Szalo I M, Taminiau B, Goffaux F, Pirson V, McCappin J, Ball H J, Mainil J G
Bactériologie et Pathologie Bactérienne, Faculté de Médecine Vétérinaire, Université de Liège, Campus du Sart Tilman, Liège B4000, Belgium.
Clin Diagn Lab Immunol. 2004 May;11(3):532-7. doi: 10.1128/CDLI.11.3.532-537.2004.
Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and effacement. They are involved in enteric diseases both in humans and in animals, and EHEC strains can be responsible for hemolytic uremic syndrome in humans. Previously, it was shown that the 2F3 monoclonal antibody (MAb) is specific for the O26 EHEC and EPEC strains (P. Kerr, H. Ball, B. China, J. Mainil, D. Finlay, D. Pollock, I. Wilson, and D. Mackie, Clin. Diagn. Lab. Immunol. 6:610-614, 1999). As these groups of bacteria play an important role in pathology, the aim of this paper was to characterize the antigen recognized by the 2F3 MAb and its genetic determinant. A genomic locus containing the entire O-antigen gene cluster and half of the colanic acid gene cluster from an O26 EHEC strain was shown to be sufficient for the production of the antigen recognized by the 2F3 MAb in an E. coli DH5alpha strain. By transposon mutagenesis performed on the recombinant plasmid, all 2F3 enzyme-linked immunosorbent assay-negative mutants had their transposons inserted into the O-antigen gene cluster. The O-antigen gene cluster was also cloned from an O26 EHEC strain into the E. coli DH5alpha strain, which then produced a positive result with the 2F3 MAb. Further analysis of the type of lipopolysaccharides (smooth or rough) produced by the clones and mutants and of the O antigen of the 2F3-positive clones confirmed that the epitope recognized by the 2F3 MAb is located on the O antigen in the O26 EHEC and EPEC strains and that its genetic determinant is located inside the O-antigen gene cluster.
肠出血性大肠杆菌（EHEC）和肠致病性大肠杆菌（EPEC）是致病性菌株群，其感染的特征是肠上皮细胞附着和脱落的典型病变。它们可导致人类和动物的肠道疾病，并且EHEC菌株可引起人类溶血尿毒综合征。此前研究表明，2F3单克隆抗体（MAb）对O26 EHEC和EPEC菌株具有特异性（P. Kerr、H. Ball、B. China、J. Mainil、D. Finlay、D. Pollock、I. Wilson和D. Mackie，《临床诊断实验室免疫学》6:610 - 614，1999年）。由于这些细菌群在病理学中起着重要作用，本文的目的是鉴定2F3 MAb识别的抗原及其遗传决定因素。结果显示，来自一株O26 EHEC菌株的包含完整O抗原基因簇和一半结肠酸基因簇的基因组位点足以在大肠杆菌DH5α菌株中产生被2F3 MAb识别的抗原。通过对重组质粒进行转座子诱变，所有2F3酶联免疫吸附测定阴性突变体的转座子均插入到O抗原基因簇中。O抗原基因簇也从一株O26 EHEC菌株克隆到大肠杆菌DH5α菌株中，该菌株随后与2F3 MAb产生阳性反应。对克隆体和突变体产生的脂多糖类型（光滑型或粗糙型）以及2F3阳性克隆体的O抗原进行进一步分析，证实2F3 MAb识别的表位位于O26 EHEC和EPEC菌株的O抗原上，并且其遗传决定因素位于O抗原基因簇内。
