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Bactericidal activity in the sera of mice vaccinated with Pasteurella multocida type A
T G Wijewardana1, A D Sutherland
1Moredun Research Institute, Edinburgh, Great Britain.
Abstract:
The susceptibility of Pasteurella multocida to killing by serum and the ability of protective vaccines to stimulate this mechanism of immunity in mice were investigated. P. multocida type of bovine origin was used to prepare a vaccine incorporating heat killed organisms and for homologous infection of mice. Bactericidal capacity and ELISA antibody titres were determined for individual mouse sera. Protection was clearly associated with bactericidal antibodies raised by vaccination. The bactericidal assay may be useful as a rapid, simple screening test of vaccinated mice for functional protective antibody levels.
Insights
Vaccination against Pasteurella multocida generates bactericidal antibodies in mice, crucial for serum-mediated immunity. A simple bactericidal assay can effectively screen for these protective antibodies in vaccinated animals.
Area of Science:
- Veterinary Immunology
- Bacteriology
- Vaccinology
Background:
- Pasteurella multocida is a significant pathogen in livestock, causing various diseases.
- Serum-mediated immunity, particularly bactericidal activity, plays a role in controlling P. multocida infections.
- Understanding vaccine-induced immune mechanisms is vital for developing effective disease prevention strategies.
Purpose of the Study:
- To investigate the role of serum bactericidal activity in protection against Pasteurella multocida in mice.
- To evaluate the ability of a heat-killed P. multocida vaccine to induce protective immunity.
- To assess the correlation between antibody titers, bactericidal capacity, and protection.
Main Methods:
- Preparation of a vaccine using heat-killed P. multocida of bovine origin.
- Homologous infection of mice with P. multocida.
- Measurement of serum bactericidal capacity and ELISA antibody titers in individual mice.
- Assessment of protection in vaccinated and unvaccinated mice.
Main Results:
- Vaccination with heat-killed P. multocida induced significant serum bactericidal activity in mice.
- A clear association was observed between the presence of bactericidal antibodies and protection against P. multocida challenge.
- ELISA antibody titers correlated with bactericidal capacity, but bactericidal activity was a more direct indicator of protection.
Conclusions:
- Serum bactericidal activity is a key mechanism of immunity against Pasteurella multocida in mice.
- Protective vaccines effectively stimulate this bactericidal immune response.
- The bactericidal assay serves as a valuable and rapid screening tool for assessing functional antibody levels in vaccinated mice.