Plasma Cascades

Question 1

Hageman factor (factor XII) initiates a cascade to produce what?

Answer 1

1) Bradykinin
2) Complement (C3a, C5a)
3) Clotting factors (thrombin, plasmin, fibrin)

Question 2

Sensor for Classical, Lectin, Alternative Pathways

Answer 2

Classical: C1q

Lectin: MB-Lectin or Ficolin

Alternative: C3(H2O)

Question 3

C3 convertase for Classical, Lectin, Alternative Pathways

Answer 3

Classical: C4b2a

Lectin: C4b2a

Alternative: C3(H₂O)Bb or C3bBb

Question 4

C5a (anaphylotoxin)

Answer 4

Chemotaxis for leukocytes

Edema (Increase vascular permeability)

Release histamine from mast cells

Question 5

C3a (anaphylotoxin)

Answer 5

Edema (Increased vascular permeability)

Release histamine from mast cells

Question 6

What are the three results of complement?

Answer 6

1) Recruit inflammatory cells (using C5a, and indireclty…C3a)
2) Opsonize (using C3b on surface)
3) Membrane attack complex

Note: complement good for encapsulated bacteria (ie Neisseria)

Question 7

Protease Inhibitor

Answer 7

Inhibits effects of inflammatory proteases outside areas of inflammation

Alpha1 protease inhibitor (Alpha1-antitrypsin): inhibits elastase in the lung (smoking inhibits Alpha1-antitrypsin so you get too much breakdown of elastin = emphysema)

C1 inhibitor: inhibits plasma kallikrein and C1s (deficiency causes inflammation = hereditary angioedema)

However, alpha2-macroglobulin deficiency doesn’t cause anything bad to happen

Question 8

DAF

Answer 8

Displaces Bb from C3b (alternative pathway)

Displaces C2a from C4b (classical and lectin pathways)

Question 9

CD59 (protectin)

Answer 9

Prevents formation of membrane attack complex

Question 10

C-reactive protein

Answer 10

Measured in clinic, if high means inflammation

Initiates binding of complement

(Specifically binds C-polysaccharide of S. pneumoniae)