Lecture 3 - Cells & Tissues of the Immune System II

Question 1

What are the four core principles of the immune response?

Answer 1

• Recognition
• Effector
• Regulation
• Memory

Question 2

Which different groups of microbes are present in our body?

Why is this significant?

Answer 2

• Microflora
• Pathogens
The body needs to differentiate between these two groups

Question 3

What does ‘inside the body’ mean?

Answer 3

Translocated an epithelial body

Question 4

What can happen secondary to disturbances to the microflora?

Answer 4

• Allergies

* Increased susceptibility to infections

Question 5

How does the immune system recognise pathogens?

Answer 5

Pattern recognition Receptors; e.g.:
 • Toll like receptors (TLRs)
 • NOD like receptors (NLRs)
 • RIG like receptors (RLRs)
 • C-type lectin-like receptors (CLRs)

Question 6

What do pattern recognition receptors recognise on pathogens?

Answer 6

PAMP: pathogen associated molecular patterns

Question 7

What are the cardinal symptoms of inflammation?

Answer 7

Rubor
Dolor
Calor
Tumour
Function laesa

Question 8

What are the cardinal symptoms due to?

Answer 8

• Enlargement of blood vessels of the site
• Infiltration of cells
• substances that activate nociceptors (Substance P, for example)

Question 9

Why does fever help?

Answer 9

Pathogens have an optimum temperature

By increasing body temperature, we reduce the activity of the pathogen

Question 10

What are the innate effector mechanisms?

Answer 10

• Phagocytosis
• Microbicidals
• Complement cascade

Question 11

How do CTLs kill?

Answer 11

• Once activated, they migrate to the tissue
• Once there, they recognise infected cells that are presenting viral peptide on MHC I
• They release toxic granzymes that kill the infected cell

Question 12

What is immunopathology?

Give an example

Answer 12

When pathology is brought about by the immune response
eg. Viral Hepatitis
• the liver cells are infected
• the immune system starts killing all the liver cells to the point where function is compromised

Question 13

What does the immune system do against toxins?

Answer 13

Antibodies bind and neutralise the toxin, because the toxin can no longer bind and cause damage

Question 14

What are some functions of antibody?

Answer 14

• Toxin neutralisation
• Complement activation
• ADCC
• Opsonisation

Question 15

How is immunopathology generally avoided?

Answer 15

Regulation of the immune response

Question 16

What happens to CD4+ and CD8+ cell populations after a virus is cleared?

How does this happen?

Answer 16

• Massive cell death
• Reduced numbers
• However, there is a population of memory cells that remain

This happens through:
• inhibitory cytokines
• Treg cells

Question 17

What are some inhibitory cytokines?

Answer 17

IL-10

TGF-beta

Question 18

Which Th cells dampen the immune response?

Answer 18

Treg

Question 19

How long can B cells live?

Answer 19

A very long time (e.g. up to 60 years)

Question 20

Why is immune memory important?

Answer 20

When a person is re-exposed, the immune response is primed and will kick in much more quickly

Question 21

Describe the generalised process of inflammation

Answer 21

1. Bacteria present in tissue
2. Macrophages engulf bacteria
3. Macrophages release cytokines & chemokines
4. Increased vascular permeability & vasodilation
5. Recruitment of neutrophils into infected tissue

Question 22

Give a three word description of phagocytosis

Answer 22

Receptor mediated endocytosis

Question 23

Describe the function of Th cells

Answer 23

1. Release of cytokines
2. ‘Help’ for B cells
3. ‘Help’ for macrophages

Question 24

What are CLRs?

List some features

Answer 24

C-type lectin-like receptors
• These are a type of PRR
• Contain a lectin domain
• ‘C-type’ means they require Ca2+ for function

Question 25

What are lectins?

Answer 25

Protein domain that binds carbohydrates