Skip to main content
Dryad

Prior exposure to long day photoperiods alters immune responses and increases susceptibility to parasitic infection in stickleback

Whiting, James1; Mahmud, Muayad2; Bradley, Janette3; MacColl, Andrew3

Published Nov 06, 2020 on Dryad. https://doi.org/10.5061/dryad.dz08kprv7

Data files

Nov 06, 2020 version files 104.18 KB

Abstract

Seasonal disease and parasitic infection are common across organisms, including humans, and there is increasing evidence for intrinsic seasonal variation in immune systems. Changes are orchestrated through organisms’ physiological clocks using cues such as day length. Ample research in diverse taxa has demonstrated multiple immune responses are modulated by photoperiod, but to date, there have been few experimental demonstrations that photoperiod cues alter susceptibility to infection. We investigated the interactions among photoperiod history, immunity, and susceptibility in laboratory-bred three-spined stickleback, a long-day breeding fish, and its external, directly-reproducing, monogenean parasite Gyrodactylus gasterostei. We demonstrate that previous exposure to long day photoperiods (PLD) increases susceptibility to infection relative to previous exposure to short days (PSD), and modifies the response to infection for the mucin gene muc2 and Treg cytokine foxp3a in skin tissues in an intermediate 12L:12D photoperiod experimental trial. Expression of skin muc2 is reduced in PLD fish, and negatively associated with parasite abundance. We also observe inflammatory gene expression variation associated with natural inter-population variation in resistance, but find that photoperiod modulation of susceptibility is consistent across host populations. Thus, photoperiod-modulation of the response to infection is important for host susceptibility, highlighting new mechanisms affecting seasonality of host-parasite interactions.