Dendritic cells and antigen presentation Flashcards

1
Q

immature dendritic cells are

A

good at phagocytosis but bad at presenting antigens

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2
Q

MHC I in the

A

cytosol

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3
Q

MHC II in the

A

endosomal compartment

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4
Q

MHC I on

A

all cells

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5
Q

MHC II on

A

APC, B cells and macrophages

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6
Q

activation of immature dendritic cell

A

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

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7
Q

costimulatory moleucles

A

CD80/86 increase

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8
Q

immature DCs are located i the

A

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

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9
Q

encounter with a pathogen induces

A

the DC to matute

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10
Q

T cells express which co receptors

A

CD8 -MHC I

CD4- MHC II

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11
Q

what stimulates Th17

A

IL-6

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12
Q

what does Th17 produces

A

IL-17 and IL-6 –> neutrophil recruitment

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13
Q

MHC II –>

A

CD4 T cell- T helper cell

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14
Q

MHC I –>

A

CD8 T cell- cytotoxic T cell

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15
Q

each T cell only has one

A

TCR which specific to pathogen

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16
Q

DC presentation to CD4 T cell

A

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

17
Q

cytokine help Th cells decide

A

which subclass to differentiation into

18
Q

what stimulates Th1

A

IL-12

19
Q

what stimulates Th2

A

IL-4

20
Q

Th1 release

A

IFN-Y AND TF-A

  • macrophages
  • cytotoxic T cells
21
Q

Th2 release

A

IL-4, IL-5 and IL-13

  • B cell activation
  • allergic respomse
22
Q

B cells reconginise

A

intact antgins

23
Q

T cells recognise

A

fragments of protein antigen - degraded inside APC

24
Q

antibodies can act

A

far away- humoral

25
Q

T cells ave a

A

short range effect

26
Q

cytotoxic T cells

A

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

27
Q

T helper cell

A

helps stimualtemacrophages, B cells and cytotoxic t cells

28
Q

CD8 and CD4 cells must be

A

activated to proliferate and differentiate into effector cells

29
Q

main types of APC

A

macrophages DC and B cell

30
Q

cytotoxic T cells protect against

A

intracellular pathogens- sheltered from antibodies

31
Q

CD8 T cell activation

A
  • 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
32
Q

apoptosis by Cytotoxic T cell

A

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