Cold Exposure & γδ T Cells
Are you a regular cold swimmer or do you take cold showers to boost your health? Curious about how your immune system reacts to cold exposure? Our recent study provides insights into the body's systemic immune response during cold acclimation. In cooperation with the Muscle physiology group, we used a rat model to gain detailed insights. We also included a group of regular cold swimmers to ensure our findings had human relevance. Our study explored the complex interplay between immune cells, neural signaling, and thermoregulation.
A single day of cold exposure triggered a significant stress response, which led to the production of proteins in white adipose tissue (WAT). This, in turn, activated brown adipose tissue (BAT), a special type of fat that facilitates "nonshivering thermogenesis," which maintains core body temperature and promotes weight loss due to its high metabolic activity.
After two weeks of acclimation, we observed a significant shift in the immune system, with changes in cytokine production in both WAT and BAT. Prior research has indicated the role of γδ T cells in thermoregulation. This unique subset of T cells is abundant in barrier tissues like the skin, gut, and adipose tissue. They act as a first line of defense and play critical roles in immune surveillance and tissue homeostasis.
Our study confirmed the systemic importance of γδ T cells during cold exposure, particularly in sensing environmental stressors. We found that cold acclimation significantly alters gene expression in γδ T cells, driven primarily by neural signals. This further emphasizes the role of the neuro-immune axis in the process of cold acclimation. It is noteworthy that in the face of a pathogenic challenge, the weight of BAT in cold-exposed rats remained stable, underscoring the body's priority in maintaining core temperature. However, their immune response to TLR2 stimulation was indeed altered.
These findings highlight the dynamic regulation of immune processes during cold acclimation, with γδ T cells playing a crucial role in bridging the immune system's response to environmental changes and ensuring effective thermoregulation.