This monoclonal antibody reacts specifically with Cingulin (a 150 kD polypeptide) present in tight junctions (zonula occludens) of polar epithelia (e.g. colon, duodenum, kidney, liver, pancreas), of transitional epithelia (e.g. bladder epithelium), and of stratified epithelia (e.g. skin, foot sole, tongue, oesophagus, vagina). Negative with endothelia of vessels and capillaries (e.g. in heart and brain). In contrast to Symplekin, using Monoclonal antibody 139.4 Cingulin has been localized exclusively to the tight junction complex. Reactivities on Cultured Cell Lines (tested so far): Carcinoma cell lines (e.g. MCF-7, Caco-2, PLC, A-431), SV80 (fibroblasts), Glioma, MDBK, MDCK, BMGE. Species Reactivity: Tested: Human, Bovine, Mouse and Xenopus laevis. Negative with Rabbit.