Interference of an alpha 2 component in immunological determinations of pregnancy-specific beta 1 glycoprotein in serum.

Pregnancy-specific beta 1 glycoprotein (SP1-beta) was purified from human retroplacental blood by sequential anion exchange chromatography, gel chromatography and affinity chromatography. The final preparation appeared to be electrophoretically and immunochemically pure and was in particular free from any component with alpha mobility. The preparation was used as immunogen in rabbits as well as tracer and standard for radioimmunoassay and for cross- and rocket-immunoelectrophoresis.