Description
The neonatal Fc receptor (FcRn), also known as the Brambell receptor, is a protein that in humans is encoded by the FCGRT gene. The neonatal Fc receptor is an Fc receptor which is similar in structure to the MHC class I molecule and also associates with beta-2-microglobulin. It was first discovered in rodents as a unique receptor capable of transporting IgG from mother's milk across the epithelium of newborn rodent's gut into the newborn's bloodstream. Further studies revealed a similar receptor in humans, leading to the naming as a neonatal Fc receptor. In humans, however, it is found in the placenta to help facilitate transport of mother's IgG to the growing fetus and it has also been shown to play a role in monitoring IgG turnover. Neonatal Fc receptor expression is up-regulated by the proinflammatory cytokine,TNF-α, and down-regulated by IFN-γ