Kasai N, Arata S, Mashimo J, Okuda K, Aihara Y, Kotani S, Takada H, Shiba T, Kusumoto S, Imoto M
Infect Immun. 1986 Jan;51(1):43-8. doi: 10.1128/iai.51.1.43-48.1986.
A synthetic compound (compound 516), beta(1-6)-linked D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated by (R)-3-hexadecanoyloxytetradecanoyl, (R)-3-hydroxytetradecanoyl, (R)-3-dodecanoyloxytetradecanoyl, and (R)-3-tetradecanoyloxytetradecanoyl groups at positions 2,3,2', and 3', respectively, exhibited in vitro antigenic reactivity of high specificity comparable to that of free lipid A from Salmonella minnesota R595. This was confirmed by an enzyme-linked immunosorbent assay and an enzyme-linked immunosorbent assay inhibition test with monoclonal and conventional antibodies. The results of comparative analysis performed with several synthetic lipid A analogs as well as three monosaccharide derivatives suggested that the complete structure involving both phosphate groups at the C-1 and C-4' positions and the 3-acyloxyacyl groups at the C-2, C-2', and C-3' positions of the glucosamine disaccharide are required for the expression of the serological specificity of Salmonella-type lipid A. This was deduced from the observations that compound 506, a synthetic Escherichia coli-type lipid A which has the same structure as that of compound 516, except that 3-hydroxytetradecanoyl group is substituted for an acyloxyacyl residue at the C-2 position, exhibited significantly reduced antigenic reactivity as compared with compound 516 and that the replacement by the hydrogen atom of the phosphoryl group at the C-1 position or by 3-hydroxytetradecanoyl or tetradecanoyl groups of acyl residues at the 2, 3, 2', and 3' positions of compound 516 results in a marked reduction of reactivity with monoclonal antibodies 5G and 36G. Similar results were obtained by assays with conventional rabbit antibodies, but the structural difference between compounds 516 and 506 could not be distinguished by these polyclonal antibodies. The results of cross-reactions among synthetic analogs with monoclonal antibodies 161M and 1-9M, which have been confirmed to exhibit different serological specificities from the 5G or 36G antibody, also suggested that the nature and linkage of fatty acyl residues as well as the backbone structure of lipid A play an important role in determining serological specificity of the lipid A molecule.
一种合成化合物（化合物516），即β(1-6)-连接的D-葡糖胺二糖1,4'-二磷酸，其在2、3、2'和3'位分别被(R)-3-十六烷酰氧基十四烷酰基、(R)-3-羟基十四烷酰基、(R)-3-十二烷酰氧基十四烷酰基和(R)-3-十四烷酰氧基十四烷酰基酰化，表现出与来自明尼苏达沙门氏菌R595的游离脂质A相当的高特异性体外抗原反应性。这通过酶联免疫吸附测定以及使用单克隆抗体和传统抗体的酶联免疫吸附测定抑制试验得到证实。用几种合成脂质A类似物以及三种单糖衍生物进行的比较分析结果表明，葡糖胺二糖的C-1和C-4'位的两个磷酸基团以及C-2、C-2'和C-3'位的3-酰氧基酰基基团的完整结构是沙门氏菌型脂质A血清学特异性表达所必需的。这是从以下观察结果推断出来的：化合物506是一种合成的大肠杆菌型脂质A，其结构与化合物516相同，只是C-2位的3-羟基十四烷酰基取代了酰氧基酰基残基，与化合物516相比，其抗原反应性显著降低；并且化合物516的C-1位的磷酰基被氢原子取代，或者2、3、2'和3'位的酰基残基被3-羟基十四烷酰基或十四烷酰基取代，导致与单克隆抗体5G和36G的反应性显著降低。用传统兔抗体进行测定也得到了类似结果，但这些多克隆抗体无法区分化合物516和506之间的结构差异。与单克隆抗体161M和1-9M的合成类似物之间的交叉反应结果，已证实它们表现出与5G或36G抗体不同的血清学特异性，这也表明脂肪酰基残基的性质和连接以及脂质A的主链结构在决定脂质A分子的血清学特异性中起重要作用。
