Adaptive immunity part 2

Question 1

Where do APC migrate to to present pathogen to T cells?

Answer 1

Parafollicular cortex in lymph tissue

there are lots of T cells here

Question 2

Where do B cells communicate with T helper cells to mature?

Answer 2

Edge of follicle

Question 3

Where do you find most Naive B cells?

Answer 3

Lymphoid follicle (B cell zone)

Question 4

What do CD4 cells become?

Answer 4

T helper cells (recognise MHC class 2)

Question 5

What do CD8 cells become?

Answer 5

Cytotoxic T cells (recognise MHC class 1)

Question 6

Where are B and T lymphocytes produced and mature?

Answer 6

Produced in bone marrow

T cells mature in thymus
B cells mature after contact with antigen

Question 7

Where are B and T cells found?

Answer 7

Blood (70% T of T cells, 5-15% of B cells)

Question 8

Where do T and B cells accumulate?

Answer 8

Lymphoid tissue

mucosa associated lymph MALT, lymph nodes, spleen

Question 9

When does lymphadenopathy occur?

Answer 9

Swelling from activation of B and T cells by antigen

Question 10

Where are common lymph nodes that you can notice enlargement found?

Answer 10

Neck (cervical)
Armpit (axillary)
Groin (inguinal)

Question 11

What receptors do T cells possess to recognise antigen?

Answer 11

T cell receptor (TCR)

Question 12

Parts of TCR

Answer 12

alpha and beta subunit
CD3 complex
either CD4 OR CD8 accessory molecule

Question 13

2 regions of TCR

Answer 13

Variable and constant

Question 14

What allows for diversity of antigen receptors?

Answer 14

Combinatorial diversity (random combinations of the genes to form antigen receptor)

Question 15

What does activation of T lymphocytes require?

Answer 15

Co-stimulation (2 signals are needed)

Question 16

T signals required in activation of T lymphocytes

Answer 16

Signal 1: MHC class 1/2 binding to TCR

Signal 2: B7 protein on APC binding to CD28 on T cell

Signal 3: cytokines

Question 17

What occurs when APC cells are matured?

Answer 17

Express B7 protein that CD28 on T cell can bind to

Question 18

T helper cells involved in cell mediated immunity (intracellular pathogens)

Answer 18

TH1 (T helper cell 1)

Question 19

T helper cells involved with Humoral immunity (against extracellular pathogens eg parasites/worms)

Answer 19

TH2 and TH17

Question 20

Humoral immunity

Answer 20

Defence against extracellular pathogens

Question 21

Cell mediated immunity

Answer 21

Defence against intracellular pathogens

Question 22

Other T helper cell required

Answer 22

T regulator (tolerance and immune suppression)

Question 23

Cells involved in TH2 and TH17 pathway

Answer 23

TH2: B cells (IgE and IgG), Eosinophils, Mast cells
TH17: Neutrophils

Question 24

Cells involved in TH1 pathway

Answer 24

CD8 T cells differentiate
Macrophages
B cells (IgG and IgA)

Question 25

Effector functions of CD8 T cells

Answer 25

Need TH1 and cytokines to activate into cytotoxic T cells

Question 26

What does cytotoxic T cell do?

Answer 26

Kill all infected cells expressing the viral peptides that MHC class 1 present

Question 27

What else can naive CD8 cells become?

Answer 27

Memory CD8 cells

Question 28

How are antigens recognised by B cells?

Answer 28

B cell receptor (BCR)

Question 29

what is BCR?

Answer 29

Membrane bound antibody | Unique specificity for each cell

Question 30

Regions of BCR

Answer 30

Variable region | Constant region

Question 31

How are antigen receptors diverse?

Answer 31

Combinatorial diversity (random combo of genes)

Question 32

What antigens are recognised by B cells?

Answer 32

Macromolecules (lipids, proteins, nucleic acids) | and Small chemicals

Question 33

What do T cell recognise?

Answer 33

Only peptides presented by either MHC class 2 (CD4) or MHC class 1 (CD8)

Question 34

Signals required to activated B cell

Answer 34

Signal 1: BCR engagement Signal 2: TCR engagement Signal 3: Cytokines, CD40 activation

Question 35

BCR engagament signal 1

Answer 35

Antigen processing and presentation | Increased B7 costimulators

Question 36

TCR engagement signal 2

Answer 36

Antigen specific | B7 co-stimulation

Question 37

What occurs after activation of B cell?

Answer 37

Antibody production Affinity maturation in antibody (stronger) Memory B cells

Question 38

IgM

Answer 38

First antibody produced | T helper cell independent

Question 39

IgG, IgA, IgE

Answer 39

T helper cell dependent | Isotope (heavy chain switch) switch from IgM

Question 40

Memory B cell significance

Answer 40

Upon re challenge give faster, stronger and longer antibody response

Question 41

Regions of antibody

Answer 41

``` Top arms: Fab region Bottom leg: Fc region Inner top arms: light chain Outer top arms: heavy chain Ends of top arms: Antigen binding region Area connecting arms and leg: Hinge region ```

Question 42

What does heavy chain determine?

Answer 42

Isotope of antibody (IgG/IgM)

Question 43

What do antbody isotopes switch between?

Answer 43

Originally IgM | Then IgG, IgA or IgE (thymus dependent)

Question 44

What happens to antibody response if body is exposed to antigen for a second time?

Answer 44

``` Faster Stronger Longer duration Higher affinity Isotope switch (IgM to IgG) ```

Question 45

IgG functions

Answer 45

Fc dependent phagocytosis Complement activation Neonatal immunity Toxin/virus neutralisation

Question 46

IgE functions

Answer 46

Immunity against helminths | Mast cell degranulation (allergies)

Question 47

IgA function

Answer 47

Mucosal immunity

Question 48

IgM function

Answer 48

Complement activation

Question 49

Medical achievements from adaptive immune response

Answer 49

``` Disease prevention (vaccination) Immunoglobulin therapies (for immune deficiency) Immediate protection (transfer antibodies) Diagnostic tests (Infectious diseases, autoimmune, HLA and blood types) ```