Monoclonal antibody (mAb) engineering that optimizes binding to receptors present on brain vascular endothelial cells has enabled them to cross through the blood-brain barrier (BBB) and access the brain parenchyma to treat neurological diseases. However, once in the brain the extent to which receptor-mediated reverse transcytosis clears mAb from the brain is unknown. The aim of this study was to determine the contribution of the neonatal Fc-receptor (FcRn) in rat brain efflux employing two diffe...