Transferrin transports iron through receptor-mediated endocytosis. The iron transport mechanism occurs in the endothelial cells of the blood-brain barrier. Transferrin maintains iron homeostasis
[1] and is an iron-associated marker. Reduced levels of transferrin are observed in severe COVID-19 conditions.
[6] It may bind to other molecules apart from iron, hence it can be used in targeted drug delivery.
[1]