Mouse potency assay for Bordetella bronchiseptica bacterins

Area of Science:

• Veterinary immunology
• Bacteriology
• Animal health

Background:

• Bordetella bronchiseptica causes significant respiratory disease in swine, leading to economic losses.
• Effective bacterins are crucial for controlling B. bronchiseptica infections in swine herds.
• Standardized potency assays are needed to ensure the efficacy of veterinary vaccines.

Purpose of the Study:

• To develop and validate a mouse potency assay for Bordetella bronchiseptica bacterins.
• To assess the immunogenicity of different bacterins using the developed mouse model.
• To correlate mouse assay results with efficacy in swine against Bordetella-induced nasal turbinate atrophy.

Main Methods:

• A mouse model was used to evaluate the ability of bacterins to prevent death following challenge.
• Three bacterins (B, C, D) and a reference standard bacterin (RSB-A) were tested in mice.
• Swine were immunized with RSB-A, bacterins B, and C to assess efficacy against gross nasal turbinate atrophy (GNTA).

Main Results:

• In mice, RSB-A and bacterins B, C, and D provided average survivals of 94%, 88%, 49%, and 32%, respectively.
• Unvaccinated mice had an average mortality rate of 88%.
• In swine, RSB-A reduced GNTA from 85% in controls to 25%. Bacterin B showed 0% GNTA, while bacterin C showed 100% GNTA.

Conclusions:

• The developed mouse potency assay effectively differentiates the protective immunogenicity of Bordetella bronchiseptica bacterins.
• Mouse survival in the assay correlates with the reduction of nasal turbinate atrophy in swine.
• This assay provides a valuable tool for quality control and development of Bordetella bronchiseptica bacterins for swine.