Function
Complement receptor 3 (CR3)(CD11b/CD18) is a human cell surface receptor found on polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages. CR3 is a pattern recognition receptor, capable of recognizing and binding to many molecules found on the surfaces of invading bacteria. CR3 also recognizes iC3b when bound to the surface of foreign cells. Binding to the receptor causes phagocytosis and destruction of the foreign cell.
CR3 belongs to a family of cell surface receptors known as integrins (because they share this particular β chain, they are referred to as β2-integrins), which are extremely widely distributed throughout nature and which generally are important in cellular adhesion and cell-cell interactions in a variety of cells and circumstances.
Upregulation of MAC-1 in the presence of certain factors such as Il-2 may cause a prolongation of the life of the immune cell while the presence of TNF-alpha induces apoptosis and selective removal of the cell.
A fully activated neutrophil may express on its membrane 200,000 or more CR3 molecules.
Absence of CR3 results in reduced binding and ingestion of Mycobacterium tuberculosis in mice. In human mononuclear phagocytes, phagocytosis of Mycobacterium tuberculosis is mediated in part by human monocyte complement receptors including CR3.
Read more about this topic: Macrophage-1 Antigen
Famous quotes containing the word function:
“The more books we read, the clearer it becomes that the true function of a writer is to produce a masterpiece and that no other task is of any consequence.”
—Cyril Connolly (1903–1974)
“Nobody seriously questions the principle that it is the function of mass culture to maintain public morale, and certainly nobody in the mass audience objects to having his morale maintained.”
—Robert Warshow (1917–1955)
“The uses of travel are occasional, and short; but the best fruit it finds, when it finds it, is conversation; and this is a main function of life.”
—Ralph Waldo Emerson (1803–1882)