Source of the pregnancy serum N-acetyl-beta-glucosaminidase isoenzyme during human pregnancy

The antisera to the A and B isoenzymes found in placenta and fetal liver were raised in rabbits. No antigenic difference was found between the fetal liver and adult tissue isoenzymes. Antisera to the placental isoenzymes did not react with the isoenzymes of adult tissues. The antibody raised against the placental B and fetal B liver isoenzyme decreased the N-acetyl-beta-glucosaminidase activity in maternal serum at 38 weeks gestation to the value found in normal human serum. Immunological evidence has been presented that the isoenzyme of N-acetyl-beta-glucosaminidase found only in pregnancy serum was of placental origin.