The antibody MEM-75 reacts with an extracellular epitope of CD71 antigen (transferrin receptor), a 95 kDa type II homodimeric transmembrane glycoprotein expressed on activated B and T lymphocytes, macrophages and erythroid precursors, it is lost on resting blood leukocytes. The antibody MEM-75 does not block binding of transferrin to the receptor.
Transferrin receptor,CD71 (transferrin receptor) is a type II transmembrane glycoprotein expressed as homodimer in erythroid blood cell line and in activated leukocytes. Upon binding of holotransferrin (complex of transferrin and iron ions), CD71 is internalized by clathrin-mediated endocytosis. Acidification of endosomes by vesicular membrane proton pumps leads to dissociation of iron ions, whereas transferrin (apotransferrin) remains associated with CD71 and recycles to the cell surface, where it is released upon exposure to normal pH . CD71 is also involved in uptake of non-transferrin bound iron.,TfR1, TfR, TR, Trfr, T9, p90, TFRC