Molecular cloning and expression of a gene for outer membrane protein H in Pasteurella multocida (A:3): Production of antisera against the OmpH

Pasteurella multocida is known to cause widespread infections in husbandry. To induce homologous and heterologous immunity against the infections, outer membrane proteins (OMPs) in the envelope of P. multocida are thought to be attractive vaccine candidates. Outer membrane protein II is considered as the major component of OMPs. In this study, a gene for OmpH was isolated from pathogenic P. multocida serogroup A. The gene was composed of 1,047 nucleotides coding 348 amino acids with signal peptide of 20 amino acids. The amino acid composition showed about 80 to 98 per cent sequence homologies among other 10 strains of P. multocida serogroup A, reported so far. A recombinant ompH, from which signal peptide was truncated, was generated using pRSET A to name "pRSET A/OmpH-F2". The pRSET A/OmpH-F2 was well expressed in E. coli BL21(DE3). The truncated OmpH was purified using nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. Its molecular weight was registered to be 40 kDa on SDS-PAGE gel. In order to generate immunesera against the OmpH, 50 ug of the protein was intraperitoneally injected into mice three times. The anti-OmpH immuneserum recognized about 5x10~2 ng quantity of the purified OmpH. It can be used for an effective vaccine production to prevent fowl cholera caused by pathogenic P. multocida (Serogroup A).