IL13 and infection: The neuropeptide CGRP, which is expressed by both the ENS and extrinsic sensory neurons, also antagonizes ILC2 expansion and IL-13 expression in intestinal type 2 immunity (Fig. 3c).80 Recent work shows that ILC2s also express CGRP during infection, mediating auto-inhibition of IL-13 production, suggesting a negative feedback loop for ILC2 regulation.80