Immune System

Question 1

What physical barriers are there?

Answer 1

• skin
• nose hairs
• flow of urine

Question 2

What chemical barriers are there?

Answer 2

• urine pH

- gastric enzymes

Question 3

How would you describe the innate immune system?

Answer 3

• the first line of defence

- non-specific

Question 4

What do complement proteins do?

Answer 4

• promote inflammation
• recruit and activate inflammatory cells
• kill target cells

Question 5

What do Ca proteins do?

Answer 5

They are sent on a mission

Question 6

What do Cb proteins do?

Answer 6

Stay on site

Question 7

How can C3 be activated?

Answer 7

• mannose binding lectin
• classical pathway
• alternative pathway

Question 8

What does C3a do?

Answer 8

Mast cell activation

Question 9

What does C3b do?

Answer 9

Opsonisation

Question 10

What does C5a do?

Answer 10

Mast cell activation and chemotaxis

Question 11

What does C9 do?

Answer 11

Cell lysis (MAC)

Question 12

What do the PRRs detect?

Answer 12

PAMPs or DAMPs

Question 13

What does PRR stand for?

Answer 13

Pattern recognition receptors

Question 14

What does PAMP stand for?

Answer 14

Pathogen Associated Molecular Patterns

Question 15

What effect do the PRRs have?

Answer 15

• Endocytolic - phagocytosis

- signalling (e.g. TLR) - pro-inflammatory mediators

Question 16

How would you describe the acquired immune system?

Answer 16

Specific

Question 17

What two types of cell signalling are present in acquired immunity?

Answer 17

• cytokines

- antigen presenting cells

Question 18

What kind of cytokines are present?

Answer 18

• interleukins (between leukocytes)

- chemokines

Question 19

What are antigens presented by?

Answer 19

MHC I

MHC II

Question 20

What cell does an activated B cell become?

Answer 20

Plasma cell

Question 21

What is IgM?

Answer 21

It is the first antibody

Question 22

Where is IgG found?

Answer 22

Blood antibody

Question 23

Where is IgA found?

Answer 23

Mucosa antibody

Question 24

What is IgE?

Answer 24

Parasite and allergy antibody

Question 25

What is IgD?

Answer 25

BCR (B cell receptor)

Question 26

What steps are involved in neutrophil migration?

Answer 26

1. Margination 2. Adhesion 3. Diapedesis

Question 27

What happens when the virus infects the cell?

Answer 27

It starts replicating and this activates the PRRs (e.g, TLR)

Question 28

What does activation of the PRR do?

Answer 28

- upregulation of IL-8 | - expression of pathogenic peptide on MHC i

Question 29

What do IL-8 and inflammatory mediators do?

Answer 29

Attract dendritic cells and macrophages to the site of infection, where they phagocytose cell debris and viral particles

Question 30

What do the dendritic cells do after phagocytosis?

Answer 30

- They are activated - express viral particles on MHC I and MHC II - Activated APC migrate to the lymph node - DCs activate Th1 (and Th2 to an extent) through signals

Question 31

How does a DC activate Th1?

Answer 31

- antigen presentation via MHC II with TCR (I want you to activate) - stimulation of naïve T cell CD28- co-stimulatory signal (yes I really do want you to activate) - release of IL-12 - differentiation to Th1

Question 32

How are CD8 cytotoxic T cells activated?

Answer 32

- interacts with the DC via MHC I | - Th1 licenses CD8+ ct via IFN-gamma and IL-2

Question 33

What happens to the activated CD8+ ct?

Answer 33

- Memory T cells stay in the lymph node for the next time the pathogen infects the body (faster response) - Effector T cells migrate to the site of infection and look for cells expressing the same peptides on MHC I

Question 34

How do the CD8+ ct trigger apoptosis of infected cells?

Answer 34

They release perforin and granzyme

Question 35

What does perforin do?

Answer 35

Creates holes in the target cell's membrane (perforates the membrane)

Question 36

What does granzyme do?

Answer 36

Triggers a series of reactions leading to the target cell's DNA being chopped up

Question 37

What happens when bacteria infect us?

Answer 37

- complement pathway activated - inflammation - neutrophils and dendritic cells are attracted to the site of infection and carry out phagocytosis