Figure 2.

Maternal IgG in the syncytiotrophoblast (STB) from early-gestation placentas co-localizes with CMV glycoprotein B (gB) in vesicles without viral replication. Placental biopsy specimens shown are from immune donors with high neutralizing antibody titers. Tissue sections were co-stained for human IgG and gB (a), placental lactogen (PL) and CMV gB (b), FcRn and cytokeratin (CK) (c), and transferrin receptor (TR) and CK (d). Insets show the staining pattern in the syncytiotrophoblast surface that contacts maternal blood. Nuclei counterstained with TO-PRO-3 iodide. CTB, cytotrophoblasts; VC, villus core.