This mAb recognizes a protein of 165-170 kDa，identified as cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is composed of two membrane-spanning domains (MSD)，two nucleotide-binding domains (NBD)，and an R domain. It is structurally similar to multidrug resistance (Mdr1) protein and both are members of the superfamily of ATP-binding cassette (ABC) transporters，also known as traffic ATPases，which are implicated in the movement of various substrates. The CFTR protein is a small conductance adenosine 3'，5'-cyclic monophosphate (cAMP)-activated chloride ion channel found in the apical membranes of epithelia within the pancreas，airway，intestine，bile duct，sweat gland，and male genital ducts. CFTR is a valuable marker of human pancreatic duct cell development and differentiation.
