EXPRESSION OF CAMPYLOBACTER-HYOILEI LIPOOLIGOSACCHARIDE (LOS) ANTIGENS IN ESCHERICHIA-COLI

Campylobacter spp. are well recognized as primary pathogens in animals and in people. To isolate and define the genetic regions encoding maj or surface antigens of Campylobacter hyoilei, genomic DNA of the type strain of the species, RMIT-32A, was cloned into a cosmid vector, pLA2 917, in Escherichia coli and the resulting genomic library was screene d using antiserum raised to the parent C. hyoilei strain. Six cosmid c lones were found to express a series of immunoreactive bands in the 15 -25 kDa range. These bands were proteinase K-resistant and were found in the LPS fraction of the cells, suggesting that the recombinant cosm ids expressed C. hyoilei lipo-oligosaccharide (LOS) antigen(s). The mi nimum DNA insert size required for expression of C. hyoilei LOS antige n(s) in E. coli was 11.8 kb. This region was subcloned into the plasmi d vector pBR322. The partial sequencing of the 11.8 kb region showed t hat it contains two ORFs, designated rfbF and rfbP, showing homology w ith the rfbF gene from Serratia marcescens and the rfbP gene from Salm onella typhimurium. Both genes are involved in LPS synthesis. The regi on also contained a sequence homologous to the rfaC gene of E. coli an d Sal. typhimurium which is involved in core oligosaccharide synthesis .