Characterization of two pregnancy associated serum proteins with pregnancy specific beta 1-glycoprotein (PS-beta-G)-determinants.

The existence of two pregnancy associated, partially identical glycoproteins with PS-beta-G determinants were demonstrated in serum from pregnant women. Crossed and crossed-line immunoelectrophoretic analysis of pregnancy sera revealed two precipitates with alpha- and beta-mobility, respectively. The ratio between the precipitation areas in various samples could be related to three different types of precipitation patterns observed in rocket immunoelectrophoresis. This variation in precipitation pattern could so far not be related to the progression of any obstetric parameters. The diphasic shape of the precipitate in crossed immunoelectrophoresis was not changed by incubation with normal human male serum or antibody to normal human serum. Incorporation of 4% PEG in the gels enhanced the precipitate in the alpha-region. The cross-reactive glycoproteins were detected in all pregnant women examined. These results point to the need for specific antibody preparations permitting separate quantitation of the two antigen populations with PS-beta-G determinants.