Monoclonal antibody 7H6 reacts with a novel tight junction-associated protein distinct from ZO-1, cingulin and ZO-2

A monoclonal antibody, 7H6, was generated using a bile canaliculus-rich membrane fraction from rat liver as the antigenic substrate. 7H6 produced immunofluorescence patterns at the junctional complex regions of the hepatocytes and in rat intestine, patterns similar to those generated by antibodies to the junctional proteins ZO-1 and cingulin. However, immunoblot analysis showed that the antigen recognized by 7H6 was distinct from these proteins. The nature and function of this antigenic protein is yet to be elucidated.