Quantifying and comparing constitutive immunity across avian species

Area of Science:

• Ecological immunology
• Comparative immunology
• Physiological ecology

Background:

• Ecological immunology is an emerging field integrating immunology and physiological ecology.
• A standardized set of assays for comparative immunology is currently lacking.
• Existing assays often require species-specific reagents, limiting broad application.

Purpose of the Study:

• To develop and validate a panel of innate immunity assays suitable for comparative immunology studies.
• To optimize these assays for use in small birds with limited sample volumes.
• To assess the utility of these assays in multi-species comparisons and under varying physiological conditions.

Main Methods:

• Description of bactericidal assays measuring whole blood's microbial killing capacity.
• Description of phagocytosis assays assessing macrophage phagocytic capacity in whole blood.
• Bioassays for mannan-binding protein and lysozyme to measure plasma acute-phase proteins.

Main Results:

• Assays demonstrated species differences in bactericidal and phagocytic activities in various bird populations.
• Stressed birds (clay-colored thrushes) exhibited reduced phagocytic and antibacterial activities.
• Lipopolysaccharide challenge elevated mannan-binding protein, lysozyme, and haptoglobin, altering blood immune activities.

Conclusions:

• The developed assays are species-independent and suitable for comparative immunology.
• These assays are sensitive to animal stress and infection status.
• The assays require minimal blood volumes (10 microL), making them valuable for field studies in comparative immunity.