Cytopathic effect inhibition assay for canine interferon activity

Area of Science:

• Veterinary Immunology
• Virology
• Cell Biology

Background:

• Canine interferon (IFN) plays a crucial role in antiviral immunity.
• Accurate assays are needed to quantify canine IFN activity for research and therapeutic applications.
• Optimizing cell-based assays is essential for reliable IFN measurements.

Purpose of the Study:

• To investigate and optimize conditions for a cytopathic effect (CPE) inhibition assay for canine interferon (IFN) activity.
• To compare the utility of Madin-Darby canine kidney (MDCK) cells versus canine tumor cell line A72 for canine IFN assays.
• To determine the optimal vesicular stomatitis virus (VSV) strain and cell density for canine IFN assessment.

Main Methods:

• Investigated canine IFN activity using a cytopathic effect (CPE) inhibition assay.
• Utilized Madin-Darby canine kidney (MDCK) cells and canine tumor cell line A72.
• Employed the New Jersey strain of vesicular stomatitis virus (VSV) as the challenge virus.
• Assessed the impact of cell density and viral load on assay sensitivity and reproducibility.

Main Results:

• MDCK cells showed resistance to VSV when confluent, requiring sparse growth for CPE.
• A72 cells demonstrated less dependence on cell density for VSV growth compared to MDCK cells.
• The MDCK-VSV system offered higher IFN sensitivity, while the A72-VSV system provided better reproducibility.
• Optimal conditions were defined for both cell lines regarding cell number and viral titer.

Conclusions:

• The A72-VSV system is recommended for practical canine IFN assays due to its ease of handling and superior reproducibility.
• While MDCK cells offer higher sensitivity, the A72 cell line provides a more reliable platform for routine canine IFN quantification.
• Standardized assay conditions are crucial for accurate and consistent measurement of canine interferon activity.