OUP-16 is a potent and selective histamine H4 receptor agonist. OUP-16 is a full hH4R agonist with 40-fold selectivity over the hH3R and superior to its (2S,5S)-configured optical antipode. The H4R is expressed in various cells of the immune system, suggesting a role in inflammatory, autoimmune, and_x000D_
allergic disorders.