IL22

Interleukin-22 (IL-22) is a cytokine in the interleukin-10 family that plays a prominent role in mucosal immunity and tissue repair. It is produced by a range of immune cells, including Th17 and Th22 cells, gamma delta T cells, innate lymphoid cells (particularly ILC3), and natural killer cells. Unlike many cytokines, IL-22 mainly acts on non-hematopoietic tissues such as epithelial cells in the gut, skin, and liver.

The biological effects of IL-22 are mediated through a heterodimeric receptor composed of IL-22R1, which is expressed mainly on epithelial and other non-hematopoietic cells, and the shared subunit IL-10R2. Upon receptor engagement, signaling primarily activates the JAK1/TYK2-STAT3 pathway. The activity of IL-22 is modulated by a soluble antagonist, IL-22 binding protein (IL-22BP), which can sequester IL-22 and prevent receptor binding.

IL-22 exerts several protective and restorative functions. It enhances barrier integrity by inducing antimicrobial peptides, mucins, and other molecules that support epithelial defense and repair. It also promotes epithelial cell proliferation and survival, contributing to regeneration after mucosal injury in the intestine and liver. IL-22 can work synergistically with other cytokines such as IL-17 to amplify inflammatory responses, which can be beneficial for host defense but may contribute to pathology in chronic inflammatory diseases.

Clinically, IL-22 signaling is a target of interest for therapies aiming to promote mucosal healing or to dampen pathogenic inflammation, depending on disease context. Research continues to define the conditions under which IL-22 signaling is protective versus pathogenic and to develop strategies that modulate this axis accordingly.