Hormesis results in trade-offs with immunity

Area of Science:

• Aging and longevity research
• Immunology
• Stress response mechanisms

Background:

• Hormesis proposes that low-level stressors can confer health benefits.
• Previous studies have not clarified if hormetic benefits are cost-free or have trade-offs.
• Understanding these trade-offs is crucial for applying hormesis to human health.

Purpose of the Study:

• To investigate the potential trade-offs between hormesis and immunity.
• To determine if hormetic benefits, such as increased longevity, impact immune function.
• To explore the mechanisms behind stress-induced life-history trade-offs.

Main Methods:

• Utilized the fruit fly, Drosophila melanogaster, as a model organism.
• Administered a single topical dose of dead spores of the fungus Metarhizium robertsii.
• Assessed longevity, fecundity, and immune response to live infections in different fly lines.

Main Results:

• Topical application of dead fungal spores increased fruit fly longevity without significantly reducing fecundity.
• Hormetic benefits were more pronounced in fruit fly lines with compromised antifungal immunity.
• In outbred fly lines, hormesis enhanced survival and fecundity but impaired the ability to combat live infections.

Conclusions:

• Hormesis is associated with trade-offs involving immunity, not cost-free benefits.
• Reduced immune function may be an unintended consequence of hormetic interventions.
• Findings illuminate pathogen-induced life-history trade-offs and the complex relationship between stress and health.