Immunosenescence in wild animals: meta-analysis and outlook

Anne Peters, Kaspar Delhey, Shinichi Nakagawa, Anne Aulsebrook, Simon Verhulst

Research output: Contribution to journalReview ArticleResearchpeer-review

15 Citations (Scopus)

Abstract

Immunosenescence, the decline in immune defense with age, is an important mortality source in elderly humans but little is known of immunosenescence in wild animals. We systematically reviewed and meta-analysed evidence for age-related changes in immunity in captive and free-living populations of wild species (321 effect sizes in 62 studies across 44 species of mammals, birds and reptiles). As in humans, senescence was more evident in adaptive (acquired) than innate immune functions. Declines were evident for cell function (antibody response), the relative abundance of naïve immune cells and an in vivo measure of overall immune responsiveness (local response to phytohaemagglutinin injection). Inflammatory markers increased with age, similar to chronic inflammation associated with human immunosenescence. Comparisons across taxa and captive vs free-living animals were difficult due to lack of overlap in parameters and species measured. Most studies are cross-sectional, which yields biased estimates of age-effects when immune function co-varies with survival. We therefore suggest longitudinal sampling approaches, and highlight techniques from human cohort studies that can be incorporated into ecological research. We also identify avenues to address predictions from evolutionary theory and the contribution of immunosenescence to age-related increases in disease susceptibility and mortality.

Original languageEnglish
Pages (from-to)1709–1722
Number of pages14
JournalEcology Letters
Volume22
Issue number10
DOIs
Publication statusPublished - 1 Jan 2019

Keywords

  • Adaptive immunity
  • ageing
  • eco-immunology
  • gerontology
  • immune senescence
  • inflammaging
  • innate immunity
  • life-history trade-offs
  • PHA
  • senescence
  • wildlife diseases

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