Expression of the neonatal Fc receptor (FcRn) at the blood-brain barrier.
The blood-brain barrier (BBB) restricts transport of immunoglobulin G (IgG) in the blood to brain direction. However, IgG undergoes rapid efflux in the brain to blood direction via reverse transcytosis across the BBB after direct intracerebral injection. This BBB IgG transport system has the characteristics of an Fc receptor (FcR), but there is no molecular information on the putative BBB FcR. The present study uses confocal microscopy and an antibody to the rat neonatal FcR (FcRn), and demonstrates the expression of the FcRn at the brain microvasculature and choroid plexus epithelium. Co-localization with the Glut1 glucose transporter indicates the brain microvascular FcRn is expressed in the capillary endothelium. The capillary endothelial FcRn may mediate the 'reverse transcytosis' of IgG in the brain to blood direction.
Schlachetzki
Felix
F
Department of Medicine, UCLA School of Medicine, Los Angeles, California 90024, USA.
Zhu
Chunni
C
Pardridge
William M
WM
D000818:Animals; D001160:Arterioles / Q000166:cytology / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002196:Capillaries / Q000166:cytology / Q000378:metabolism; D002460:Cell Line; D002831:Choroid Plexus / Q000166:cytology / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D051272:Glucose Transporter Type 1; D015395:Histocompatibility Antigens Class I; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism; D008297:Male; D051379:Mice; D008833:Microcirculation; D018613:Microscopy, Confocal; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis; D018482:Muscle, Skeletal / Q000166:cytology / Q000294:innervation / Q000378:metabolism; D009928:Organ Specificity; D051381:Rats; D011961:Receptors, Fc / Q000096:biosynthesis*
D051272:Glucose Transporter Type 1; D015395:Histocompatibility Antigens Class I; D009004:Monosaccharide Transport Proteins; D011961:Receptors, Fc; C495678:Slc2a1 protein, mouse; C495679:Slc2a1 protein, rat; C100688:Fc receptor, neonatal