Climate-Driven Immune Gene Expression Profiles in Peromyscus leucopus: Implications for Bacterial Infection Dynamics

Area of Science:

• Ecology
• Immunology
• Climate Change Research

Background:

• *Peromyscus leucopus* mice are key reservoirs for *Borrelia burgdorferi*, the Lyme disease agent.
• Host immune variation is critical for disease dynamics, especially under climate change.
• Understanding host competence is vital for predicting Lyme disease outbreaks.

Purpose of the Study:

• To assess the expression of six immune-related genes in *P. leucopus* across climatic gradients.
• To investigate how climate influences immune gene expression in this Lyme disease reservoir.
• To explore the potential link between climate-driven immune variation and host competence.

Main Methods:

• Ear biopsies were collected from wild *P. leucopus* at eight National Ecological Observatory Network sites.
• Expression of six immune genes (TLR-2, IFN-γ, IL-6, IL-10, GATA3, TGF-β) was analyzed.
• Principal component analysis identified patterns in gene expression related to immune function.

Main Results:

• Two principal components of gene expression were identified, reflecting immune activation/regulation and parasite tolerance/tissue protection.
• Expression of genes associated with immune readiness (PC1) significantly increased in warmer, wetter climates.
• Climate appears to influence immune variation in *P. leucopus*, potentially affecting host competence.

Conclusions:

• Climate variation influences immune gene expression in *P. leucopus* mice.
• Enhanced immune readiness in warmer, wetter climates may relate to host resistance.
• Further research is needed to link gene expression to actual disease transmission dynamics.