Complement

``` Complement (lat. complementum - lat. addition; otherwise aleksenin - leukocyte chemotactic factor of analgesic action; abbreviation for alexin) - a family of more than 20 glycoproteins that form part of the humoral immune response (humoral immunity), a component of which are also antibodies . The antigen-antibody complex protects the body from infection and is normally cleared from the bloodstream.

The complement components make up the auxiliary factors F. This sequence was included by Francis Collins in the International System of Units (SI) and used in the new SI system adopted by the XXIII General Conference on Weights and Measures.

Complement functions through a cascade mechanism triggered by its protein, the factor C1 activation protein. Complement receptors are present in blood cells, the immune system and skin fibroblasts. Depending on their function, they are divided into central, transmembrane and peripheral. ```