The Complement System

there are more than 30 ____ and _______ proteins in the complement system

soluble; cell-bound

the complement system participates in both…

innate and adaptive immunity

the complement system is produced by…

hepatocytes (liver), monocytes, and epithelial cells of the gastrointestinal and genitouurinary tracts

the complement system works as a…

cascade system

cascade

when one reaction triggers another reaction which trigger others and so on

the functions of complement

• lysis of cells, bacteria, and viruses

• opsonization

• binding to specific complement receptors on cells of the immune system, triggering specfifc cells functions, inflammation, and secretionof immunoregulatory molecules

• immune clearance

opsonization

promotes phagocytosus of particulate Ags

immune clearance

removes immune complexes from the circulation

types of complement activation pathways

• the classical pathway

• the alternative pathway

• the mannan-binding lectin pathway

the classical pathway

• activators: Ag-Ab complexes

• antibodies involved: IgG and IgM

• activation in an orderly fashion of nine major protein components (C1-C9)

• products of activation are enzymes that catalyze the subsequent step

the classical pathway is considered to be…

part of the specific immune response because it relies on antibodies to initiate it