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Basal superoxide as a sex-specific immune constraint
Michael Tobler1, Mo Healey, Mark Wilson
1School of Biological Sciences, The University of Sydney, Sydney, New South Wales, Australia. michael.tobler@biol.lu.se
Biology Letters
|June 3, 2011
Summary
Systemic reactive oxygen species (ROS) constrain immune activation in male painted dragon lizards. Higher pre-challenge superoxide levels correlate with weaker immune responses, suggesting sex-specific trade-offs in immune investment.
Area of Science:
- Physiology
- Immunology
- Ecology
Background:
- Reactive oxygen species (ROS) are implicated in life-history trade-offs.
- Immune activation can lead to costly ROS upregulation and oxidative damage.
- Prior research focused on post-immune response antioxidant changes.
Purpose of the Study:
- To test if systemic ROS constrain immune activation.
- To investigate the relationship between pre-challenge ROS levels and immune response strength.
Main Methods:
- Measured systemic superoxide (SO) levels before immune challenge.
- Assessed immune response strength using phytohaemagglutinin (PHA) stimulation.
- Studied male and female painted dragon lizards (Ctenophorus pictus).
Main Results:
- Systemic SO levels were negatively related to PHA response strength in males.
- This relationship was not observed in females.
- Suggests systemic SO constrains immune activation in males.
Conclusions:
- Systemic superoxide levels may limit immune activation in male painted dragon lizards.
- Sex-specific selection pressures on immune investment could explain these findings.
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