[en] A mouse monoclonal antibody (MAb), 47D10, was raised against a human lung adenocarcinoma cell line, A549. 47D10 bound to lines derived from breast, colon, lung, and pancreatic tumors, but not to normal fibroblasts. Granulocytes also expressed 47D10 but red blood cells and lymphocytes were negative. Immunoperoxidase staining of paraffin-embedded tissues indicated that 47D10 was reactive with 36 out of 38 cases of pancreatic adenocarcinoma, but not with chronic pancreatitis, regenerative pancreas or normal pancreas. The 47D10 antigen was a group of surface glycoproteins ranging from 63-97Kd (average Mr 85Kd). The antigen could be labeled by ³⁵S-methionine, ¹²⁵I, tritiated glucosamine, fucose, and mannose. Pulse-chase labeling showed that the 63-97Kd mature antigens were derived from precursors of 63Kd and 65Kd. The mature antigen was sensitive to endoglycosidase F (endo F) whereas the precursors were susceptible to both endoglycosidase H and endo F. Endo F digestion resulted in a polypeptide of 38Kd. Therefore, the 47D10 antigen is composed of at least 55% N-linked carbohydrates. The 47D10 MAb seems to be distinct from previously identified MAb against pancreatic tumors and may be useful in the diagnosis of pancreatic carcinoma