Immunology 1

Question 1

What happens if the immune system under reacts?

Answer 1

Leads to infection, cancer etc

Question 2

What happens if the immune system over reacts?

Answer 2

Leads to allergies, autoimmune diseases (Lupus, IBD, type 1 diabetes)

Question 3

What happens if the immune system goes wrong?

Answer 3

Recurrent Infection 
Cancer 
Allergies 
Autoimmune disease 
Transplant rejections

Question 4

What is immune suppression essential for?

Answer 4

The treatment of autoimmune diseases, allergies, transplantation

Question 5

What is Variolation or inoculation?

Answer 5

Taking a bit of the infection from recovering patients and giving it to a healthy person as protection

Question 6

Describe the physical barriers and their properties?

- SKIN

Answer 6

Skin - waterproof, constantly renewed, had low pH (5.5), low O2 tension (many pathogens need O2)

Question 7

Describe the physical barriers and their properties?

- SUBACEOUS GLANDS (in skin)

Answer 7

Subaceous glands - secrete hydrophobic oils, ammonia (many pathogens dont like) antimicrobial peptides, lysozymes

Question 8

Describe the physical barriers and their properties?

- MUCOUS

Answer 8

Mucous - lines all body cavities, traps invading pathogens

secretory IgA (neutralises bacteria, prevents from attaching to and penetrating epithelial cells)

contains enzymes (lysozymes, defensives, lactoferrin - acts to starve invading bacteria of iron)

Cilia - directly trap pathogens and contribute to the removal of mucous assisted by physical manoeuvres such as sneezing and coughing

Question 9

Describe the physical barriers and their properties?

- COMMENSALE BACTERIA

Answer 9

Symbiotic relationship with host

They compete for nutrients, starve the pathogens

Boost immune response via increased synthesis of vitamins (K, B12)

Production of bactericides which influence other bacteria

reduce pH of the large bowel

Question 10

What happens if external barriers are breached?

Answer 10

The immune system is activated

Question 11

What can eradication of normal flora with broad spectrum antibiotics result in?

Answer 11

Opportunistic infection - organisms rapidly colonise an undefended ecological niche

e.g C.Diff after IV antibiotics, Oral candidiasis after oral antibiotics

Question 12

How does the immune system Identify and eliminate microorganisms and other harmful substances as well as abnormal cancer cells?

Answer 12

By distinguishing ‘self’ molecules from ‘non-self’ molecules

By identifying ‘danger’ signals (e.g. from acute inflammation)

or via combination of the two