title: Immunohistochemical demonstration of pregnancy-associated plasma protein A (PAPP-A) in the syncytiotrophoblast of the normal placenta at different gestational ages.
abstract: The immunoperoxidase technique was used to study the localization of pregnancy-associated plasma protein A (PAPP-A) in formaldehyde-fixed paraffin-embedded tissue from normal human placentae at the gestational age of 8, 15 and 40 weeks. Sections of formaldehyde-fixed tissue treated with a proteolytic enzyme and incubated in antiserum against PAPP-A either raised in goats or rabbits showed that PAPP-A was distributed in the cytoplasm of the syncytiotrophoblast. The protein was not found in the cytotrophoblast. Sections without pretreatment with trypsin and incubation in goat anti-PAPP-A showed no staining reaction, whereas incubation in rabbit anti-PAPP-A revealed a staining of the syncytiotrophoblast surface. The results indicate that PAPP-A is probably synthesized in the syncytiotrophoblast.
mesh_terms: D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D006651:Histocytochemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism*
chemical_list: D011257:Pregnancy Proteins; D011266:Pregnancy-Associated Plasma Protein-A