Monoclonal Antibodies Against M1 Antigen, A Fucomucin of the Human Gastrointestinal Mucosa

Abstract Mouse myeloma cells SP2 were fused with spleen cells of a mouse immunized with a M1 fucomucin antigen sample carrying A blood group activity isolated from an ovarian mucinous cyst fluid. Out from 100 hybrids, 35 secreted antibodies reacting with Ml using ELISA method. One of them was cloned and 16/26 clones were positive by ELISA. The 10 more positive clones produced actually monoclonal antibodies against A-like blood group substance, the 6 others did not react with ABO red cells but secreted antibodies against M1 antigen. Monoclonal antibodies obtained from one of these last clones stained cells of surface gastrointestinal epithelium by immunofluorescence: gastric columnar cells, duodenal goblet cells, brush border and Golgi apparatus of absorptive duodenal cells, goblet cells of proximal colon (the distal part was always negative). Such monoclonal antibodies showing the absence of fucomucin M1 antigen in the distal colon, could be useful to study mucin modification in precancerous colonic mucosa.