Adaptive Immunity

Question 1

What is innate immunity

Answer 1

The first line of defence of (non specific) defence whilst adaptive immunity is specific and acquired

Question 2

What does the adaptive immune response consist of

Answer 2

Cell mediated responses and antibody (humoral) responses

Question 3

Describe T cells

Answer 3

T cells drive cell mediated immunity, involves the activation of macrophages,natural killer cells (NK) and antigen specific helper and cytotoxic T lymphocytes

Question 4

Describe B cells

Answer 4

Produce antibodies and drive humoral immunity

Question 5

What is a key feature of the adaptive immune system

Answer 5

Immunological memory, whereby each pathogen is remembered by a signature T cell and/or B cells

Question 6

What are the three main receptors in adaptive immunity

Answer 6

• T cell receptor
• B cell receptor ( immunoglobulins)
• major histocompatibility complex (MHC proteins)

Question 7

Where do T cells mature

Answer 7

The Thymus

Question 8

What peptides do T cells recognise

Answer 8

Recognise peptides presented by APCs through the T cell receptor

Question 9

What is T cell repertoire

Answer 9

Diversity is T cell receptor

Question 10

What is thymus education

Answer 10

Checkpoints in place however ensure T cells only respond to foreign pathogens

Question 11

What are T helped cells

Answer 11

CD4+ function to help supports other immune cells to fight threats

Question 12

What are cytotoxic T cells

Answer 12

CD8+ destroy our own cells which have become infected

Question 13

What are regulatory T cells

Answer 13

Regulate or suppress other cells in the immune system

Question 14

What do all T cells start as

Answer 14

Naive cells and they all have specific receptors

Question 15

What is the CD8 receptor

Answer 15

A co receptor that binds to MHC 1

Question 16

What is a CD4 receptor

Answer 16

A co receptor that binds to MHC II

Question 17

What is CD3 receptor

Answer 17

A co receptor involved in activation of both CD4+ and CD8+ T cells

Question 18

What chains do the majority of T cells express

Answer 18

Alpha and beta chains

Question 19

What chains do the minority of T cells express

Answer 19

Gamma and delta cells

Question 20

What are the three gene segments that encode the variable region of the T cells

Answer 20

• V (variable) (both alpha and beta chains)
• D (diversity) (beta chain only)
• J (joining) (both alpha and beta chains)

Question 21

What are the regions called in the T cells that can change

Answer 21

• constant region
• variable region

Question 22

What are the genes re arranged by in T cells

Answer 22

Somatic recombination

Question 23

What is the process of multiple genes encoding for a T cell receptor called

Answer 23

VDJ recombination

Question 24

What enzyme is used for recombination of genes in T cell receptors

Answer 24

RAG (recombinase) enzymes

Question 25

Where are T cells educated

Answer 25

In the thymus

Question 26

What are the two types of selection

Answer 26

T cells interact with thymic cortical epithelial cells in thymus - positive selection - no recognition = apoptosis - negative selection - recognition of self antigen = apoptosis

Question 27

What is T cell emigration

Answer 27

Positively and negatively selected CD4/CD8+ T cells with rearranged T cell receptors leave the thymus and circulate in blood/lymphatics Some reside in lymph nodes They are still classes as naive

Question 28

What cells prime naive T cells

Answer 28

Mature dendritic cells

Question 29

What three signals are required for the priming of T cells

Answer 29

Signal 1 = activation of T cells Signal 2 = survival and clonal expansion of T cells - signal 1 but no signal 2 is known as anergy Signal 3 = differentiation into subsets of effector T cells (specifically CD4+ helper cells)

Question 30

What is the role of CD4+ T cell subsets (TH1 cells)

Answer 30

Main role is macrophage function Source of interferon - delta

Question 31

What is the main role of CD4+ T cell subsets - Treg cells

Answer 31

Regulatory T cells that function in immune suppression Release inhibitory cytokines Inhibit T cell activation and dendritic cell activation

Question 32

What can happen if there are not enough Treg cells

Answer 32

Extensive inflammation

Question 33

What is the function of CD8+ T cells

Answer 33

Induce host cells to undergo apoptosis

Question 34

What do cytotoxic T cells release

Answer 34

Granzyme/perforin