Fetal- and uterine-specific antigens in human amniotic fluid

Abstract

Removal of the major maternal serum proteins from 2nd trimester amniotic fluid by antibody affinity chromatography revealed various soluble tissue antigens, of which 2 were fetal-specific skin proteins and another, of .alpha.2-mobility, was specific to the uterus and was therefore designated .alpha.-uterine protein (AUP). These proteins were not detected in maternal serum by antibody-antigen crossed electrophoresis. The concentration of AUP in amniotic fluid reached a maximum between 10-20 wk of gestation, suggesting that there is an influx of uterine protein into the amniotic fluid at this stage of pregnancy.