沙门氏菌脂多糖内核结构域的二糖L-α-D-庚糖1→7-L-α-D-庚糖1→可被抗体识别，并且是一种广泛反应性单克隆抗体的表位。

The disaccharide L-alpha-D-heptose1-->7-L-alpha-D-heptose1-->of the inner core domain of Salmonella lipopolysaccharide is accessible to antibody and is the epitope of a broadly reactive monoclonal antibody.

作者信息

Nnalue N A, Lind S M, Lindberg A A

机构信息

Department of Clinical Bacteriology, Karolinska Institute, Huddinge Hospital, Sweden.

出版信息

J Immunol. 1992 Oct 15;149(8):2722-8.

PMID:1383323

Abstract

We generated a panel of mAb containing at least one specificity against each of the known chemotypes of the Salmonella LPS core domain and used them to investigate the accessibility of core determinants in smooth LPS. Most of the mAb were reactive with at the most three chemotypes of the core as determined by enzyme immunoassay and failed to bind smooth LPS or any of the complete cores of E. coli. One mAb, MASC1-MM3 (MM3), reacted with six different Salmonella core chemotypes, the R2 core of Escherichia coli and a variety of smooth LPS. This mAb reacted equally well with live and heat-killed bacteria. It bound to 123 of 126 clinical isolates of Salmonella and 11 of 73 E. coli strains in a dot-immunoblot assay. Typical ladder-like patterns of bands were observed after immunoblotting of this mAb against electrophoretically resolved smooth LPS from the five major serogroups of Salmonella species (A, B, C1, D1, and E). MM3 had no reactivity with BSA conjugates of O-Ag polysaccharides from the above serogroups confirming specificity for a core epitope. Polysaccharides derived from or synthetic saccharides representative of the various chemotypes of Salmonella LPS core were tested as competitive inhibitors of the binding of MM3 to LPS. The results led to a conclusion that MM3 recognizes the structure, L-alpha-D-Heptose1-->7-L-alpha-D-Heptose1-->disaccharide present as a branch in the Ra, Rb1, Rb2, Rb3 and Rc but lacking in the Rd1, Rd2, and Re chemotypes of the Salmonella LPS core. This disaccharide seems free and accessible on the basis of the previously calculated conformations of the Salmonella (Ra) and E. coli complete cores (R1, R2, R3, R4, and K12). It therefore defines or contains an epitope within the inner core subdomain of Salmonella LPS that is accessible to antibody in long-chained LPS and in intact bacteria with complete LPS.

摘要

我们制备了一组单克隆抗体（mAb），这些抗体针对沙门氏菌脂多糖（LPS）核心结构域的每种已知化学型至少具有一种特异性，并使用它们来研究光滑型LPS中核心决定簇的可及性。通过酶免疫测定确定，大多数mAb最多与三种核心化学型发生反应，并且不能结合光滑型LPS或大肠杆菌的任何完整核心。一种单克隆抗体MASC1-MM3（MM3）与六种不同的沙门氏菌核心化学型、大肠杆菌的R2核心以及多种光滑型LPS发生反应。这种mAb与活细菌和热灭活细菌的反应同样良好。在斑点免疫印迹试验中，它与126株沙门氏菌临床分离株中的123株以及73株大肠杆菌菌株中的11株发生结合。用该mAb对来自沙门氏菌属五个主要血清群（A、B、C1、D1和E）的经电泳分离的光滑型LPS进行免疫印迹后，观察到典型的梯状条带模式。MM3与上述血清群的O抗原多糖的牛血清白蛋白（BSA）偶联物无反应，证实其对核心表位具有特异性。测试了源自沙门氏菌LPS核心各种化学型的多糖或代表性合成糖作为MM3与LPS结合的竞争性抑制剂。结果得出结论，MM3识别L-α-D-庚糖1→7-L-α-D-庚糖1→二糖结构，该结构以分支形式存在于沙门氏菌LPS核心的Ra、Rb1、Rb2、Rb3和Rc化学型中，但在Rd1、Rd2和Re化学型中不存在。基于先前计算的沙门氏菌（Ra）和大肠杆菌完整核心（R1、R2、R3、R4和K12）的构象，这种二糖似乎是游离且可及的。因此，它定义了或包含了沙门氏菌LPS内核心亚结构域中的一个表位，该表位在长链LPS和具有完整LPS的完整细菌中可被抗体识别。