Holmes R K, Twiddy E M
Infect Immun. 1983 Dec;42(3):914-23. doi: 10.1128/iai.42.3.914-923.1983.
Seventeen selected hybridoma cell lines that produced monoclonal antibodies against cholera enterotoxin (CT) were isolated and characterized. All of the monoclonal antibodies contained the kappa light chain; 14 were of the immunoglobulin G1 (IgG1) isotype and 3 were IgG2a. The 17 monoclonal antibodies were divided into a minimum of seven different specificity groups based on their abilities to bind to the following purified test antigens in solid-phase radioimmunoassays: CT, the A and B polypeptides of CT (CT-A and CT-B, respectively), and the heat-labile enterotoxins designated LTh and LTp from Escherichia coli. The binding of these antibodies to the following subunits and fragments of CT was also determined in Western blots: pentameric CT-B, monomeric CT-B, intact CT-A, and the A1 fragment of CT-A. Each of the monoclonal antibodies was tested for neutralization of CT and for precipitation with CT in immunodiffusion tests. Antigenic determinants were identified on CT that were not present either on CT-A or CT-B. One class was unique for CT and another was shared with LTh and LTp. Antibodies directed against these holotoxin-specific determinants had no neutralizing activity. Most of the monoclonal antibodies that reacted strongly with CT-A or CT-B also reacted strongly with CT holotoxin; however, one class of antibody reacted strongly with CT-A but weakly with CT. Among the monoclonal antibodies against CT-A or CT-B, some were specific for CT and others cross-reacted with LTh and LTp or with LTh only. The most potent neutralizing antibodies were against CT-B, and all of our monoclonal antibodies against CT-B had some neutralizing activity. In contrast, only some of the monoclonal antibodies against CT-A had neutralizing activity, and their specific activities were low. We found no direct correlation between the ability of monoclonal antibodies to neutralize CT and to cross-react with LTh or LTp. None of the epitopes recognized by our monoclonal anti-CT antibodies was present on CT-A and CT-B.
分离并鉴定了17株产生抗霍乱肠毒素（CT）单克隆抗体的杂交瘤细胞系。所有单克隆抗体均含有κ轻链；14株为免疫球蛋白G1（IgG1）亚型，3株为IgG2a。根据17种单克隆抗体在固相放射免疫分析中与以下纯化检测抗原结合的能力，将它们至少分为七个不同的特异性组：CT、CT的A和B多肽（分别为CT-A和CT-B）以及大肠杆菌中称为LTh和LTp的不耐热肠毒素。还通过蛋白质印迹法测定了这些抗体与CT的以下亚基和片段的结合：五聚体CT-B、单体CT-B、完整的CT-A以及CT-A的A1片段。在免疫扩散试验中，检测了每种单克隆抗体对CT的中和作用以及与CT的沉淀反应。在CT上鉴定出了CT-A或CT-B上不存在的抗原决定簇。一类是CT特有的，另一类与LTh和LTp共有。针对这些全毒素特异性决定簇的抗体没有中和活性。大多数与CT-A或CT-B强烈反应的单克隆抗体也与CT全毒素强烈反应；然而，一类抗体与CT-A强烈反应但与CT弱反应。在针对CT-A或CT-B的单克隆抗体中，一些对CT具有特异性，而另一些则与LTh和LTp或仅与LTh发生交叉反应。最有效的中和抗体针对CT-B，我们所有针对CT-B的单克隆抗体都具有一定的中和活性。相比之下，只有一些针对CT-A的单克隆抗体具有中和活性，且它们的比活性较低。我们发现单克隆抗体中和CT的能力与与LTh或LTp交叉反应的能力之间没有直接相关性。我们的单克隆抗CT抗体识别的表位在CT-A和CT-B上均不存在。
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