissociated LAM exhibited a precipitin (Cl) in common with that of AM, confirming shared determinants. LAM in its lipid-dependent aggregated form, however, exhibited a second precipitin (C2), which may be due to the disparity in antigen size or a novel epitope. The lipid content of LAM rendered it 100 times more effective for coating plates in the enzyme immunoassay than lipid-free AM.
脂阿拉伯甘露聚糖（LAM）和去脂阿拉伯甘露聚糖（AM）是从副结核分枝杆菌中制备的。LAM的纯化是通过对苯酚-水提取的粗多糖进行超速离心，然后进行亲和色谱和阴离子交换色谱。AM是从超速离心多糖的上清液或碱性提取物中通过凝胶过滤和阴离子交换色谱纯化的。化学分析表明，LAM中阿拉伯糖和甘露糖的比例为1.4:1，AM中为3.5:1，LAM中棕榈酸、硬脂酸和结核硬脂酸的总量为7.8%。在AMs中发现了微量的磷，特别是LAM（0.05%）。核磁共振证实了α-阿拉伯糖基残基的存在以及LAM的酰化性质。LAM表现出脂质依赖性聚集，如Triton诱导的分子量降低所示。使用牛血清时，发现LAM在补体结合试验中具有活性，而AM无活性并抑制该活性。因此，粗多糖中AM的存在可以解释补体结合试验结果的差异。Triton解离的LAM与AM表现出共同的沉淀素（Cl），证实了共有决定簇。然而，脂质依赖性聚集形式的LAM表现出第二种沉淀素（C2），这可能是由于抗原大小的差异或新的表位。LAM的脂质含量使其在酶免疫测定中包被板的效果比去脂AM高100倍。
