Biomaterial Database

The monocytic receptor for lactoferrin and its involvement in lactoferrin-mediated iron transport. 1994

H S Birgens

Department of Hematology L, Herlev Hospital, University of Copenhagen, Denmark.

Several studies suggest biological functions of the iron-binding neutrophilic glycoprotein lactoferrin that imply an initial interaction with cells from the monocyte/macrophage family. Among these, an important role of lactoferrin as responsible for the inflammatory-induced blood hyposideremia and accumulation of iron in the monocyte/macrophage system has been suggested mainly based on experiments in rodents. In a series of experiments we have examined the binding of human lactoferrin to human monocytes. We have demonstrated the presence of a receptor binding including a high-affinity component and a low-affinity component. The affinity of the binding is compatible with a biological significance of this receptor (KD is about 10(-8) M, and the number of receptors about 10(6) per cell). More than 90% of the lactoferrin will dissociate from the cell. The binding is not truly reversible since lactoferrin will lose its receptor-binding property after dissociation from the cell. The only observed change in the molecule is a small decrease in isoelectric point from 8.9 to 8.8. Lactoferrin is able to translocate at least 50% of its bound iron to intracellular ferritin in monocytes. These findings are compatible with the idea that lactoferrin might be involved in the pathogenesis of the disturbances in iron metabolism observed during inflammation.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007781	Lactoferrin	An iron-binding protein that was originally characterized as a milk protein. It is widely distributed in secretory fluids and is found in the neutrophilic granules of LEUKOCYTES. The N-terminal part of lactoferrin possesses a serine protease which functions to inactivate the TYPE III SECRETION SYSTEM used by bacteria to export virulence proteins for host cell invasion.	Lactotransferrin
D008264	Macrophages	The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)	Bone Marrow-Derived Macrophages,Monocyte-Derived Macrophages,Macrophage,Macrophages, Monocyte-Derived,Bone Marrow Derived Macrophages,Bone Marrow-Derived Macrophage,Macrophage, Bone Marrow-Derived,Macrophage, Monocyte-Derived,Macrophages, Bone Marrow-Derived,Macrophages, Monocyte Derived,Monocyte Derived Macrophages,Monocyte-Derived Macrophage
D008895	Milk, Human	Milk that is produced by HUMAN MAMMARY GLANDS.	Breast Milk,Human Milk,Milk, Breast
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009000	Monocytes	Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.	Monocyte
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D005260	Female		Females