APC's.

Question 1

What is the function of APC’s?

Answer 1

To acquire and present exogenous antigens to CD-4+ T helper cells.

Question 2

What are the 3 3 types of professional APC?

Answer 2

Dendtritic cells.

Macrophages.

B cells.

Question 3

Will an infected cell that presents an antigen presents an antigen to the immune system be considered to be an APC?

Answer 3

No.

Question 4

What can all antigen presenting cells present antigens to?

Answer 4

An MHC-2.

Question 5

What is the only APC whose entire role is antigen presentation?

Answer 5

Dendritic cells.

Question 6

What is the best APC?

Answer 6

Dendritic cells.

Question 7

What 3 tissues are dendritic cells not found in?

Answer 7

The brain.

The testes.

Some parts of the eye.

Question 8

What cells are responsible for antigen presentation in the brain, the testes and some parts of the eye?

Answer 8

Macrophages.

Question 9

What is the main role of B cell?

Answer 9

To make antibodies.

Question 10

What receptor is found on a B cell?

Answer 10

A B cell receptor which binds to antigens.

Question 11

What molecule is expressed on the cell surface of APC presenting cells?

Answer 11

MHC-2 molecules.

Question 12

What cells express a very high amount of MHC-2 molecules on their cell surface?

Answer 12

Dendritic cells.

Question 13

What cells express the highest amount of MHC-2 molecules?

Answer 13

Dendritic cells.

Question 14

Can macrophages present any antigen?

Answer 14

No, they must be stimulated before they can present antigens.

Question 15

What is the only cell that macrophages can present antigens to?

Answer 15

Sensitised T helper cells which are T cells that have seen antigens before.

Question 16

What 2 cell types can dendritic cells present antigens to?

Answer 16

Naive T cells.

Sensitised T cells.

Question 17

Can T cells bind to any antigen?

Answer 17

No, the antigen must be bound to an MHC molecule.

Question 18

What kind of antigens are presented by an APC?

Answer 18

Exogenous antigens.

Question 19

What are the 3 things that can bind to an epitope?

Answer 19

A TCR from a CD4 or CD8+ T cell.

A BCR.

An antibody.

Question 20

What is the best antigen presenting cell?

Answer 20

A dendritic cell as they are the only full time antigen presenters.

Question 21

What are the only APC’s that can stimulate a naive T cell?

Answer 21

Dendritic cells.

Question 22

What happens once an antigen has been presented to a naive T cell?

Answer 22

It becomes a sensitised helper T cell.

Question 23

How do immature dendritic cells become mature?

Answer 23

They sample their environment and capture antigens to become mature.

Question 24

Where are mature dendritic cells found?

Answer 24

In the lymph tissue.

Question 25

What do dendritic cells present antigens to?

Answer 25

Naive T cells.

Question 26

Where are dendritic cells found in greatest numbers?

Answer 26

The lymph nodes, skin and mucosa.

Question 27

What is the only antigen presenting cell that can present antigens to naive T cells?

Answer 27

Dendritic cells.

Question 28

Why are dendritic cells essential for activating primary immune responses?

Answer 28

Because they are the only cells that can present antigens to naive T cells.

Question 29

Where are dendritic cells produced?

Answer 29

In the bone marrow.

Question 30

What do dendritic cell use to present antigens to helper T cells?

Answer 30

A MHC-2 molecule.

Question 31

What are the 3 major classes of dendritic cells?

Answer 31

Thymic dendritic cells. Interdigitating dendritic cells. Langerhans dendritic cells.

Question 32

What is the role of thymic dendritic cells?

Answer 32

They educate T cells to recognise self antigens.

Question 33

What happens to T cells that do not recognise self antigens?

Answer 33

They are killed.

Question 34

What are interdigitating dendritic cells?

Answer 34

Mature dendritic cells which interact with T cells in the lymph node.

Question 35

What are Langerhans dendritic cells?

Answer 35

Immature dendritic cells that are found in the skin.

Question 36

Are macrophages good APCs?

Answer 36

They are quite good, mainly because they must be activated before they can present antigens.

Question 37

What cells will macrophages present antigens to?

Answer 37

To specialised T helper cells.

Question 38

Macrophages are the only APC in what 3 tissues?

Answer 38

The brain, the testes and they eye.

Question 39

When will B cells make an antibody?

Answer 39

When they have received antigens.

Question 40

What receptor is found on B cells?

Answer 40

A B cell receptor (BCR) which is a membrane bound antibody.

Question 41

What antigens can a BCR bind to?

Answer 41

Any antigen, not just protein antigens.

Question 42

How do B cells acquire antigens?

Answer 42

By being specific for certain antigens. This means that one B cell will have specificity for a particular antigen.

Question 43

How does a B cell acquire an antigen?

Answer 43

It uses its BCR to bind to an antigen. It then ingests it and processes it. It gives the peptide to an MHC-2 which can present it to a helper T cell.

Question 44

What happens when a B cells BCR binds to an antigen?

Answer 44

The B cell differentiates into an antibody secreting cell known as a plasma cell.

Question 45

What cells help a B cell differentiate into a plasma cell?

Answer 45

Helper T cells.

Question 46

What kind of antibodies are made by B cells?

Answer 46

Antibodies that mimic the antigen that is bound to the BCR.