5.3. Innate Immunity II: Humoral Response

Question 1

Acute phase proteins

Answer 1

1. Proteins whose plasma concentration increases in response to inflammation
2. Produced in the liver due to signaling through IL1 and IL6 which are cytokines produced by macrophages and neutrophils

Question 2

Name 5 acute phase proteins

Answer 2

1. C reactive protein (CRP)
2. Mannose binding lectin (MBL)
3. Ferritin
4. Fibrinogen, factor VIII
5. Serum Amyloid A

Question 3

C reactive protein (CRP)

Answer 3

Opsonin on microbes

Activates classical complement pathway

Question 4

Mannose binding lectin (MBL)

Answer 4

Activates mannose binding complement pathway or lectin pathway

Question 5

Ferritin

Answer 5

Binds iron

- inhibits microbe iron uptake

Question 6

Fibrinogen, factor VIII

Answer 6

Cause coagulation

Question 7

Serum amyloid A

Answer 7

Recruitment of immune cells to inflammatory sites

Question 8

Complement proteins

Answer 8

Group of 30 different plasma proteins produced by liver which when cleaved and activated act as defence against microbes in extracellular spaces

Question 9

Complement activation

Answer 9

Proteases which cleave other complement proteins to form active proteases, opsonins or chemoattractants

Question 10

Name 3 pathways of complement activation

Answer 10

1. Classical pathway
2. Lectin pathway
3. Alternate pathway

Question 11

Classical pathway

Answer 11

Activated by CRP or antibodies binding to microbe surface

Question 12

Lectin pathway

Answer 12

Activated by mannose in microbe wall binding to MBL

Question 13

Alternate pathway

Answer 13

C3 converted to C3b in plasma or extracellular fluid

Question 14

Anaphylayoxin

Answer 14

Causes release of histamines by mast cells or chemotaxis of neutrophils and macrophages & larger fragment C3b which binds to microbe surface (opsonin)

Question 15

MASPs

Answer 15

Mannose associated serine proteases

Question 16

Macrophages and neutrophils have receptors for:

Answer 16

C3b

- will phagocytose pathogens coated with C3b

Question 17

Mast cells have receptors for:

Answer 17

C3a and C5a

- release of histamine = inflammation

Question 18

Epithelial cells have receptors for:

Answer 18

C3a and C5a

- increase the permeability of these cells

Question 19

Neutrophils & macrophages have receptors for:

Answer 19

C3a and C5a

- recruit cells to site of damage and infection