Lecture 20- Adaptive Immunity 2

Question 1

What do ATC’s do when activated with antigen?

Answer 1

Travel to lymph node

Question 2

Where in lymph node are b and T cells

Answer 2

B cells in lymphoid follicle

T cells in parafollicular cortex

Question 3

Whatcauses autoimmune disease?

Answer 3

When cells act against self antigen

Question 4

Where are b and T cells produced and where do they mature?

Answer 4

Produced in bone marrow

T cells mature in thymus and B cells in tissues

Question 5

Why do lymph nodes swell during infection?

Answer 5

Lymphadenopathy- B cells and T cells become activated

Question 6

What happens with activation of CD4+ T cells also known as T helper cells?

Answer 6

They go on to help B cells produce antibodies

Question 7

Clinically important lymph nodes?

Answer 7

Cervical
Axillary
Inguinal

Question 8

Antibody response?

Answer 8

Bacteria

Question 9

Effector T cell cytotoxic response?

Answer 9

If virus

Question 10

Antigen recognition by T lymphocytes?

Answer 10

Antigen recognition receptor (t cell receptor TCR)

Great diversity to recognise different antigens

CD4+ helper T cells recognise MHC class 2 while CD8+ recognise MHC class 1

Question 11

How are T cells activated on recognition of an antigen?

Answer 11

3 signals

Antigens presented by MHC 1 or 2

Cytokines released

Question 12

Effect of cytokines on activation of CD4+ cells?

Answer 12

Cytokines released depends on type of microbe and cause different sub types of CD4+ cell to arise

can get TH1 cells responsible for cell mediated immunity (intracellular and extracellular pathogens)

TH1 help B cells produce antibodies

Th2 cells responsible for humoral immunity (extracellular pathogens)

TH17 causes neutrophil recruitment and activation

Treg causes immune suppression

Question 13

What happens if there is a virus in an APC?

Answer 13

APC,s have class 1 and 2 MHC molecules so will activate CD4+ and CD8+ cells

Question 14

Effector functions of CD8+ cells?

Answer 14

Require TH1 cells to become activated and have cytotoxic function

Naive CD8+ cells can either become cytotoxic in activation as above or memory CD8 cells

Cytotoxic will kill all MHC class 1 cells

Question 15

B cell antigen recognition?

Answer 15

Do not need antigens to be processed

Endocytosis and present through MHC class 2 to helper T cells

Get antibody and cytokine production

Question 16

Outcome of B lymphocyte activation?

Answer 16

IgM production which is T helper independent

IgG, IgE and IgA which is T helper dependent. This is why IgM is seen first.

Disease can be detected at lower concentration in future

Memory B cells for long lasting immunity

Question 17

What can antigen stimulated B cells become?

Answer 17

Plasma cells which produce IgM and are T cell or thymus independent

Other cell types which are thymus dependent and produce the other antibodies

Memory B cells

Question 18

Relevance of IgM and IgG clinically?

Answer 18

If high IgM and no IgG then first time exposure to antigen.

If IgG present then secondary exposure and immunity should be there

Question 19

Effector functions of antibodies?

Answer 19

IgG- complement activation, can give vertical immunity for 6 months to offspring (autoimmune risk)

IgE- good against parasites

IgA- mucosal immunity

IgM-complement activation