16. Immunology part 1

Question 1

What is the immune system?

Answer 1

a network of specialised cells, tissues and soluble factors that co-operate to kill and eliminate cancer cells

Question 2

What does the immune system do?

Answer 2

it can identify and eliminate microorganisms and other harmful substances as well as abnormal cancer cells

Question 3

How does the immune system protect us from harmful substances/ cells?

Answer 3

1. distinguishing self cells from ‘non-self’
2. by identifying ‘danger’ signals e.g. from acute inflammation
3. or via combination of the two

Question 4

How is the immune system modulated for the basic of major advancements in the treatment of disease?

Answer 4

1. vaccinations

2. immunosuppressants/ anti-inflammatory drugs

Question 5

How do vaccines work?

Answer 5

by deliberately introducing of material derived from a pathogen to generate a tricked immune response to develop immunological memory so that in real life, if the pathogen was to invade, it would be recognised quickly

Question 6

What do immunosuppressants do?

Answer 6

1. essential for treatment in auto-immune diseases

2. key for preventing rejection of donor tissue in transplant recipients

Question 7

How do we manipulate the immune system to prevent disease?

Answer 7

1. immunisation
2. anti-inflammatory and immunosurpressant drugs designed to suppress disease
3. cancer immunotherapy

Question 8

What does cancer immunotherapy allow?

Answer 8

enables the immune system to recognise, target and eliminate cancer cells, eking it a potential ‘universal answer’ to cancer

Question 9

Why is there still an emergence of new disease?

Answer 9

• global village (travelling)
• population growth so more crowded environments
• changes in human behaviour (social environments contribute to spread of disease)
• changes in dynamics of other infections
• loss of natural habitat
• interactions with pathogens and humans
• zoonotic transfer e.g. COV-19 from animal to human host

Question 10

What are the 2 types if immunity?

Answer 10

1. innate immunity

2. adaptive immunity

Question 11

What is innate immunity?

Answer 11

• first line of defence
• immediate
• non specific
• no memory

Question 12

What is adaptive immunity?

Answer 12

• secondary
• needs time (days)
• specific
• memory

Question 13

What are features of innate immunity?

Answer 13

• have natural/physical barriers
• soluble factors e.g. cytokines, acute phase proteins, inflammatory mediators, complement proteins
• immune cells; macrophages, mast cells, natural killer cells, neutrophils

Question 14

What are features of adaptive immunity?

Answer 14

• soluble factors e.g. cytokines and antibodies

- immune cells e.g. T cells and B cells

Question 15

What are innate immunity points of pathogen entry?

Answer 15

• digestive system
• respiratory system
• urogenital system
• skin damage

Question 16

What are some routes of attack in innate immunity?

Answer 16

• circulatory system

- lymphatic system

Question 17

What is the major innate immunity barrier? and what does it serve to do?

Answer 17

skin- a protective physical and chemical barrier which has an outer tough surface which is impermeable to micro-organisms

Question 18

How does the respiratory epithelium act as a barrier?

Answer 18

is an inner surface bathed continuously in moving secretions e.g. mucous and acid
- goblet cells secrete mucous which trap pathogens and removes them from the body by cilia

Question 19

What are commensal organisms?

Answer 19

have symbiotic relationship with host and usually at epithelial surfaces where they complete with pathogenic micro-organisms for resources

Question 20

How important are commensal organisms?

Answer 20

• key in eradication of the normal flora with broad spectrum antibiotics commonly results in opportunistic infection
• organisms rapidly colonise an undefences ecological niche
  e. g.
• oral candidiasis after oral antibiotics
• vaginal candidiasis after oral antibiotics
• clostridium difficile infection after intravenous antibiotics

Question 21

When are constitutive barriers less effective?

Answer 21

when breached or attenuated

Question 22

How does our immune system protect us if barriers fail?

Answer 22

by specialised cells e.g.

1. phagocytes (tissue and circulation)
   - orchestrate initiation of response
   - recognise, ingest and kill bacteria and yeasts
2. Degranulating cells (tissue and circulation)
   - orchestrate initiation of response
   - damage and kill multicellular parasites and viruses
3. Secreted proteins
   - complement (induced)
   - chemokines
   - cytokines

Question 23

Give some examples of phagocytic cells

Answer 23

• neutrophils, monocytes and macrophages, dendritic cells

Question 24

Give some examples of degranulating cells

Answer 24

• mast cells, eosinophils and basophils

Question 25

What happens in early innate immune responses?

Answer 25

1. Tissue-resident innate immune cells recognise pathogens as ‘non-self’ and dangerous
   - macrophages and mast cells come together to kill the pathogen and acute, local inflammation by sending out chemokine signals

Question 26

What are features of macrophages?

Answer 26

• phagocytosis
• pro/ anti-inflammatory
• bacterial killing mechanisms
• antigen presentation
• wound healing/ tissue repair

Question 27

What are features of mast cells?

Answer 27

• pro-inflammatory
• parasitic killing mechanisms
• linked to allergy and asthma

Question 28

What do wound sites allow?

Answer 28

for pathogens to evade and establish infection

Question 29

How do these cells recognise pathogens?

Answer 29

pathogens express PAMPS (pathogen associated molecular patterns) which are recognised by specific pattern recognition receptors (PRRs) that are expressed by immune cells

Question 30

How do macrophages located and ingest extracellular bacteria?

Answer 30

by migrating through tissue to hunt down invading pathogens