Immune state is associated with natural dietary variation in wild mice Mus musculus domesticus

Abstract

The ability, propensity and need to mount an immune response vary both among individuals and within a single individual over time. A wide array of parameters has been found to influence immune state in carefully controlled experiments, but we understand much less about which of these parameters are important in determining immune state in wild populations. Diet can influence immune responses, for example when nutrient availability is limited. We therefore predict that natural dietary variation will play a role in modulating immune state, but this has never been tested. We measured carbon and nitrogen stable isotope ratios in an island population of house mice Mus musculus domesticus as an indication of dietary variation, and the expression of a range of immune‐related genes to represent immune state. After accounting for potential confounding influences such as age, sex and helminth load, we found a significant association between carbon isotope ratio and levels of immune activity in the mesenteric lymph nodes, particularly in relation to the inflammatory response. This association demonstrates the important interplay between diet and an animal's response to immune challenges, and therefore potentially its susceptibility to disease. A plain language summary is available for this article.

Geographical location influences the composition of the gut microbiota in wild house mice (Mus musculus domesticus) at a fine spatial scale

“…Locations are shown as separate colours and shapes to show differences within and between sites. Trapping sites were represented by their respective abbreviations (BL = Burnet’s Leap, LL = Low Light, TTN = Three Tarns Nick, HR = Holyman’s Road, ML = Main Light, HT = High Tarn, FS = Fluke Street, BY = Byres, K = Kettle, PR = Priory, SH = South Horn) and are the same as used in Taylor et al [34]. The OTU composition varies significantly among trapping locations across the island.…”

“…domesticus were caught on the Isle of May, Firth of Forth, Scotland, in October 2015. A total of 11 sampling sites were used as described by Taylor et al 2019 [34]. At each site 15 to 20 traps were laid using 10 separate transect points, each with one or two traps depending on overall size of trapping site.…”

Relationships between immune gene expression and circulating cytokine levels in wild house mice

“…Trapping was conducted across 8 sessions from August 2014 to October 2016, with each session including 4–7 trapping days. Trapping transects were placed in up to 11 locations across the island (Taylor et al., 2019). Longworth traps (Longworth Scientific Instrument Co.) were primarily used, along with small numbers of Ugglan (Granhab) and homemade “Jordan” traps (Perrow & Jowitt, 1995).…”

“…Trapping was conducted across 8 sessions from August 2014 to October 2016, with each session including 4-7 trapping days. Trapping transects were placed in up to 11 locations across the island (Taylor et al, 2019).…”

“…Here, using the extensively studied natural population of M. m. domesticus on the Isle of May (for examples see Berry et al., 1990; Goertz et al., 2019; Taylor et al., 2019; Triggs, 1991), we used qPCR to measure the expression levels of key cytokine genes representing four arms of the adaptive immune response (Th1, Th2, Treg, and Th17), as well as the innate immune response. These were measured from two key immunological tissues; the spleen and mesenteric lymph nodes (MLN).…”