Changes in the expression of blood-group carbohydrates during oral mucosal development in human fetuses.

The distribution of the blood-group antigens A, B, H type 2 (A and B precursor), and N-acetyllactosamine (H-type-2 precursor) was studied in human fetal oral mucosa from 30 fetuses. Epithelium was examined from the lip, the alveolar ridge and the hard palate in fetuses representing development from week 10-20 in utero. The blood-group carbohydrate chains were examined in tissue sections by immunofluorescence microscopy. The A- and B-blood group antigens were detected by human blood-group sera, and antigen-H type-2 chains and N-acetyllactosamine were detected by murine monoclonal antibodies. Regional differences in the expression of oral epithelial blood-group carbohydrates occurred during the fetal period. In the labial epithelium that remained unkeratinized, blood-group antigens A and B were present throughout the entire period of fetal development on the cell surface of the spinous and superficial cells, antigen H type 2 was present on parabasal cells, and N-acetyllactosamine was present on basal cells. In the epithelia of the alveolar ridge and the hard palate, the initial uniform staining for blood-group antigens A and B only occurred in the upper cell layers and changed to include a patchy reaction of single cells in the spinous cell layer. The distribution of antigen H type 2 changed simultaneously to include parabasal cells and the entire spinous cell layer.(ABSTRACT TRUNCATED AT 250 WORDS)