Immunity

Question 1

What is the first barrier of defence for a pathogen to break through?

Answer 1

Epithelia.

Question 2

What can epithelia produce in an immune response?

Answer 2

Cytokines, chemokines and natural antibodies.

Question 3

What is a cytokine?

Answer 3

This is an agent which alters the behaviour of other cells.

Question 4

What is a Chemokine?

Answer 4

These are chemicals which attract other cells.

Question 5

Define opsonisation.

Answer 5

This is a process by which a pathogen becomes coated in a serum which makes it more attractive to phagocytes and therefore is engulfed.

Question 6

What is the role of an inflammatory mediator?

Answer 6

It promotes vascular permeability, and means there is increased migration to the site of infection. This means there are increased macrophages, neutrophils and lymphocytes.

Question 7

What are the signs of infection?

Answer 7

Inflammations which includes heat, swelling, redness and pain.

Question 8

What is the innate immune response?

Answer 8

This is present from birth and not specific to particular pathogens. Is uses cellular and humoral immunity and is involved in triggering and amplifying adaptive immune response.

Question 9

What are the two different immune responses?

Answer 9

Innate and adaptive.

Question 10

Which immune response is enhanced on second exposure?

Answer 10

Adaptive

Question 11

How does adaptive immunity differ from innate immunity?

Answer 11

Adaptive immunity is pathogen specific response.

Question 12

What happens if someone is lacking an innate immune response?

Answer 12

The innate immune system is pretty much essential to life and this is implied by the rarity of inherited conditions. There is considerable impairment to protection when these occur.

Question 13

State two cell types which have phagocytic function.

Answer 13

Macrophages and neutrophils.

Question 14

What is a phagolysosome?

Answer 14

When a pathogen is engulfed it forms a phagosome, then when this fuses with a lysosomes filled with digestive enzymes it leads to a phagolysosome.

Question 15

Describe the structure of a neutrophil.

Answer 15

Neutrophils contain granules. Once activated no more can be synthesised and so when they are all used up, the cell dies.

Question 16

What can be said about a patient with neutrophil deficiency?

Answer 16

They are likely to suffer frequent infections.

Question 17

In what two ways do macrophages help with immune response?

Answer 17

They release necessary cytokines, and they also act as professional antigen presenting cells to the adaptive immunity system.

Question 18

What immune system are natural killer cells part of?

Answer 18

Natural killer cells are part of the innate immune response.

Question 19

What are the two major roles of NK cells?

Answer 19

They kill abnormal cells such as tumours and they pump proteases into cells infected by viruses through pores.

Question 20

What is the complement system in immunity?

Answer 20

Complements are molecules which bind covalently to the surfaces of pathogen marking them for destruction. This is then enhanced by the binding of a pathogen specific antibody.

Question 21

What is the membrane attack complex?

Answer 21

This creates a pore in a membrane so that a complement can bind.

Question 22

What are T and B cells?

Answer 22

These are lymphocytes and are produced from a common lymphoid precursor.

Question 23

What is the role of a T helper cell?

Answer 23

These activate B cells and macrophages.

Question 24

What is a B lymphocyte?

Answer 24

This is also known as a plasma cell. These are antibody producing.

Question 25

Where are T and B cells found?

Answer 25

These are inactive, and travel in the blood. They are activated when an antigen binds.

Question 26

What is meant by the clonal nature of the adaptive immune system?

Answer 26

This means that because each lymphocyte displays a different antigen specific receptor, there must be many different ones, with each one being a progenitor of a clone of daughter cells.

Question 27

What is the problem with clonal distribution?

Answer 27

Lymphocytes of the required specificity are normally too infrequent to mount an effective immune response. Clonal selection rises this frequency of cells of particular antigen specificity

Question 28

How does the immune system recognise differences between host and pathogen?

Answer 28

It looks for differences in amino acid sequence.