Block 1 Lecture 6 -- Phagocytosis and Complement Flashcards
What cells phagocytose?
1) neutrophils
2) mast cells
3) DCs
4) monocytes
5) macrophages
How is phagocytosis mediated?
by PRRs upon PAMP recognition (mannose receptor, scavenger receptor)
What are the functions of complement?
1) opsonize
2) promote phagocyte recruitment
3) directly kill
How is the alternative complement pathway activated?
directly by PAMP/microbe after C3 is spontaneously cleaved
How is the lectin pathway activated?
MBL binds mannose
ficolin binds NAG or lipoteichoic acid
How is the classical pathway activated?
C1 binds Ab (usually IgM)
What is the function of C3a and C5a?
inflammation
What forms the membrane attack complex?
poly-c9 pentamer binding
Which 2 complement pathways are most similar?
lectin + classical
How does snake venom affect complement?
induces C3 cleavage for uncontrolled inflammation
– organ failure
How might complement be over-activated?
lack of inhibitor proteins
– C1-I deficiency leads to hereditary angioedema; must use C1 esterase inhibitor
How might complement be under-activated
lack of activator proteins
