Methods: We constructed two types of mutant mice homozygous knockout of Htr2b, the gene encoding 5-HT2B, in IECs (Htr2bΔIEC and Htr2bΔIEC-ER) to study the role of 5-HT2B in AOM/DSS-induced CAC model. This evidence concerns the gene HTR2B and infectious otitis media.