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== Complement System ==

The '''Complement System''' (pronounced: /ˈkɒmplɪmənt ˈsɪstəm/) is a part of the [[Immune System]] that enhances (complements) the ability of [[Antibodies]] and [[Phagocytic Cells]] to clear [[Microbes]] and damaged cells from an organism, promote [[Inflammation]], and attack the pathogen's cell membrane. 

=== Etymology ===

The term "Complement" was coined in the late 19th century by the [[Nobel Prize]]-winning bacteriologist [[Jules Bordet]]. It refers to the activity of blood serum that completes the action of [[Antibodies]].

=== Components ===

The Complement System consists of a number of small proteins found in the blood, generally synthesized by the [[Liver]], and normally circulating as inactive precursors (pro-proteins). When stimulated by one of several triggers, proteases in the system cleave specific proteins to release [[Cytokines]] and initiate an amplifying cascade of further cleavages.

=== Functions ===

The major functions of the Complement System include:

* Lysis of cells, bacteria, and viruses
* Opsonization, which promotes [[Phagocytosis]]
* Triggering [[Inflammation]] and attracting [[Leukocytes]]
* Clearance of immune complexes and the products of inflammatory injury

=== Related Terms ===

* [[Opsonization]]
* [[Phagocytosis]]
* [[Inflammation]]
* [[Leukocytes]]
* [[Cytokines]]
* [[Antibodies]]
* [[Microbes]]
* [[Immune System]]

[[Category:Medical Dictionary]]
[[Category:Immunology]]
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