The 26-Killodalton, AhpC homologue, of Helicobacter pylori is also produced by other Helicobacter species

Background. The 26 kDa protein, which is an alkyl hydroperoxide reductase ( AhpC) homologue, has earlier been described as specific for Helicobacter py lori. The aims of this study were to analyse whether this protein, or the c orresponding gene, could be identified in other Helicobacter species. Materials and Methods. Two different monoclonal antibodies (Mabs), which re cognise the 26 kDa protein in H. pylori, were used in immunoblots to determ ine the presence of the protein in 10 Helicobacter species. PCR was perform ed in order to analyse whether the gene was detectable and the PCR products were sequenced. Southern and Northern blot analyses were done on chromosom al DNA and total RNA, respectively, isolated from some selected Helicobacte r species in order to compare the genes and mRNA transcripts to H. pylori. Results. The 26 kDa protein was identified in H. nemestrinae (primate), H. acinonychis (cheetah), H. bills (mouse), H. felis (cat) and H. salomonis (d og) but not in H. mustelae (ferret), H. cinaedi (human), H. canis (dog), H. fennelliae (human) or H. pullorum (poultry). By PCR the gene was also reco gnised in H. mustelae, H. cinaedi and II. pullorum. The PCR products showed high sequence homology (66-98%) compared to H. pylori. The gene was also h ighly conserved in four H. pylori strains (94-99% homology). Southern blot showed that the H, nemestrinae and H. acinonychis chromosomal DNA contained a single copy of the gene and the Northern blot analyses indicated mono-ci stronic transcription of the gene in these two species, as has been found i n H. pylori. Conclusions. A gene similar to ahpC was found in eight out of 10 Helicobact er species analysed.