IMMUNOHISTOCHEMICAL AND GLYCOHISTOCHEMICAL LOCALIZATION OF THE BETA-GALACTOSIDE-BINDING S-TYPE LECTIN IN HUMAN PLACENTA

The localization of the beta-galactoside binding lectin was studied im munohistochemically on acetone-fixed cryostat sections of full-term pl acental tissue using a biotinylated monoclonal antibody and glycohisto chemically applying biotinylated asialofetuin and lactosylated bovine serum albumin. On blots of placental tissue lysates the lectin is reco gnized by the biotinylated lactosylated bovine serum albumin. The glyc oconjugate recognition of the lectin on blots was inhibited in the pre sence of 0.1 M lactose showing the specificity of the interactions. Th e anti-lectin monoclonal antibody stained syncytiotrophoblast and trop hoblastic cells. Both reagents applied for glycohistochemistry stained syncytiotrophoblast and trophoblastic cells of placental villi and th e trophoblastic layer of extraplacental membranes. A strong uniform cy toplasmic staining was characteristic for syncytiotrophoblast and to a lower extent for cytotrophoblastic cells. The localization of the lec tin is discussed with respect to a possible immunosuppressive function .