The effect of hydration state and energy balance on innate immunity of a desert reptile

Butler, Michael W.; Moeller, K. T.; DeNardo, D. F.

The effect of hydration state and energy balance on innate immunity of a desert reptile

Abstract

Introduction: Immune function is a vital physiological process that is often suppressed during times of resource scarcity due to investments in other physiological systems. While energy is the typical currency that has been examined in such trade-offs, limitations of other resources may similarly lead to trade-offs that affect immune function. Specifically, water is a critical resource with profound implications for organismal ecology, yet its availability can fluctuate at local, regional, and even global levels. Despite this, the effect of osmotic state on immune function has received little attention.

Results: Using agglutination and lysis assays as measures of an organism's plasma concentration of natural antibodies and capacity for foreign cell destruction, respectively, we tested the independent effects of osmotic state, digestive state, and energy balance on innate immune function in free-ranging and laboratory populations of the Gila monster, Heloderma suspectum. This desert-dwelling lizard experiences dehydration and energy resource fluctuations on a seasonal basis. Dehydration was expected to decrease innate immune function, yet we found that dehydration increased lysis and agglutination abilities in both lab and field studies, a relationship that was not simply an effect of an increased concentration of immune molecules. Laboratory-based differences in digestive state were not associated with lysis or agglutination metrics, although in our field population, a loss of fat stores was correlated with an increase in lysis.

Conclusions: Depending on the life history of an organism, osmotic state may have a greater influence on immune function than energy availability. Thus, consideration of osmotic state as a factor influencing immune function will likely improve our understanding of ecoimmunology and the disease dynamics of a wide range of species.

Title	The effect of hydration state and energy balance on innate immunity of a desert reptile
Creator	Butler, Michael W.
	Moeller, K. T.
	DeNardo, D. F.
Publisher	Frontiers in Zoology
Academic Department	Biology
Division	Natural Sciences
Organization	Lafayette College
Date Issued	2013
Date Available	2013-07-05T13:11:01Z
Type	Article
Language	English
Keyword	Water
	Digestion
	Hemagglutination
	Osmolality
	Hemolysis
	Dehydration
	Energy balance
Bibliographic Citation	Moeller, K. T., M. W. Butler, and D. F. DeNardo. (2013) "The effect of hydration state and energy balance on innate immunity of a desert reptile." Frontiers in Zoology 10: 23.
Standard Identifier	DOI 10.1186/1742-9994-10-23
Standard Identifier	Handle 10385/1259
Permalink	http://hdl.handle.net/10385/1259
Rights Statement	Creative Commons - Attribution
Rights Holders	Butler, Michael W.
	Moeller, K. T.
	DeNardo, D. F.