Immune system 2

Question 1

What are interferons?

Answer 1

Cytokines that inhibit viral replication within cells

Question 2

Describe how interferons are activated and their effects

Answer 2

Activated macrophages release IL-12 which stimulates IFNgamma by natural killer cells and lymphocytes

IFNgamma leads to further macrophages activation in feedback loop amplifying innate immune response
Increases phagocytosis and iNOS expression

Question 3

Which cytokines induce endothelial cells to express adhesion molecules allowing neutrophils and monocytes to bind and leave the blood stream

Answer 3

IL-1

TNFAlpha

Question 4

What is the role of IL-8?

Answer 4

Potent neutrophil chemoattractant and activates macrophages

Question 5

What 3 things act on the endothelium to increase permeability?

Answer 5

TNFAlpha
Platelet Activating Factor
PG

Question 6

PAF causes what in relation to platelets?

Answer 6

Causes platelets to release histamine also increases vascular endothelial permeability

Question 7

Define complement

Answer 7

A group of plasma and cell membrane proteins that leads to the formation of a membrane attack complex and inflammation

Question 8

What is the role of complements?

Answer 8

Directly recognises pathogen, insert into membrane results in membrane attack eg holes in the surface
think cell lysis

Question 9

Which cell is part of the humoural response?

Answer 9

B-cell

Question 10

Which cells are part of the cellular immune response

Answer 10

CD4+ T cell

CD8+ T cell

Question 11

Where are T lymphocytes derived from?

Answer 11

Thymus

Question 12

Where are B lymphocytes derived from?

Answer 12

Bursa of Fabricus in mammals the bone marrow

Question 13

What do B lymphocytes produce?

Answer 13

AB antibodies known as immunoglobins

Question 14

Describe the humoral response

Answer 14

B cells have B cell receptor, a surface bound antibody
Antibodies are opsonins that bind proteins,sugars and rarely lipids
Facilitate uptake of AG as Ab-Ag complex binds Fc receptors on phagocytic cells

Question 15

Describe the structure of an antibody

Answer 15

Y shaped
2 heavy chains - 50-75kDa
2 light chains-25kDa
Chains linked by disulphide bonds
Hinge region
Fab and Fc portions

Question 16

What is the role of the hinge region on an antibody?

What is it made out of?

Answer 16

Gives the molecule flexibility

Made from prolines breaking the alpha heliex

Question 17

What did antibodies evolve from?

Answer 17

Primordial gene encoding a polypeptide of about 110 amino acids

Question 18

What part of the antibody gives specificity?

Answer 18

N terminal of the Fab portion

Question 19

Which region of an antibody is constant?

Answer 19

The Fc domain

Question 20

What does an antibody bind to?

Answer 20

The epitope- part of an antigen

Question 21

How many amino acids long are epitopes?

Answer 21

8 to 22

Question 22

Define affinity in relation to the antibody-antigen binding

Answer 22

The strength of the interaction between an antibody and antigen

Question 23

Define avidity

Answer 23

The binding of a whole antibody

Question 24

Name the 2 types of antibodies

Answer 24

Monoclonal antibody

Polyclonal antibody

Question 25

Where so monoclonal antibodies come from?

And how many epitopes does it have?

Answer 25

Comes from a single B cell and has a single epitope

Question 26

Where so polyclonal antibodies come from?

And how many epitopes does it have?

Answer 26

Produced by the different B cells and recognises different epitopes

Question 27

Name 3 uses of antibodies in biotechnology

Answer 27

Detection of neutralising antibodies in a patient
Detection of antigens in a virus or a cell
Therapeutics- monoclonal only

Question 28

How many classes of antibody are there?

Answer 28

5

Question 29

Name the 5 Ab classes of antibody.

How are these determined?

Answer 29

IgM
IgG
IgA
IgE
IgD

Determined by the structure of the Fc domain

Question 30

Which antibody class is the most abundant?

Answer 30

IgG

Accounts for 70%

Question 31

The specificity is not related to its class

What does this mean?

Answer 31

Different classes of antibody raised to a target have the same specificity

Question 32

What are the 6 roles of antibodies?

Answer 32

Neutralisation
Agglutination
Opsonisation
Complement Activation
Trigger mast cell degranulation
Activate B lymphocytes

Question 33

Describe how antibodies cause neutralisation

Answer 33

Ab binds to toxins released by the bacteria
Ab can block viral binding proteins
Block the adherence of bacteria to host cells

Question 34

What is opsonisation?

Answer 34

When a pathogen is marked for phagocytosis

Question 35

Describe how a B cell is activated and what it produces

Answer 35

Naive B cell is actiavted and divides into memory cells or plasma cells

Question 36

What is the difference between Memory cells and plasma/effector cells?

Answer 36

Memory cells have a long life span and have the same BCR as parent cells

Plasma cells lived a few days but secrete antibodies

Question 37

Describe clonal expansion/ clonal selection

Answer 37

Antigen binding the particular B cell bound antibody molecules inniates clonal expansion

Produced large number of specific B cells

Antibodies of higher affinity evolve selecting B cells expressing antibodies with high affinity

Question 38

Which antibody is first secreted in clonal selection?

Answer 38

IgM then later class switching

Question 39

What are the roles of the CD4+ T cells?

Answer 39

Immunity against intracellular bacteria and parasites
Provide help to CD8 Tcells
Promotes humoural immune response

Question 40

What are the roles of the CD8+ T cells?

Answer 40

Cytotoxic when activated
Kill virally infected cells
Kill tumour cells

Question 41

Where do all blood borne immune cells originate from?

Answer 41

Hematopoietic stem cells

Question 42

What is haematopoiesis?

Answer 42

formation of blood cells

Question 43

Where does haematopoiesis occur in the 3rd to 7th month of gesteration?

Answer 43

Fetal liver then spleen