Division of Food Hygiene, Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11 Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Biomed Res Int. 2013;2013:679038. doi: 10.1155/2013/679038. Epub 2013 Nov 7.
Because cholera toxin (CT) is responsible for most of the symptoms induced by Vibrio cholerae infection, detection of CT is critical for diagnosis of the disease. In this study, we constructed an immunochromatographic test strip for detection of CT (CT-IC) with polyclonal antibodies developed against purified recombinant whole CT protein. The detection limit of the CT-IC was 10 ng/mL of purified recombinant CT, and it could detect the CT in culture supernatant of all 15 toxigenic V. cholerae isolates examined, whereas no false-positive signal was detected in all 5 nontoxigenic V. cholerae isolates examined. The specificity of the CT-IC was examined with recombinant heat-labile toxin (LT), which shares high homology with CT, and it was revealed that the minimum detection limit for LT was 100 times higher than that for CT. In addition, lt gene-positive enterotoxigenic Escherichia coli (ETEC) was examined by CT-IC. The false-positive signals were observed in 3 out of 12 ETEC isolates, but these signals were considerably faint. The CT-IC did not develop false-positive signals with all 7 V. parahaemolyticus isolates. These results showed the high specificity of CT-IC and the feasible use of it for the detection and surveillance of toxigenic V. cholerae.
由于霍乱毒素 (CT) 是霍乱弧菌感染引起的大多数症状的主要原因，因此检测 CT 对于疾病的诊断至关重要。在这项研究中，我们使用针对纯化重组全长 CT 蛋白开发的多克隆抗体构建了用于检测 CT 的免疫层析测试条 (CT-IC)。CT-IC 的检测限为 10ng/mL 的纯化重组 CT，它可以检测所有 15 株产毒霍乱弧菌分离株的培养上清液中的 CT，而在所有 5 株非产毒霍乱弧菌分离株中均未检测到假阳性信号。用与 CT 具有高度同源性的重组不耐热毒素 (LT) 检测了 CT-IC 的特异性，结果表明 LT 的最小检测限比 CT 高 100 倍。此外，还通过 CT-IC 检测了 LT 基因阳性肠产毒性大肠杆菌 (ETEC)。在 12 株 ETEC 分离株中，有 3 株出现假阳性信号，但这些信号相当微弱。CT-IC 与所有 7 株副溶血性弧菌分离株均未产生假阳性信号。这些结果表明 CT-IC 具有高度特异性，可用于检测和监测产毒霍乱弧菌。
