[1][2] The main function of IL-22BP is the regulation of IL-22 biological activity through specific binding which blocks the interaction of IL-22 with its cell surface receptor IL-22R and thus prevents the downstream cellular signalling and response.
IL-22 and IL-22BP interactions play an important role in health and disease and are involved in the regulation of steady-state homeostasis,[1] inflammatory responses[3] and cancer.
IL-22BP shares approximately 34% sequence homology with the extracellular domain of one subunit of the heterodimeric membrane-bound IL-22R, which is the main cellular receptor for IL-22 providing the subsequent signalling.
This homology extends to the secondary and tertiary structure of the proteins allowing specific binding and protein-protein interactions.
Inflammation mediators such as prostaglandin E2 (PGE2),[8] IL-18 and other inflammasome components[4] are known to downregulate IL-22BP production, on the other hand, the presence of retinoic acid, metabolite of vitamin A, is known to induce IL-22BP secretion.
[11][8] Another research study working with il22ra2 knockout mouse model pointed out protective role of IL-22BP in the tumorigenesis of colorectal cancer (CRC) as animals of this genotype had increased tumour formation when compared to wild-type controls.
[3][15] In mice with experimental autoimmune encephalomyelitis (EAE) which is a model of multiple sclerosis (MS) negative effects of IL-22BP on the disease progression were observed, partially due to insufficient repression of pro-inflammatory IFNγ levels by neutralised IL-22.