Complement System Flashcards
C3a
- soluble
- stimulates inflammation by acting as a chemoattractant for neutrophils
C3B
fragment becomes covalently attached to the microbial surface and serves as a opsonin to promote phagocytosis of the microbes
C5A
-soluble C5a is a potent chemoattractant that also induces changes in permeability of blode
The AP can be intiated as an _____ when C3B is generated by either CP or LP
amplification loop
The mechanism of MAC formation is identical for the
AP, CP, LP
c1r AND c1s are
serine proteases
The LP is triggered by what
a plasma protien called: manose binding lectin
C1 inhibitor (C1-INH)
inactivates C1R, C1S, MASP1, MASP 2
MCP
Cofactor for factor 1, mediates cleavage for C3b and C4b
DAF
destabilizes c3 and c5 convertase in the CP and AP (decay accelarting activity)
CR1
cofactor for factor 1, mediates cleavage of c3b and c4 b, ALSO DOES DECAY ACC ACTIVITY FOR C3/c5 convertases
C4 binding protein
binds to C4B, decay accelerating and cofactor activity
Factor H
binds to C3b, has decay acc activity of AP c3 and 5 converases and cofactor activity
Factor 1
degrades c3b and c4b with aid of cofactors
cd59
blocks c9 association with c5b -c8 to prevent MAC to form on host cells
s-protein (vitronectin)
binds to c5b -7 and ihibits c9 poly
clusterin
binds to c5b-7 and ihibits gernation of c5b -9
C5a
- anaphylatoxin
- causes contraction of SM
- INCERASES permability of blood vessels
- degranulation of basophils
- chemotaxis and relase of o2 radicals and lysomomal enzymes
c3a
- anaphylatoxin
- causes contraction of SM
- INCERASES permability of blood vessels
- degranulation of basophils
Glomerular dz
- activates immune complexes of the classical pathway of complement
- c5a is a chemoattractant for neutrophils
- c5b -9 forms membrane attack complex (causes protease release)
- production of ROS and inflammatory cytokines by attracted inflammatory cells and production of proteases which will lead to lesions and tissue fibrosis
Hereditary angioedema
- edema in airway, feet, hands, face
- pts have defect in C1 INH gene
- causes continous activation of plasma complement
- C1 INH usually inhibits the porduction of bradykin but now it doesnt thus that increase vasodilation, capillary permability, and fluid edema
Paroxysmal Nocturnal hemogolobin
- PNH cell lacks all proteins linked trough GPI anchor to their cell membranes
- DAF (cd55) and cd59 are complement regulatory proteins (daf ihibits c5 converase and c3 convertase)
DAF (cd55) and CD 559 ARE WHAT
COMPLEMENTARY REGULATORY PROTIENS
CD59 inhibits what
Formation of MAC
How do you treat PNH
Immunotherapy: compstatin and ecluzumab
