Complement Pathway Flashcards
Cleaves c1s to activate protease function
C1r
Binds to antibody that has bound antigen, activates C1r
C1q
Cleaves C2 and C4
C1s
Unknown function
C2a
Activate enzyme of classical pathway
Cleaves C3 and C5
C2b
Mediates inflammation
Anaphylatoxin
C3a
Binds c5 for cleavage of C2b
Binds cell surfaces for opsonization and activation of alternate pathway
C3b
Mediates inflammation
C4a
Binds C2 for cleavage by C1s
Bids cell surfaces for opsonization
C4b
Mediates inflammation, anaphylotoxin, chemotaxin
C5a
Initiates assembly of the membrane attack complex
C5b
Binds c5b
Forms receptor for c7
C6
Binds c5b6, inserts into membrane, forms acceptor for c8
C7
Binds c5b67
Initiates c9 polynerization
C8
Polymerizes around c5b678 to form channel that causes cell lysis
C9m
Alt Path
Mediates inflammation
Anaphylotoxin
C3a
Alt Path
Binds cell surfaces for opsonization and activation of alternate pathway
C3b
Alt Path
Bids membrane bound c3b
Cleaved by factor D
Factor B-B
Alt Path
Unknown
Factor B-Ba
Alt Path
Cleaved form stabilized by P produces c3 convertase
Factor B-Bb
Cleaves factor B when bound to c3b
Alt Path
Factor D
Binds and stabilizes membrane bound c3bBb
Alt Path
Properdin-P
Cleave C2 and C5
Lectin Pathway
MASP
Lectin pathway or
Mannose binding lectin pathway
Activates C1s
C1r