Developmental alterations in the alpha-fetoprotein sugar chain in maternal serum analyzed by lectin affinity electrophoresis.

Our purpose was to investigate developmental alterations of human alpha-fetoprotein (AFP) oligosaccharides in maternal serum by lectin affinity electrophoresis and to compare the AFP glycoforms in maternal serum with those in umbilical cord serum and amniotic fluid. AFP glycoforms were separated by affinity electrophoresis with concanavalin A (Con A), lentil lectin (LCA), erythroagglutinating phytohemagglutinin (E-PHA) and Allomyrina dichotoma lectin (allo A) and detected by sensitive antibody affinity blotting. In maternal serum, increased proportions of Con A-nonreactive AFP (AFP-C1), LCA strongly-reactive AFP (AFP-L3) and E-PHA-reactive AFP (AFP-P4 and AFP-P5) decreased gradually during the early gestational weeks. Allo A-nonreactive AFP (AFP-A1 and asialo-AFP) were found only in amniotic fluids during early gestational weeks. The percentages of these glycoforms at full term were almost the same among those body fluids. Since the glycoforms of maternal serum AFP were close to those of umbilical cord serum AFP, lectin-affinity electrophoretic analysis of maternal serum AFP may be useful for evaluating the developmental state of fetus by examining the nature of AFP sugar chain.