Immunology

Question 1

What is the difference between intracellular and extracellular bacteria?

Answer 1

• Intracellular can enter and survive inside the host organism
• Extracellular cannot survive inside the host once the phagocyte is ingested

Question 2

What is the definition of virulence?

Answer 2

The ability to infect the host and cause disease

Question 3

What are issues with the evolution of HIV?

Answer 3

The antigenic drift is very rapid and therefore outpaces the development of the immune response which causes disease

Question 4

How does the flu spread so rapidly?

Answer 4

The recombination of the RNA sequence which further mutates to cause more epidemics

Question 5

In 1918, what major thing did the Spanish flu do?

Answer 5

Crossed the species barrier

Question 6

What does altering the surface proteins on a pathogen do?

Answer 6

It means they can avoid host immune response

Question 7

What is the difference between a primary and a secondary response?

Answer 7

• Primary response takes 7-10 days and is not very strong
• Secondary response takes 4-6 days and is very powerful, memory improves here due to memory cells

Question 8

What immune response do we depend on in the first few hours/ days?

Answer 8

Innate immunity

Question 9

What can the immune system check to distinguish between self and non-self at a molecular level?

Answer 9

• Bacterial cell wall
• Protein and peptide structures
• Yeast carbohydrates
• Pathogenic DNA
• Viral antigens on host cells

Question 10

What tissue uses only it’s own immune response?

Answer 10

The brain, through the blood brain barrier

Question 11

Why must the immune system give the right amount of response?

Answer 11

Or else it will not clear it or it may damage the host

Question 12

What are the two types of immune response?

Answer 12

Innate and adaptive

Question 13

What are mucus layers?

Answer 13

• On epithelial surfaces
  -Secreted from mucins and glycoproteins
• Slippery so pathogens can’t attach
• Have cilia

Question 14

What are defensins?

Answer 14

• Hydrophobic domains
• 12-50 aa in length
• positive charge
• in all plants and animals
  They kill and inactivate pathogens using an uncertain non-specific mechanism

Question 15

Why are PAMPs useful?

Answer 15

They look for something different in the body which is recognised by PRRs in the blood

Question 16

Name 3 classes of PAMPs

Answer 16

• fMet attracts neutrophils
• peptidogylcans from cell walls
• bacterial flagellae
• lipopolysaccharides (LPS)
• mannans, glucans and chitin from fungi
• motifs from bacterial or viral DNA

Question 17

What do toll receptors do?

Answer 17

Pathogenic fungi bind to repeating motifs which sends signal to nucleus which expresses antifungal defensins.
Basically nucleus feels the signal and inflammatory response is triggered.

Question 18

Where are toll like receptors found?

Answer 18

• epithelial cells
• macrophages
• dendritic cells
• neutrophils

Question 19

How old are TLRs and PAMPs believed to be?

Answer 19

1576 million years old

Question 20

What is evasion?

Answer 20

LPS is replaced with LOS so it is not recognised by immune system and evades it, it mimics a body cell

Question 21

What are the 3 types of phagocyte?

Answer 21

• Macrophage
• Neutrophil
• Eosinophil

Question 22

What two types of cell are granulocytes?

Answer 22

Neutrophils and eosinophils

Question 23

What are neutrophils?

Answer 23

Most common phagocyte which are rapidly recruited but short lived, they have a bright pink nucleus

Question 24

What are macrophages?

Answer 24

They recognise and remove dead and damaged cells, they are long lived

Question 25

What are eosinophils?

Answer 25

They destroy parasites and modulate allergic inflammatory responses, they work together. They also stain with eosin stain.

Question 26

What happens during a respiratory burst?

Answer 26

Increase in oxygen consumption

Question 27

What happens in a killing frenzy?

Answer 27

• Loads of stuff dies
• Stuff inside macrophages die
• Inflammation aids the frenzy
• Can cause septic shock

Question 28

What do interferons do?

Answer 28

• inferfere with vial infection
• activate other mechanisms
• promote apoptosis
• fight cancers

Question 29

How do NK cells work?

Answer 29

Apoptosis is triggered and the bodies left behind are engulfed by phagocytes

Question 30

What does the R number represent?

Answer 30

Number of secondary cases

Question 31

Where do lymphocytes develop and migrate to?

Answer 31

Develop in the bone marrow and migrate to peripheral / secondary lymphoid organs

Question 32

What activates the adaptive immune response?

Answer 32

Dendritic cells activated by binding of pathogens to TLRs

Question 33

Where do T cells develop?

Answer 33

Develop from thymus tissue from thymocytes

Question 34

What do T cells do?

Answer 34

They recognise non self antigens and cause mitosis and clonal expansion of specific T cells. Causes swelling in lymph glands.

Question 35

What do cytotoxic T cells do?

Answer 35

Recognise antigens and activate caspases from signals

Question 36

Where do B cells develop?

Answer 36

Bone marrow

Question 37

What do B cells do?

Answer 37

• Antibody specific secretion
• Recognise antigens as soluble proteins
• Clonal expansion

Question 38

Name the 5 classes of immunoglobulin (Ig)? How are they distinguished?

Answer 38

IgM
IgD
IgG
IgA
IgE
They are distinguishable by their H chains

Question 39

How many polypeptide chains do antigens have?

Answer 39

4

Question 40

What is affinity maturation?

Answer 40

Antibodies made by B cells in lymph nodes improve affinity and become more specific.