[Cloning of a cluster of genes encoding coli-surface antigen 6(CS6) of human enterotoxigenic E. coli].

A gene library was constructed from large plasmid DNA of wild strain E519/66A of human enterotoxigenic Escherichia coli (ETEC). Positive colonies containing CS6 antigen were obtained. The CS6 gene fragment was identified by restriction endonuclease mapping. It was approximately 4.6 kb in length and responsible for encoding CS6 genes and regulating the CS6 antigen. Two forms of fimbriae protein with different molecular weight were produced by the selected clones. Both of them could react with the same CS6 antiserum. So we expect to use the recombinant strain as candidate for human ETEC vaccine development, and it is also useful for further research on the expression and regulation of genes encoding CS6 fimbriae protein.