Optimization and validation of ELISAs for interferon-gamma determination in bison

Area of Science:

• Wildlife disease ecology
• Immunodiagnostics
• Conservation medicine

Background:

• Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a significant threat to wood bison conservation in Canada.
• Early detection of M. bovis is vital to prevent transmission and protect this culturally and ecologically important species.
• Interferon-gamma (IFNγ) assays are established diagnostic tools for bTB in cattle and other wildlife.

Purpose of the Study:

• To optimize and partially validate two commercial IFNγ ELISA kits for detecting endogenous bison IFNγ.
• To assess the diagnostic potential of these assays in wood bison populations.

Main Methods:

• Evaluation of antibody identification, matrix effects, dilution linearity, and assay reproducibility.
• Optimization of two commercial IFNγ ELISA kits (Mabtech bovine Flex and Pro).
• Testing of mitogen-stimulated whole blood samples from bison.

Main Results:

• Optimized assays showed linear responses to recombinant bovine and endogenous bison IFNγ (1-125 pg/mL; R²=0.99).
• Assays exhibited good recovery and fair reproducibility with a low limit of quantification (1 pg/mL).
• Both Mabtech Flex and Pro kits were deemed suitable for measuring bison IFNγ.

Conclusions:

• Commercial IFNγ ELISA kits can be effectively optimized for diagnosing M. bovis infection in wood bison.
• These validated assays offer a flexible tool for early detection and management of bovine tuberculosis in bison populations.
• Improved diagnostic capabilities are essential for the conservation of wood bison and mitigating zoonotic risks.