Adaptive immunity

Question 1

What is humoral immunity?

Answer 1

Antibody immunity

Question 2

Briefly describe the process of humoral immunity.

Answer 2

Antigen is recognised by receptor on B lymphocyte

B lymphocyte matures to plasma cell and starts producing loads of antibodies against the antigen

Question 3

Which pathogens is humoral immunity better at fighting?

Answer 3

Extracellular bacteria

Secondary viral infections

Question 4

What are the 2 purposes of antibodies?

Answer 4

1. Antigen recognition: Fab regions bind specifically to antigens
2. Antigen elimination: Once antibody has bound to pathogen, its Fc region binds to complement, phagocyte or NK cells which initiates antigen elimination

Question 5

What’s the role of Fab regions of antibodies?

Answer 5

1. Neutralise toxins
2. Immobilise motile microbes
3. Prevent pathogens binding to and infecting host cells
4. Form complexes

Question 6

What’s the role of Fc regions of antibodies?

Answer 6

1. Activate complement

2. Bind to Fc receptors on phagocytes, mast cells, NK cells

Question 7

What do mast cells do?

Answer 7

Release inflammatory mediators

Question 8

Where do T cells mature?

Answer 8

Thymus

Question 9

Name the types of T cells.

Answer 9

T helper
T cytotoxic
T regulatory (TREGs)

Question 10

What do T helper cells do?

Answer 10

Help plasma cells make antibodies

Activate macrophages and NK cells

Help the development of cytotoxic cells

Question 11

What do T cytotoxic cells do?

Answer 11

Recognise and kill infected host cells

Question 12

What do TREGs do?

Answer 12

Suppress immune responses, preventing them getting out of hand

Preventing autoimmunity

Question 13

What does the T cell receptor (TCR) do?

Answer 13

Recognises cell-associated antigens (ones that have been processed already by B cells or dendritic cells

MHC proteins help them do this!

Question 14

What do MHC proteins do?

Answer 14

Take samples from within infected cells and present them on the surface of that cell so that T cells can see that the cell is infected

Question 15

What are cytokines and what do they do?

Answer 15

They are small proteins

Involved in communication between cells of immune response

Produced and act locally

Question 16

What cells make interleukins?

Answer 16

T cells

Question 17

What type of infections are interferons involved in?

Answer 17

Viral

Question 18

What do chemokines do?

Answer 18

Facilitate cell movement / chemotaxis

Question 19

What does CSF stand for? What does it do?

Answer 19

Colony stimulating factor

Involved in leukocyte production

Question 20

What does TNF-a stand for?

Answer 20

Tumour necrosis factor - alpha

Question 21

What cells produce TNF-a?

Answer 21

T cells
Macrophages
NK cells

Question 22

What does TNF-a do?

Answer 22

Activates neutrophils and endothelial cells

Induces cachexia (loss of muscle and body fat)

Question 23

What are the sub-categories of T helper cells?

Answer 23

TH1

TH2

TH17

TREG

Question 24

What do TH1 cells produce?

Answer 24

IL-2
gamma-interferon
TNF-b

Question 25

What do TH1 cells do?

Answer 25

Activate macrophages -> inflammation

Promote cytotoxic T cell production

Induce B cells to make IgG

Question 26

What do TH2 cells produce?

Answer 26

Many interleukins: 4,5,6,10,13

Question 27

What do TH2 cells do?

Answer 27

Activate eosinophils and mast cells

Induce B cells to make IgE which promotes the release of inflammatory mediators: histamine

Question 28

Which T helper cell is involved in allergy and helminth infection?

Answer 28

TH2

Question 29

What do TREGs produce?

Answer 29

IL-10

TNF-b

Question 30

What do TREGs do?

Answer 30

Down-regulate action of all other T cell subsets

Question 31

What agent turns a T helper cell into a TREG?

Answer 31

FOXP3

Question 32

What do Th17 cells do?

Answer 32

Stimulate neutrophils against acute bacterial infections

Also against other cells in autoimmune conditions