Human fetal bone alkaline phosphatase: preliminary immunologic studies

A partially purified human fetal bone alkaline phosphatase preparation (B-APf) exhibits a class of antigenic determinants not found on any adult bone or liver isoenzymes as well as a set of determinants which it shares with adult bone and liver. The evidence for this is the quantitative immunotitration data which demonstrate the expected precipitation of L-AP, B-APa, B-APf and K-AP by the anti-B-APf reagent at equivalence. However, at high antibody excess, I-AP and P-AP are also precipitated. Conversely, by employing an immunosorbent column of Sepharose-purified L-AP, one can remove the component carrying the antigenic determinants shared with L-AP, B-APa and K-AP. Remaining in solution are antibodies which recognize determinant(s) shared by B-APf, P-AP and I-AP.