Related Experiment Videos
Characterization of the immunogenicity of formaldehyde detoxified Pasteurella multocida toxin
Abstract:
The immunogenicity of the Pasteurella multocida toxin (PMT) was studied in murine model systems. Mice were vaccinated with either formaldehyde treated pure PMT (pure toxoid) or formaldehyde treated crude extract of toxigenic P. multocida (crude toxoid). The corresponding mean anti-PMT titres, sero-conversion rates and survival rates after challenge with affinity purified PMT were compared. When assessed both by anti-PMT titres and seroconversion and challenge, pure toxoid was a more potent immunogen than crude toxoid. This greater immunogenic potency was unaffected by the addition of killed cell preparations of Bordetella bronchiseptica, non-toxigenic P. multocida and B. pertussis. Increasing anti-PMT titres and seroconversion rates were induced by increasing doses of formaldehyde treated PMT (fPMT) in the pure toxoid vaccines, but not in the vaccines containing crude toxoid. However, improved survival rates were observed for both types of vaccine, when the fPMT content was raised. Immunization of pregnant mice with vaccines containing fPMT induced protection of the offspring against challenge with PMT; the protection of the offspring corresponded to that of the mother.
Insights
Pure Pasteurella multocida toxin (PMT) toxoid demonstrated superior immunogenicity compared to crude toxoid in mice. This finding holds significant implications for developing effective PMT vaccines.
Area of Science:
- Veterinary Immunology
- Bacteriology
Background:
- Pasteurella multocida toxin (PMT) is a key virulence factor.
- Understanding PMT immunogenicity is crucial for vaccine development.
Purpose of the Study:
- To compare the immunogenicity of pure PMT toxoid versus crude toxoid.
- To evaluate the impact of vaccine components and dosage on immune response and protection.
Main Methods:
- Murine models were vaccinated with formaldehyde-treated pure PMT (pure toxoid) or crude P. multocida extract (crude toxoid).
- Immunogenicity was assessed by anti-PMT antibody titers, seroconversion rates, and survival after challenge.
- Dose-response and adjuvant effects were investigated.
Main Results:
- Pure toxoid elicited higher anti-PMT titers and seroconversion rates than crude toxoid.
- Adjuvants did not enhance the potency of pure toxoid.
- Increased formaldehyde-treated PMT (fPMT) dosage improved survival rates for both vaccine types.
- Maternal immunization with fPMT-containing vaccines conferred protection to offspring.
Conclusions:
- Pure PMT toxoid is a more potent immunogen than crude toxoid.
- Vaccine efficacy can be enhanced by increasing fPMT content.
- Maternal vaccination offers a strategy for protecting offspring from PMT challenge.