• Korean Journal of Veterinary Research
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• v.47 no.1
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• pp.59-65
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• 2007

Pasteurella multocida Pasteurella multocida toxin (PMT) is a causal pathogenin atrophic rhinitis in pigs. To investigate the protective immunity and vaccination effect of recombinantPMT, the gene for PMT was isolated from the infective P. multocida D:4. The 2.3 kb XhoI/PstI fragment(PMT2.3) of PMT gene was expressed in E. coli BL21 (DE3) using the induced expression vector system.The recombinant protein of PMT2.3 having molecular weight of 84 kDa was purified by Ni-afinitycolumn chromatography. The PMT2.3 raised slightly less anti-PMT antibody titer than formalin-killedwhole cel, however, it showed more protective imunity against P. multocida D:4 infection in vaccinationand chalenge.

• Journal of Microbiology
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• v.44 no.3
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• pp.320-326
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• 2006

Pasteurella multocida is an important veterinary and opportunistic human pathogen. In particular, strains of P. multocida serogroup D cause progressive atrophic rhinitis, and produce a potent, intracellular, mitogenic toxin known as P. multocida toxin (PMT), which is encoded by the toxA gene. To further investigate the toxigenic and pathogenic effects of PMT, a toxA-deleted mutant was developed by homologous gene recombination. When administrated to mice, the toxigenicity of the toxA mutant P. multocida was drastically reduced, suggesting that the PMT constributes the major part of the toxigenicity of P, multocida. Similar results were obtained in a subsequent experiment, while high mortalities were observed when toxA(+) P. multocida bacterial culture or culture Iysate were administrated. Mice immunized with toxA(-) P. multocida were not protected (none survived) following challenge with toxA(+) P. multocida or bacterial culture Iysate (toxin). These results suggest that the toxigenicity of P. multocida is mainly derived from PMT.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1756-1763
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• 2010

Pasteurella multocida serogroup D strain, which produces P. multocida toxin (PMT), is a widespread and harmful pathogen of respiratory diseases such as pneumonia and progressive atrophic rhinitis (PAR) in swine. Vaccination has been considered the most desirable and effective approach for controlling the diseases caused by toxigenic P. multocida. To investigate the antigenicity and immunogenicity of partial fragments of recombinant PMT, recombinant proteins of the N-terminal (PMT-A), middle (PMT-B), C-terminal (PMT-C), and middle-C-terminal (PMT2.3) regions of PMT were successfully produced in an Escherichia coli expression system. The molecular masses of PMT-A, PMT-B, PMT-C, and PMT2.3 were ca. 53, 55, 35, and 84 kDa, respectively, purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. All the recombinant proteins except for PMT-A showed immune responses to antisera obtained from a swine showing symptoms of PAR. Moreover, high titers of PMT-specific antibodies were raised from mice immunized with each of the recombinant proteins; however, the immunoreactivities of the antibodies to authentic PMT and heat-inactivated whole bacteria were different, respectively. In the protection study, the highest protection against homologous challenge was shown in the case of PMT2.3; relatively poor protections occurred for the other PMT fragments.

• Journal of Microbiology
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• v.45 no.4
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• pp.364-366
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• 2007

The immunological role of the Pasteurella multocida toxin (PMT) in mice was examined using a PMT mutant strain. After a nasal inoculation, the mutant strain failed to induce interstitial pneumonia. Moreover, PMT had no significant effect on the populations of CD4+, CD8+, CD3+, and CD19+ immunocytes in blood or on the populations of CD4+ and CD8+ splenocytes (P<0.01). However, there was a significant increase in the total number of cells in the BAL samples obtained from the wild-type P. multocida-inoculated mice. On the other hand, the level of IL-l expression decreased when the macrophages from the bronchio-alveolar lavage were stimulated with PMT. Overall, PMT appears to play some role (stimulating and/or inhibiting) in the immunological responses but further studies will be required to confirm this.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.53-60
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• 2008

We have investigated efficiency of a recombinant subunit Pasteurella multocida toxin (PMT) that was mixed with a vaccine consisted of inactivated whole cells of Bordetella bronchiseptica, P. multocida (types A and D). For verification of the efficacy of the vaccine, all experimental pigs (suckling piglets, sow and gilts) in the three farms were vaccinated. Antibody titers against B. bronchiseptica and P. multocida type A of the vaccinated pigs by microplate agglutination were significantly higher than those of the control pigs (p < 0.05). Similar patterns were observed in the analysis of anti- PMT neutralizing antibody by serum neutralizing method using Vero cell (p < 0.05). Anti- P. multocida type D antibody titer of the vaccinated sows and gilts by ELISA showed significant differences with those of the non-vaccinated pigs (p < 0.05). Although antibody titers increased, it was unable to find out the difference in the clinical signs between the vaccinated and non-vaccinated pigs. However, the increase in body weight of the vaccinated piglets was observed in comparison with the non-vaccinated piglets on a farm. At slaughtering of the pigs, pathological lesions in the turbinate bones of the vaccinated pigs were significantly lower than those of the non-vaccinated pigs (p < 0.001). These results suggested that efficacy of the vaccine in pigs demonstrated to protect against atrophic rhinitis in Korea.

• Korean Journal of Veterinary Service
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• v.33 no.2
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• pp.173-176
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• 2010

Here, we report the suitability of using a resin-type chitosan formulae as a sustained-releasing form adjuvant in comparison with commercially well-known Freund's adjuvants. To induce the immunological responses, N-terminal region of Pasteurella multocida toxin was used as an antigen, which was found to be protective immunogen against P. multocida infection. Mice immunized with chitosan resin formulae showed statistically significant antibody induction (P<0.001) as much as that of Freund’s adjuvants. As a result, the resin-type sustained-releasing form chitosan formulae is thought to be a good candidate for a new type adjuvant.