Figure 1.

The inflammatory reflex. The vagus nerve functionally projects into the coeliac plexus which relays signals to the sympathetic splanchnic nerve. Activation promotes release of acetylcholine [ACh] from choline acetyltransferase [ChAT]-expressing T cells which inhibits the release of tumour necrosis factor [TNF] from splenic macrophages. Vagus nerve endings also project into the gut wall and interface with the enteric nervous system through the myenteric plexus, but the role of ChAT⁺ T cells in the gut has not yet been fully elucidated. NE, norepinephrine/noradrenaline. Reprinted from International Immunology 2021;33:349–56].