Initiation
It is triggered by antigen-bound antibody molecules. (The only antibodies capable of binding are two units of IgG or one IgM, although IgM is more effective at activating complement. IgG4 cannot bind, but the other three IgG types can.) It is the binding of Fc region to the C1 component that initiates this pathway. The classical pathway can also be triggered by binding of C1 to some types of structures on the target microbe. Also, it can be triggered by C-Reactive Protein binding to microbic polysaccharides such as phosphocoline.
Read more about this topic: Classical Complement Pathway
Famous quotes containing the word initiation:
“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)
“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)