CHARACTERIZATION OF NONMATERNAL SERUM-PROTEINS IN AMNIOTIC-FLUID AT WEEKS 16 TO 18 OF GESTATION

Proteins found in amniotic fluid are mainly serum proteins, probably o f maternal origin. About 5% of the total protein concentration has the potential of being fetal or decidual in origin. Only a few of these p roteins have been isolated and characterised. In order to describe the foetal and decidual components in amniotic fluid more extensively, a polyspecific antiserum to amniotic fluid at weeks 16-18 of gestation w as raised. Specificities in the antiserum to serum proteins were remov ed by adsorption. Several proteins of non-serum protein origin reacted with the antiserum. Three of these proteins were chosen for isolation and further characterisation. With the use of immunological methods, SDS-PAGE and N-terminal sequencing we identified two of the proteins a s C-terminal propeptides of procollagen Type I and Type III, which hav e not hitherto been described in amniotic fluid. The third protein, ca lled here protein-4, showed up as homologous to fetal antigen-1 (FA-1) and human dlk, containing EGF-like domains and associated with growth in neuroendocrine tissues and tumours. (C) 1998 Elsevier Science B.V. All rights reserved.