Anti-Occludin antibodies are directed against the protein encoded by the gene OCLN in humans. The occludin protein has an expected mass of 59.1 kDa, but there are 7 reported isoforms. The protein may also be known as BLCPMG, PPP1R115, PTORCH1, phosphatase 1, regulatory subunit 115, and tight junction protein occludin. Variants of this antigen may also be found in other species, including canine, porcine, monkey, mouse and rat.