Effectors of Innate Immunity

Question 1

Explain inflammation

Answer 1

=red, swelling, heat, pain, loss of fxn due to changes in local vasculature and tissue

Question 2

What causes inflammation?

Answer 2

Mast cells and macrophages release mediators that stimulate capillary endothelial cells to dilate causing fluid influx allowing neutrophils to enter and mediate phagocytosis

Question 3

What are the positive and negative effects of inflammation?

Answer 3

+ delivery of oxygen and clotting factors, increase phagocytosis, activates adaptive response
- tissue damage, hypersensitivity, autoimmunity/allergies

Question 4

Explain phagocytosis

Answer 4

A phagocyte (neutrophil, monocyte, macrophage or dendritic cell) fuses with lysosome for contents to be broken down

Question 5

What is the complement system?

Answer 5

A circulating set of about 30 proteins made in the liver. Enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen

Question 6

What are the complement activation pathways?

Answer 6

1. Alternative - 1st to act
2. Lectin - 2nd to act
3. Classical - 3rd to act
   All 3 activate the complement protein, C3 which is cleaved into C3a and C3b

Question 7

What are complement effector functions?

Answer 7

1. Recruit inflammatory cells
2. Opsonization of pathogens for phagocytosis
3. Cytolysis - perforation of cell membranes

Question 8

How does cytolysis occur?

Answer 8

The membrane attack complex (MAC) forms pores on the target cells causing them to burst

Question 9

How is inflammation induced by the complement system?

Answer 9

Anaphylatoxins (fragments produced during complement activation) act on capillary endothelial cells to increase leukocytes and swelling

Question 10

What are effector functions of cell-mediated cytotoxicty?

Answer 10

1. Direct - pathogen destruction

2. Indirect - sick cells die via apoptosis