Behavioural Fever Promotes an Inflammatory Reflex Circuit in Ectotherms

Area of Science:

• Neuroimmunology
• Ectotherm Physiology
• Behavioral Ecology

Background:

• Brain-immune system communication is vital in animals, but its molecular mechanisms under environmental changes are unclear.
• Behavioral fever, a conserved immune response in ectotherms, alters gene expression and inflammation.
• Molecular regulators of the inflammatory reflex during behavioral fever in ectotherms are unknown.

Purpose of the Study:

• To investigate the neural and molecular mechanisms of behavioral fever in fish during viral infection.
• To characterize the neuro-immune crosstalk regulating inflammation in ectotherms.
• To identify molecular regulators of the inflammatory reflex during fever.

Main Methods:

• Fish were exposed to different thermal gradients during viral infection to study behavioral fever.
• Collected blood, spleen, and brain samples to analyze cytokine levels.
• Performed transcriptomic profiling of spleen tissue and measured neurotransmitter activity.

Main Results:

• Identified neural components controlling inflammatory modulation during behavioral fever.
• Observed a neuro-immune crosstalk mechanism for fine-tuning inflammation.
• Found increased cholinergic neurotransmitter activity and anti-inflammatory factors (Il10, Tgfβ) during behavioral fever.

Conclusions:

• Revealed a cholinergic neuronal mechanism for anti-inflammatory responses during induced fever.
• Provided the first molecular characterization of behavioral fever and inflammatory reflex activation in mobile ectotherms.
• Identified key regulators for neuro-immune adaptation to infection in ectotherms.