LGALS9 and Allergy: In particular, IEC-derived galectin-9 was identified as a key factor contributing to immune regulation in an in vitro co-culture model combining IEC and immune cells (2, 3, 9, 30) as well as in vivo in a murine food allergy prevention model (5), which was secreted upon exposure to NDO and a bacterial trigger such as TLR9 agonist.