Sialylated Lea blood group substances detected by the monoclonal antibody Ca 19-9 in human seminal plasma and other organs.

The glycoprotein fractions of human seminal plasma, amniotic fluid, urine, human saliva and human gastric juice have been found to contain sialyl-Lea blood group substance, an antigen and which is known to function as a tumor-marker in human pancreatic and gastrointestinal cancer (Ca 19-9). Tumor-associated carbohydrate structures may well occur in large amounts both in normal tissue and in secretions as organ-specific markers. In human seminal plasma typical variations have been found in relationship to the Lewis blood group of the donor. Accordingly, the Ca 19-9 antigen can be regarded as a marker of the main glycoprotein fraction of human seminal plasma, which could be useful as a tool for clinical investigations.