Uptake and intracellular routing of peroxidase-conjugated immunoglobulin-G by the perfused human placenta.
Selected lobules of term human placenta were extracorporeally perfused and human immunoglobulin-G complexed to horseradish peroxidase (IgG-HRP) was added to the maternal perfusate. After different durations of perfusion IgG-HRP was visualised by use of diamino-benzidine cytochemistry. Within the first 10 min of perfusion IgG-HRP was found bound to microvilli and coated pits of the syncytiotrophoblast; internalisation into coated vesicles and tubulo-vesicular bodies was also observed. Subsequently, IgG-HRP was found in multivesicular bodies and by 30 min appeared in basal vesicles, the frequency of the latter event increasing with time. No routing of IgG-HRP into Golgi regions or lysosomes could be detected. by 60 min IgG-HRP was found in a few caveolae of fetal endothelium of both terminal and intermediate villi. IgG-HRP was not found in intercellular clefts of the endothelium. The pattern of uptake and routing observed suggests a receptor-mediated transcytosis of IgG-HRP across the syncytiotrophoblast and a transcellular pathway through the endothelium.
Department of Obstetrics and Gynaecology, Charing Cross and Westminster Medical School, West London Hospital, United Kingdom.
L
L
Leach
B M
BM
Eaton
J A
JA
Firth
S F
SF
Contractor
D000818:Animals; D002417:Cattle; D004705:Endocytosis; D004727:Endothelium / Q000032:analysis; D005260:Female; D005333:Fetus / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000493:pharmacokinetics*; D008854:Microscopy, Electron; D010477:Perfusion; D010920:Placenta / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism
D007074:Immunoglobulin G; D006735:Horseradish Peroxidase