X Complement A group of serum proteins that

X Complement A group of serum proteins that activates each other in an orderly fashion to generate biologically active molecules. Like enzymes, opsonins (Candy Coat) Anaphalatoxins (Histamine like) and Chemotaxins (Draw cells to the site)

http: //users. rcn. com/jkimball. ma. ultranet/Biology. Pages/C/Co mplement. html

DISCOVERY In 1894, Pfeiffer discovered that Vibrio cholerae were lysed in vitro by the addition of guinea pig anti-cholera serum.

Heating the serum to 56 C for 30 min abolished this activity

, but did not abolish the biological activity of antibodies as passive resistance could be transferred.

He also discovered that the lytic activity could be re-established with the addition of fresh serum to the heat treated serum.

From this he concluded that an additional component (in addition to Ab) was present in the serum. He called this substance complement.

JULES BURDET WAS AWARDED THE NOBEL PRIZE IN MEDICINE IN 1919 FOR HIS DEMONSTRATION OF THE ACTIVITY OF COMPLEMENT

A. Pathways 1. Classical – Complement binds with Ag-Ab complexes – especially Ig. M’s; Ig. G’s fix complement to a lesser extent. This is the usual way complement is activated. 2. Alternate - cell walls of some (very few) bacteria and yeast in combination with several serum factors

B. BIOLOGICAL ACTIVITY 1. lyse membranes 2. degranulate mast cells anaphylatoxins 3. chemotaxins- attract phagocytic cells (move from low conc. to high conc. )

4. immune adherence - Ag w/ Ab and complement bind to blood vessels 5. opsonization - coating antigen to render the cell more attractive to phagocytic cells