10.4 The Adaptive Immune System: Humoral & Cell-Mediated Immunity

Question 1

Can CD4 and CD8 T cells recognise antigens if these antigens are in their natural form?

Answer 1

“Nuh Uh”

They can only recognise antigens that are processed and presented to them through their T-Cell receptor

Question 2

What is the role of Major Histocompatibility complex?

Answer 2

• Binds to processed antigens
• Enables T cells to recognise antigens at their TCRs

Question 3

Draw a diagram of antigen processing and presentation of a peptide

Answer 3

10.4.docx

Question 4

Which MHC class presents to which type of T cell?

Answer 4

Class 1: CD8
Class 2: CD4

Question 5

Which MHC class corresponds to endogenous and exogenous peptides?

Answer 5

Class 1: Endogenous
Class 2: Exogenous

Question 6

Describe an MHC class 1 molecule. What type of cell is it presented on?

Answer 6

• Yellow Alpha Protein (1,2 and 3)
• Blue Beta 2 microglobulin (not covalently associated)
• Expressed on nucleated cells

Question 7

Describe an MHC class 2 molecule. What type of cell is it presented on?

Answer 7

• Dark Alpha Protein (1 and 2)
• Light Beta protein (1 and 2)
• Expressed on antigen presenting cells

Question 8

Draw a diagram of antigen processing with MHC class 1

Answer 8

10.4.docx

Question 9

Where does the CD8 domain bind to MHC class 1?

Answer 9

Alpha 3 (bottom left yellow)

Question 10

Where does CD4 bind to on MHC class 2?

Answer 10

Beta 2 (bottom right light)

Question 11

WHat are the two receptor components that bind to MHC on both CD8 and CD4 T cells?

Answer 11

Alpha TCR and Beta TCR

Question 12

In what situations is MHC class 1 useful? What happens when the antigen is presented?

Answer 12

Useful for intracellular pathogens/tumour. Leads to production of cytotoxic T cell

Question 13

In what situations is MHC class 2 useful? What happens when the antigen is presented?

Answer 13

Useful for extracellular pathogens. Leads to production of helper T cells.

Question 14

Draw an immunoglobulin, label the chains, disulphide bonds, and antigen binding sites

Answer 14

10.4.docx

Question 15

What are the five types of immunoglobulin

Answer 15

GAMED

Question 16

Which is the first Ig to be secreted? Where can it bind to antigens?

Answer 16

• IgM
• Binds to antigens in blood and tissue

Question 17

Draw the structure of IgM. Describe it’s structure

Answer 17

Check diagram (+ “pentameric; 10 antigen binding sites”)

Question 18

On what encounter with an antigen is IgG secreted more?

Answer 18

Second encounter (B cell changes from IgM to IgG, refining itself in the process)`

Question 19

Draw an IgG molecule and list off as many facts about is as you can

Answer 19

10.4.docx

Question 20

Which receptors do IgG antibodies bind to?

Answer 20

Fc receptor on amcrophages and neutrophils

Question 21

Why is sIgA called sIgA?

Answer 21

SECRETORY:
In mucosal secretions. Binds to antigens. Secretory component prevents it from breakdown by enzymes, giving it time to bind

Question 22

Is IgA monomeric or dimeric? Therefore, how many binding sites does it have?

Answer 22

Dimeric, four binding sites

Question 23

Draw sIgA

Answer 23

10.4.docx

Question 24

Draw a flow chart of B cell maturation

Answer 24

10.4.docx

Question 25

What sites do antibodies bind to on antigens?

Answer 25

Epitopes

Question 26

raw the eq rxn for agab complex formation

Answer 26

Ab + Ag <> AbAg complex

Question 27

What are the four functions of antibodies

Answer 27

- Neutralisation - Agglutination - Opsonisation (FcR -> enhances activation) - Classical Complement Activation (punching hole)

Question 28

What is "specificity" of B cells?

Answer 28

when one b cell will specifically bind to one antigen

Question 29

What happens after a B cell is activated? What is this called?

Answer 29

It proliferates itself in multiple rounds (this is known as clonal proliferation)

Question 30

What do B cells differentiate into following clonal proliferation?

Answer 30

- Memory B cells expressing IgG - Plasma cell (secretes IgM antibodies)

Question 31

What Ig isotype is on undifferentiated b cells?

Answer 31

IgM

Question 32

What Ig isotype do plasma cells from differentiated memory cells produce?

Answer 32

IgG

Question 33

Draw a Primary antibody graph including IgM and IgG

Answer 33

10.4.docx

Question 34

List the four steps in the initial humoral response

Answer 34

- Recognition - Activation - Clonal proliferation - Differentiation

Question 35

Draw a secondary antibody graph including IgM and IgG

Answer 35

10.4.docx

Question 36

Draw a flow chart of T cell development, including where each step occurs

Answer 36

- Haemoatopoietic Stem Cell differentiates into common lymphoid progenitor in bone marrow - CLP enters travels through circulation to thymus - Here is becomes a lymphoid progenitor cell - Pre T Cells - Mature Naive CD4 and CD8 T cells - Circulation again

Question 37

What is clonal selection?

Answer 37

The process by which one T cell is activated upon recognition of a complementary antigen

Question 38

Draw a flowchart of T cell activation into effector cells

Answer 38

10.4.docx

Question 39

Describe the role of helper T cells in activating B cells

Answer 39

- B cells present antigen to Th via MHC 2 - Th release cytokines to activate B cell

Question 40

Describe the role of helper T cells in activating macrophages

Answer 40

Releases cytokines to: - Increase phagocytotic activity - Increase experssion of MHC II (extracellular)

Question 41

After they leave the secondary lymphoid tissues, what local vascular changes permit Tc, Th and Ig from leaving the bloodstream? Can they leave otherwise?

Answer 41

- Vasodilation - Increased vascular permeability - No, they cannot leave otherwise

Question 42

Describe the mechanism by which Tc kill inflected cells via apoptosis

Answer 42

- Recognises unusual cell and forms an enclosed seal (with a gap) - Perforins and granzymes released from granules - Perforins perforate, creating channels through which granzymes travel - Granzymes initiate apoptosis

Question 43

Which types of cells are involved in antibody-dependent cell cytotoxicity?

Answer 43

- Neutrophils - Macrophaghes - NK cells - Eosinophils