Transferrin receptors on human B and T lymphosblastoid cell lines

Experiments demonstrating the existence of receptors for iron-saturated transferrin on both B and T lymphoblastoid cell lines of human origin are described. Binding of ¹²⁵I-labeled transferrin is rapid, saturable and reversible. It can be specifically inhibited by unlabeled transferrin but not by other proteins. The number of receptors on T cell lines determined by Scatchard analysis is almost double the number on B cell lines but the binding affinities are equal.The putative transferrin receptor can be removed from the cell by the proteolytic enzymes papain and trypsin, and is re-expressed during overnight incubation at 37°C. Resynthesis is inhibited by puromycin. The receptor can be solubilized by deoxycholate, and retains transferrin binding capacity when non-covalently attached to an amphipathic matrix consisting of deoxycholate-coupled poly(L-lysyl) Agarose.