Innate immunity and testosterone rapidly respond t

Authors: S Davies S Noor E Carpentier P Deviche

Publish Date: 2016/05/17

Volume: 186, Issue: 7, Pages: 907-918

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Abstract

When faced with a stressor vertebrates can rapidly increase the secretion of glucocorticoids which is thought to improve the chances of survival Concurrent changes in other physiological systems such as the reproductive endocrine or innate immune systems have received less attention particularly in wild vertebrates It is often thought that glucocorticoids directly modulate immune performance during a stress response but in many species androgens also rapidly respond to stress However to our knowledge no study has simultaneously examined the interactions between the glucocorticoid androgen and innate immune responses to stress in a wild vertebrate To address this issue we tested the hypothesis that the change in plasma corticosterone CORT in response to the acute stress of capture and restraint is correlated with the concurrent changes in plasma testosterone T and innate immune performance estimated by the capacity of plasma to agglutinate and lyse foreign cells in the Abert’s Towhee Melozone aberti Furthermore to broaden the generality of the findings we compared male and female towhees as well as males from urban and nonurban populations Acute stress increased plasma CORT decreased plasma T in males and decreased innate immune performance but the increase in CORT during stress was not correlated with the corresponding decreases in either plasma T or innate immunity By contrast the plasma T stress response was positively correlated with the innate immune stress response Collectively our results challenge the proposition that the glucocorticoid stress response is correlated with the concurrent changes in plasma T a key reproductive hormone and innate immunity as estimated by agglutination and lysisWe are grateful to Karla Moeller for guidance on scoring lysis and agglutination and to Dale Denardo for use of equipment for the immune assay We thank two anonymous reviewers whose suggestions helped improve this manuscript We thank Grace Gao Marilyn Ramenofsky and John Wingfield for comments on an earlier draft of the manuscriptAll applicable international national and/or institutional guidelines for the care and use of animals were followed All procedures were approved by the Arizona State University Institutional Animal Care and Use Committee and were conducted under current scientific collecting permits Arizona Game and Fish Department US Fish and Wildlife Service and Bird Banding Laboratory The authors declare that they have no competing interests

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