Genetic diversity of the Campylobacter genes coding immunodominant proteins

Three Campylobacter jejuni 72Dz/92 genes (cjaA (ompH1), cjaC (hisJ) and cja D (omp18)) encoding immunodominant proteins are considered to be potential chicken vaccine candidates. The presence and conservation of cjaA, cjaC and cjaD genes among different Campylobacter clinical isolates were determined . The genes were detected in thirty Campylobacter strains using hybridizati on as well as Western blot analysis. However, PCR products of the predicted size were amplified only from ten out of thirty examined strains regardles s of the employed primer pair. The nucleotide sequence of the C. jejuni 72D z/92 genes was compared with the nucleotide sequences of their homologs clo ned from other Campylobacter strains as well as with the whole genome seque nce of C. jejuni NCTC 11168. The examined sequences revealed 0 to 16% diver gence. Strain-dependent levels of divergence were observed. The polymorphis m detected in cjaC was mainly within the 5' region of the gene, while the n ucleotide substitutions in cjaA and cjaD are distributed uniformly along th e whole genes. Most of the observed nucleotide substitutions occurred at th e third base of the codons. This observation is consistent with the results of Western blot experiments. (C) 2000 Federation of European Microbiologic al Societies. Published by Elsevier Science B.V. All rights reserved.