CMB1003/L21 Innate Human Response in Action

Question 1

How is cytokine secretion mediated?

Answer 1

Self-limited

Question 2

Describe the action of cytokines. (3)

Answer 2

Pleiotropic
Redundant
Local or systemic
Often influence action or synthesis of other cytokines

Question 3

How do cytokines initiate their actions?

Answer 3

Membrane receptor binding

Question 4

How is the expression of cytokine receptors regulated?

Answer 4

External signals

Question 5

Describe the cellular response to cytokines. (2)

Answer 5

Changes in gene expression
Expression of new functions

Question 6

What are the 3 major functional categories of cytokines?

Answer 6

Mediators and regulators of innate immunity
Mediators and regulators of adaptive immunity
Stimulators of haematopoiesis

Question 7

What are mediators and regulators of innate immunity produced by?

Answer 7

Mainly by macrophages in response to infectious agents

Question 8

What are mediators and regulators of adaptive immunity produced by?

Answer 8

Mainly by T lymphocytes in response to specific recognition of foreign antigens

Question 9

What are stimulators of haematopoiesis regulated by?

Answer 9

Bone marrow stromal cells, leukocytes and other cells
Stimulate growth and differentiation of immature leukocytes

Question 10

Name 3 important cytokines.

Answer 10

IL2
IL1
TNFa
Interferons

Question 11

What are the 2 distinct groups of chemotractive cytokines?

Answer 11

CXC
CC

Question 12

Give another name for CXCL8.

Answer 12

IL-8

Question 13

What is the role of CXCL8? (2)

Answer 13

Chemotactic factor
Recruits neutrophils, basophils and T cells to site of infection

Question 14

What is the role of IL-1B? (4)

Answer 14

Activates vascular endothelium
Activates lymphocytes
Local tissue destruction
Increases access of effector cells

Question 15

What is the role of TNF-a? (3)

Answer 15

Activates vascular endothelium
Increases vascular permeability leading to increased entry of IgG complement
Increased fluid drainage to lymph nodes

Question 16

What is the role of IL-6? (2)

Answer 16

Lymphocyte activation
Increased antibody production

Question 17

What is the role of IL-12? (2)

Answer 17

Activates NK cells
Induces differentiation of CD4 T cells into TH1 cells

Question 18

Describe antimicrobial peptides. (4)

Answer 18

Innate, small peptides
Amphipathic -> destabilise lipid bilayer
Immunomodulatory effects on host cells
Produced by various cells

Question 19

What is the goal of inflammation? (3)

Answer 19

Increased blood supply (vasodilation)
Increased vascular supply (leaky)
Increased expression of adhesion molecules

Question 20

Give 3 triggers of inflammation.

Answer 20

Pathogens
Tissue damage
Disruption/inappropriate immune response

Question 21

Describe the initiation of inflammation. (3)

Answer 21

Bacteria trigger macrophages to release cytokines and chemokines
Vasodilation and increased vascular permeability cause redness, heat and swelling
Inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain

Question 22

Give 3 mediators of inflammation.

Answer 22

Complement products (C5a -> C3a)
Macrophage, T-cell-derived cytokines
Mast cells
Prostaglandins, leukotrienes, thromboxane, NO

Question 23

Describe the local inflammation in response to Gram negative bacteria from cut to hand. (3)

Answer 23

PRR on macrophage stimulated
Release of TNFa but controlled
Positive outcome

Question 24

Describe endotoxic shock. (4)

Answer 24

Excessive cytokine release in Gram-negative bacterial infection
Widespread effects of cytokines on vascular endothelium
Circulatory shock
Disseminated intravascular coagulation (DIC)

Question 25

Describe how systemic inflammation (toxic shock) occurs using the example of Gram negative bacteria in blood. (3)

Answer 25

PRR on macrophage stimulated
Uncontrolled release of TNFa
Negative outcome

Question 26

What is a cytokine storm?

Answer 26

Elevated levels of circulating cytokines and immune cell hyper-activation

Question 27

Give 2 GI host-immune interactions.

Answer 27

Tight junctions
Paneth cells secrete AMPs
Complement
Saliva, pH, bile, peristalsis
Microbiome

Question 28

Describe Crohn’s Disease. (4)

Answer 28

Inflammatory bowel disease
Autoimmune
Autoreactive T cells against intestinal floral agents
Fatigue, fever, abdominal pain, diarrheoa, weight loss, skin lesions

Question 29

Which cells cause inflammation? (2)

Answer 29

Macrophages
TH1 cell infiltration

Question 30

Which humoral components cause inflammation? (4)

Answer 30

Cytokines
Complement
Altered AMP levels
Antibodies