Preparation of variant-specific anti-human placental phosphatase antisera by immunoabsorption.

Antiserum raised in rabbits sensitized with purified human placental alkaline phosphatase of the rare FD phenotype was absorbed on purified FF phenotype enzyme conjugated to Sepharose. The absorbed antiserum was not able to bind to the F-variant, but was still capable of binding to the D-variant enzyme, determined by electrophoretic retardation and gel filtration. It therefore appears that some allelic variants of placental phosphatase differ in their antigenic structure.