A COMPARATIVE-STUDY OF THE PROPERTIES BETWEEN HUMAN FIBRONECTIN ISOLATED FROM PLACENTA OF EARLY AND TERM PREGNANCY

Fibronectin from human early pregnancy (5-8 weeks) placenta (epFN) has been isolated by 2M urea-PBS extraction and purified by heparin-Sepha rose 4B affinity chromatography followed by Sepharose CL-6B gel filtra tion, and compared with that of term placenta (tpFN). According to the analysis on SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Wes tern-blots, epFN was similar to tpFN; both are composed of two 250 KD subunits, larger than 220 KD subunits of plasma fibronectin (pFN). The y reacted with antibodies against pFN and monoclonal antibodies (mAbs) raised against three mainly functional domains of amniotic fluid fibr onectin (amFN), respectively. However, the affinity of epFN with mAb a gainst heparin-binding domain was stronger than that with mAb against gelatin-binding domain; this phenomenon could not be observed with tpF N and pFN. The results of lectin-binding capacity indicated that epFN was not only distinct from pFN but also from tpFN on its carbohydrate composition. We also found there were much more FN-binding proteins in early placenta than in term placenta. The significance of these resul ts are discussed.