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Updated: Aug 13, 2026

Analyzing the Permeability of the Blood-Brain Barrier by Microbial Traversal through Microvascular Endothelial Cells
Published on: February 14, 2020
The blood-brain barrier protects foreign antigens in the brain from immune attack
1Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pennsylvania 15261.
Abstract:
To examine the role of the blood-brain barrier (BBB) in maintaining immune privilege in the brain, the BBB in the region of stably integrated mouse neural grafts implanted in neonatal rat brains was transiently disrupted by intracarotid infusion of hypertonic mannitol. This led to graft rejection and to prominent expression of major histocompatibility complex (MHC) antigens on cells adjacent to the graft. Grafts in control animals receiving an intracarotid infusion of isotonic saline showed only rare MHC expression and no increased incidence of rejection. Opening the barrier in the absence of a graft caused neither MHC expression nor cellular infiltration within the brain, suggesting that the effects of the hypertonic infusion were not produced by an indirect injury-mediated effect on the host brain. We conclude that the integrity of the blood-brain barrier is an important factor in the relative immune privilege of nonsyngeneic neural grafts.
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