Initiation
Receptors such as Toll-like receptors (TLR) and nod-like receptors (NLR) will activate the immune system by binding of ligands such as lipopolysaccharides and peptidoglycan. Toll-like receptors are expressed in antigen presenting cells (APCs) such as dendritic cells, B-lymphocytes and macrophages. When the receptors are activated a cascade reaction will take place and substances such as cytokines and antimicrobial peptides will be released.
Read more about this topic: Beta Defensin
Famous quotes containing the word initiation:
“The difficult and risky task of meeting and mastering the new—whether it be the settlement of new lands or the initiation of new ways of life—is not undertaken by the vanguard of society but by its rear. It is the misfits, failures, fugitives, outcasts and their like who are among the first to grapple with the new.”
—Eric Hoffer (1902–1983)
“Until the end of the Middle Ages, and in many cases afterwards too, in order to obtain initiation in a trade of any sort whatever—whether that of courtier, soldier, administrator, merchant or workman—a boy did not amass the knowledge necessary to ply that trade before entering it, but threw himself into it; he then acquired the necessary knowledge.”
—Philippe Ariés (20th century)