Abstract
In many animals, old age is often associated with a decline in immune function and an increase in chronic inflammation. Neopterin is used as a biomarker of inflammation because it is a byproduct of macrophage activation. In humans and other primates, neopterin typically increases with age and is occasionally also elevated in young individuals, but it has not been studied in bats. Given that bats are particularly long-lived mammals for their size, studying neopterin across the lifespan may reveal whether individuals are resistant to age-related changes in immune activation. We used Enzyme Linked Immunosorbent Assay (ELISA) to estimate neopterin concentration in urine samples collected from wild greater spear-nosed bats (Phyllostomus hastatus) in Trinidad. Greater spear-nosed bats have an extremely polygynous mating system, with male mortality rates nearly double that of females. We estimated age from recaptures, an epigenetic clock, or tooth wear. We used ELISA and gas chromatography-tandem mass spectrometry to estimate urinary cortisol, a glucocorticoid that can influence and respond to inflammation, to assess how cortisol varies with neopterin concentration. Consistent with expectations, neopterin levels were positively associated with cortisol levels in both sexes. Unexpectedly, neopterin levels were negatively related to age in males, but independent of age in females and lower in males during the mating season. These results suggest that this species exhibits sex differences in age-related changes in immune activation that may relate to their female-biased survival.
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Acknowledgements
We thank the Wildlife Section of the Forestry Division of Trinidad and Tobago for their permission and cooperation, S. Ali, S. Mahadeo, R. Radix, L. Rostant, R. Smith, J. Rayner, K. Armenta, and S. Hex for assistance in the field, B. Ross and D. Zava at ZRT Labs, R. Brooke at the Clock Foundation, and J. Rayner, A. Cunningham, K. Armenta, S. Hex, and A. Lawson for comments. This work was supported by the National Science Foundation (DBI-2213824) and the National Institute on Aging (R61-AG078474, R33-AG078474).
Funding
This work was supported by the National Science Foundation (DBI-2213824) and the National Institute on Aging (R61-AG078474, R33-AG078474).
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This research was approved by the University of Maryland Institutional Animal Care and Use Committee (protocols FR-JUL-24-25, FR-JUL-21-46, FR-APR-18-16) under licenses from the Forestry Division of the Ministry of Agriculture, Land and Fisheries, Trinidad and Tobago. All procedures were performed in accordance with guidelines by the American Society of Mammalogists.
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Kaiser, J.A., Adams, D.M. & Wilkinson, G.S. Urinary neopterin exhibits sex and age differences in wild greater spear-nosed bats.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-72992-z
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DOI: https://doi.org/10.1038/s41598-026-72992-z
Keywords
- Inflammation
- Immune
- Immunosenescence
- Aging
- Greater spear-nosed bat
Phyllostomus hastatus
Source: Ecology - nature.com
