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Micro/Immuno Exam 1 > Lecture 3 - Antigen Processing and Presentation (Stiner) > Flashcards

Lecture 3 - Antigen Processing and Presentation (Stiner) Flashcards

1
Q

Which cells are professional antigen presenting cells (APCs?

A

Dendritic cells
Macrophages
B cells

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2
Q

Which MHC do most nucleated cells in the body use to present antigen?

A

MHC 1

This is important in cancer b/c cytotoxic T-cells can see antigens presented in the context of MHC 1

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3
Q

What are the two pathways of Antigen presentation?

A
  1. EXOgenous

2. ENDOgenous

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4
Q

Which pathway involves MHC ii and T-helper cells?

A

EXOgenous

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5
Q

Which pathway involves MHC I and cytotoxic T- cells?

A

ENDOgenous

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6
Q

What are the two pathways for antigen PROCESSING?

A
  1. Cytoplasmic Pathway (for endogenous antigens, recognized by CD8+ T cells)
  2. Endocytic Pathway (for exogenous antigens, recognized by CD4+ T cells)
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7
Q

Which antigen processing pathway uses proteasomes to break down cytoplasmic proteins?

A

Cytoplasmic pathway (for endogenous antigens recognized by CD8+ T cells)

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8
Q

Which antigen processing pathway uses lysosomes to break down endocytic proteins?

A

Endocytic pathway (for exogenous antigens recognized by CD4+ T cells)

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9
Q

***How does an MHC molecule make it from the ER (site of synthesis) to the cell membrane?

A
  1. MHC is associated with an INVARIANT CHAIN that keeps it from binding to anything.
  2. It is carried in an endosome.
  3. Invariant chain is digested, and now CLIP hangs out in the binding site of MHC.
  4. HLA-DM reMoves CLIP from MHC binding site, and MHC moves to cell surface.
    * **HLA-DO blOcks HLA-DM & therefore keeps CLIP in binding site & MHC off cell surface.
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10
Q

How are MHC I and MHC II different?

A 
MHC I 
   -small
    -made of one protein
    -antigen binds only to the END of MHC I
MHC 2
    -wider
    -made of two proteins
    -antigen binds ALONG LENGTH of MHC II
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11
Q

What can an MHC haplotype influence? (3)

A
  1. response to pathogens
  2. susceptibility to certain diseases
  3. transplant success
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12
Q

What is an MHC haplotype?

A

The set of MHC alleles on an individual chromosome

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13
Q

Do MHC molecules discriminate from self and non-self?

A

No, they have a broad specificity for peptides.

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14
Q

What is needed for a CD8+ T-cell to become activated? Two signals.

A
  1. Primary stimulus
    • T-cell receptor bind to MHC I on APC
  2. Secondary stimulus
    • CD28 on T cell binds to B7 on APC
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15
Q

Where is B7 located?

A

on an APC presenting to a CD8+ T cells

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16
Q

Where is CD28 located?

A

on a T-cell that is getting info from an APC. CD28 connected to APC’s B7

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17
Q

What are the adhesion molecules involved in the CD8+ activation?

A

ICAM-1 on APC binds to LFA-1 on T cell

18
Q

Where is ICAM-1 found?

A

on APC presenting to CD8+ cell.
Adhesion molecule.
ICAM-1 binds to LFA-1

19
Q

Where is LFA-1 found?

A

on CD8+ T cell getting info from an APC cell.
Adhesion molecule.
LFA-1 binds to ICAM-1

20
Q

What is the order of events during CD8+ activation?

A
  1. Adhesion (LFA-1 binds to ICAM-1)
  2. Ag-specific activation (TCR binds to MGC I)
  3. Costimulation (CD28 binds to B7)
21
Q

What type of proteins to CD8+ T cells recognize?

A

cytosolic proteins

22
Q

What type of proteins to CD4+ T cells recognize?

A

extracellular and intravesicular proteins

23
Q

What are the 3 components of TCR?

A
  1. TCR
  2. Zeta chains
  3. CD3
    (CD3 and zeta chains are required for signaling.)
24
Q

What costimulatory receptor binds to B7 on APCs during T-cell activation?

A

CD28 on T cell surface

25
Q

What receptor replaces CD28 on T cell surface once in the infection has been taken care of? We need to downregulate T cell activity.

A

CTLA-4 is now on the surface of the T cell. It also binds with B7 on APC

26
Q

***What is the primary cytokine that T cells produce?

A

IL-2

27
Q

What does the T-cell produce when it is activated?

A

IL-2

28
Q

How does IL-2 amplify the T-cell response?

A

Adds an alpha segment to IL-2R, and therefore increases its affinity by 1000-fold

29
Q

What does IL-2 do, and why is it so potent?

A
  1. T cell clonal expansion, differentiation into effector and memory cells
  2. regulatory T cell development, survival, and function
  3. NK cell proliferation, increased cytotoxic activity
30
Q

What is the costimulatory signal that B cells need from T cells to be activated?

A

CD40 (on B cell) binds to CD40L (on T-cell)

31
Q

Where is CD40?

A

B cell

32
Q

Where is CD40L?

A

T cell

33
Q

Which interleukin drives the development of TH1 cells?

A

IL-12

34
Q

What does IL-12 do?

A

drives development of TH1 cells

35
Q

What does IL-4 do?

A

Drives the development of TH2 cells

Potent inhibitor of TH1 response.

36
Q

What interleukin drives the development of TH2 cells?

A

IL-4

37
Q

What do TH1 cells help with?

A

cell-mediated immune responses

  1. activate macrophages
  2. complement antibodies and produce antibodies
  3. activate neutrophils
38
Q

What to TH2 cells help with?

A

humoral immun responses (antibody)

39
Q

Which TH cell makes IFN-gamma?

A

TH1

40
Q

What cytokine does TH1 make?

A

IFN-gamma

41
Q

What does TH2 make?

A

IL-4

42
Q

What TH cell makes IL-4?

A

TH2

Micro/Immuno Exam 1 (10 decks)

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