Localization of p43 placental isoferritin in human maternal-fetal tissue interface.
OBJECTIVE
Human placental isoferritin, which is composed of a 43-kd protein subunit, is exclusively reactive with the CM-H9 monoclonal antibody. The p43 exerts immunosuppressive activity during pregnancy. The aim of this study was to localize the expression of p43 in the maternal-fetal tissue interface during normal gestation.


METHODS
Villous tissues samples were collected between 5 and 20 weeks' gestation and at term from uncomplicated pregnancies. Immunohistochemical localization of p43 was performed with CM-H9 monoclonal antibody.


RESULTS
During the first trimester p43 was highly expressed in syncytiotrophoblast, Hofbauer cells, and decidual macrophages. From 15 weeks' gestation onward expression in the syncytiotrophoblast was below the level of detection; however, p43 was demonstrated in villous Hofbauer cells and decidual macrophages throughout gestation.


CONCLUSIONS
Expression of p43 was demonstrated on both sides of the maternal-fetal tissue interface, with localization dependent on gestational age. This may suggest its immunologic function throughout pregnancy. First-trimester syncytiotrophoblast displayed high p43 levels, which disappeared later on, whereas maternal serum p43 level continued to increase, which suggests an extraplacental source for p43.
Maymon
R
R
Molecular Immunology Unit, Felsenstein Medical Research Center, Rabin Medical Center, Tel Aviv University, Tel Aviv, Israel.
Jauniaux
E
E
Greenwold
N
N
Moroz
C
C
D002824:Chorionic Villi / Q000378:metabolism; D005260:Female; D005293:Ferritins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second
D005293:Ferritins