Lind S M, Kenne L, Lindberg A A
Department of Clinical Bacteriology, Karolinska Institute, Huddinge Hospital, Sweden.
J Immunol. 1991 Jun 1;146(11):3864-70.
Mouse mAb were produced against the deep rough strains Salmonella minnesota R 595, Salmonella typhimurium SL 1102, and Escherichia coli D21f2 and screened by enzyme immunoassay against LPS of several chemotypes. Five antibodies were selected for their ability to bind to chemotype deep rough (Re) LPS which has two 3-deoxy-D-manno-octulosonic acid (Kdo) residues in its nonreducing end. Structurally verified oligosaccharides isolated from rough LPS and synthetic analogues of Kdo were used in an enzyme immunoassay inhibition test to determine the binding epitopes for the antibodies. According to their specificities, the antibodies could be divided into three groups. For two of the groups, the recognized structure was the alpha-Kdo (2----4) Kdo disaccharide and for one group the alpha-Kdo (2----4) alpha-Kdo beta-D-GlcN (1----6) alpha-D-GlcN tetrasaccharide, representing a partial structure of the Re LPS. Inhibition studies with synthetic analogues of Kdo showed that the anomeric configuration and the free carboxyl group of the Kdo residue are important features for antibody binding. Changes in the C-1 to C-6 region of the Kdo molecule do influence the antibody recognition considerably whereas changes in the exocyclic C-7 to C-8 region are of secondary importance. Calculation of the conformation of the inner core region showed that the alpha-Kdo (2----4) alpha-Kdo (2---- disaccharide was free and accessible in chemotype Re LPS, but that linkage of a L-glycero-D-manno-heptose to O-5 of the subterminal Kdo both changes the conformation of the Kdo-disaccharide and covers it thereby making it less accessible.
制备了针对明尼苏达沙门氏菌R 595、鼠伤寒沙门氏菌SL 1102和大肠杆菌D21f2深粗糙菌株的小鼠单克隆抗体，并通过酶免疫测定法针对几种化学型的脂多糖进行筛选。选择了五种抗体，因其能够结合化学型深粗糙（Re）脂多糖，该脂多糖在其非还原端有两个3-脱氧-D-甘露糖辛酸（Kdo）残基。从粗糙脂多糖中分离出的经结构验证的寡糖和Kdo的合成类似物用于酶免疫测定抑制试验，以确定抗体的结合表位。根据其特异性，这些抗体可分为三组。对于其中两组，识别的结构是α-Kdo（2→4）Kdo二糖，对于一组是α-Kdo（2→4）α-Kdoβ-D-GlcN（1→6）α-D-GlcN四糖，代表Re脂多糖的部分结构。用Kdo的合成类似物进行的抑制研究表明，Kdo残基的异头构型和游离羧基是抗体结合的重要特征。Kdo分子C-1至C-6区域的变化确实会显著影响抗体识别，而环外C-7至C-8区域的变化则次要。内核心区域构象的计算表明，α-Kdo（2→4）α-Kdo（2→）二糖在化学型Re脂多糖中是游离且可及的，但将L-甘油-D-甘露庚糖连接到亚末端Kdo的O-5上，既改变了Kdo-二糖的构象，又将其覆盖，从而使其更难被触及。
