Abstract: In order to search the common antigen of out membrane protein of pathogenic Aeromonas isolated from diseased eels, 17 Aeromonas gene sequences of outer membrane protein（OMP）from the NCBI/GenBank were compared and the conserved fragments of one OMP（porin II）were determined. According to the whole genome sequences of Aeromonas hydrophila and Aeromonas salmonicida, the full-length gene sequences of porin II（ompII）were ascertained and the related up and down fragments out of ompII sequences were ascertained. One pair of specific primers was designed at the up and down fragments. Using the primers, 11 OmpII genes were successfully amplified by temperate DNA of 30 strains of pathogenic Aeromonas, and 10 of 11 products were sequenced. Protein structure, hydrophilicity and epitope were analyzed using the predicted expression products of a full-length sequence of ompII. The results showed that the predicted protein was a trans-membrane protein with tertiary structure, and it was also a hydrophilic protein with multiple epitopes. The study provided theoretical basis on gene engineering vaccine designing through common antigens of OMP of pathogenic Aeromonas isolated from farming eels.

Key words: Outer membrane protein, Pathogenic, Aeromonas, Full-length gene cloning, Common epitopes, Eel