Dendritic cells and antigen presentation

Question 1

immature dendritic cells are

Answer 1

good at phagocytosis but bad at presenting antigens

Question 2

MHC I in the

Answer 2

cytosol

Question 3

MHC II in the

Answer 3

endosomal compartment

Question 4

MHC I on

Answer 4

all cells

Question 5

MHC II on

Answer 5

APC, B cells and macrophages

Question 6

activation of immature dendritic cell

Answer 6

1) PRR e.g. TLR4 recognise LPS
2) DC matures and prepares to become an APC
3) peptide anti from invading bacteria, regionally extracellular, are endocytosided
4) combine with MHC II
5) then this complex is presented on the cell surface
6) also increase in costimualtory molceules

Question 7

costimulatory moleucles

Answer 7

CD80/86 increase

Question 8

immature DCs are located i the

Answer 8

tissues throughout the body, including skin, git, respiratory tract

Question 9

encounter with a pathogen induces

Answer 9

the DC to matute

Question 10

T cells express which co receptors

Answer 10

CD8 -MHC I

CD4- MHC II

Question 11

what stimulates Th17

Answer 11

IL-6

Question 12

what does Th17 produces

Answer 12

IL-17 and IL-6 –> neutrophil recruitment

Question 13

MHC II –>

Answer 13

CD4 T cell- T helper cell

Question 14

MHC I –>

Answer 14

CD8 T cell- cytotoxic T cell

Question 15

each T cell only has one

Answer 15

TCR which specific to pathogen

Question 16

DC presentation to CD4 T cell

Answer 16

1) T cell receptor binds to MHC II peptide molecule
2) CD4 receptor on T cell binds to MHC II complex
3) CD28 (T cell) binds to CD 80/86 costimulatory molecules

Question 17

cytokine help Th cells decide

Answer 17

which subclass to differentiation into

Question 18

what stimulates Th1

Answer 18

IL-12

Question 19

what stimulates Th2

Answer 19

IL-4

Question 20

Th1 release

Answer 20

IFN-Y AND TF-A

• macrophages
• cytotoxic T cells

Question 21

Th2 release

Answer 21

IL-4, IL-5 and IL-13

• B cell activation
• allergic respomse

Question 22

B cells reconginise

Answer 22

intact antgins

Question 23

T cells recognise

Answer 23

fragments of protein antigen - degraded inside APC

Question 24

antibodies can act

Answer 24

far away- humoral

Question 25

T cells ave a

Answer 25

short range effect

Question 26

cytotoxic T cells

Answer 26

directly kill virally infected cells and other cells infected with intracellular pathogens

Question 27

T helper cell

Answer 27

helps stimualtemacrophages, B cells and cytotoxic t cells

Question 28

CD8 and CD4 cells must be

Answer 28

activated to proliferate and differentiate into effector cells

Question 29

main types of APC

Answer 29

macrophages DC and B cell

Question 30

cytotoxic T cells protect against

Answer 30

intracellular pathogens- sheltered from antibodies

Question 31

CD8 T cell activation

Answer 31

• once activated by APC (MHC I), CD8 T cells become effector T cells- will kill any target cell infected with same pathogen
• once bound to the target cell, CD8 T cell will release a pore-forming protein called perforin
• this mediates entry of granzymes into target cell
• mediated apoptosos

Question 32

apoptosis by Cytotoxic T cell

Answer 32

Target cell which presents antigen on MHC I

• perforin binds and facilities entry of grnazymes into cell via pores
• granzymes cleave BID, causing cytochrome C to release from mitochondria into cytosol
• cytochrome C activates pro-caspase 3
• pro-caspase 3 cleave ICAD- inhibitor of CAD
• CAD degrades DNA ensuring cell death