Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micro FINAL EXAM > Antigen processing, presentation & Co- stimulation > Flashcards

Antigen processing, presentation & Co- stimulation Flashcards

1
Q

CD8+ T cells are _______ restricted and recognize ________ proteins.

A

MHC I

Cytosolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

CD4+ T cells are _______ restricted and recognize _______ and _______ pathogens.

A

MHC II

Extracellular & Intravesicular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 steps of lymphocyte activation?

A
  1. Microbe infects host
  2. microbe is taken up by APC (antigen presenting cell) at site of infection
  3. APC enters lymph circulation and into Lymph node
  4. Naive T and B cells enter Lymph node from circulation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

_______ is central to the development of immune response.

A

Antigen presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Antigen presentation?

A

It is the bridge between recognition and full blown immune response.
- Enables T cell-mediated killing, or augments antibody production by B cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

True or false, antigen presentation is context dependent?

A

True! deploys different immune responses under different circumstances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Antigen presentation is modulated by _________.

A

Co-stimulatory molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Successful antigen presentation results in what?

A

Activation of T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the most effective Antigen presenting cells for initial T cell activation?

A

Dendritic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

_________ must be activated by phagocytes before presenting antigens.

A

Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

_______ may be the major type of antigen presenting cell for secondary immune response.

A

B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can happen if antigen recognition occurs without antigen presentation?

A

Tolerance = not good!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the “professional” APC?

A

dendritic cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

True or false, Dendritic cells, B & T cells are the only APC’s.

A

False!

- All nucleated cells can present endogenous antigen in association with MHC I molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the two pathways of antigen presentation?

A

Pathway 1 = Exogenous antigens presented to T helper cells.

Pathway 2 = Endogenous antigens presented to CD8+ T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define antigen processing…

A

process of antigens being digested and placed of surface with correct MHC molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the steps of the Endogenous antigen Cytosolic pathway?

A
  • Proteins to be degraded are tagged by ubiquitin
  • Degradation of ubiquitin-protein complexes occur within the central channel or proteasome.
  • Peptides generated are transported into the Lumen of RER by TAP’s
  • Newly synthesized MHC within RER membrane binds to antigen peptide.
  • Antigen-MHC I complex released and transported to the cell.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the steps of the Exogenous antigen Endocytic pathway?

A
  • Antigens are internalized in endosomes
  • They are digested first in the endosomes, then in lysosomes to 13-18 aa peptides.
  • Class II molecules are produced at RER
  • They are associated with the invariant chain protein, preventing their binding to endogenous antigens.
  • Class II-Ii complex move into endocytic compartments
  • Ii will be digested to a short fragment (CLIP)
  • HLA-DM triggers the exchange of CLIP and antigen peptide.
  • HLA-DO block the activity of HLA-DM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

_____ is two distinct polypeptides, an alpha and a beta.

A

MHC II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

______ is one alpha peptide.

A

MHC I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a haplotype and what does it influence?

A

a cluster of alternative form of same gene, closely linked on same chromosome. Influences:

  • How individual responds to pathogens
  • Susceptibility to certain diseases
  • Transplant success
22
Q

MHC genes are highly polymorphic…. what does this mean?

A
  • Hundreds of alleys in humans apron. 10^13 combinations (This is why its hard to match ppl for transplants, even 1st relatives often differ.)
23
Q

MHC alleles are _______ expressed.

A

concomitantly

24
Q

Self MHC + foreign AG = ?

A

T cell response

25
Q

Self MHC + Self Ag = ?

A

No response

26
Q

MHC expression can be induced on almost every nucleated cell in the body….True or False?

A

True

27
Q

______ is a key factor in determining tissue matching for a transplant donor and recipients.

A

MHC

28
Q

True or false, MHC molecules have very limited specificity.

A

False, its very broad!

29
Q

MHC molecules have a ______ on/off rate.

A

slow

30
Q

True or false, MHC molecules discriminate self from foreign peptides.

A

False, it does not!

31
Q

What determines which peptides bind and how they bind?

A

The MHC haplotype of an individual

32
Q

What is MHC Restriction?

A

Allows individual cells to recognize foreign Ag displayed on the surface of an individual APC.
*Allows T cells to distinguish between self and non-self & prevents destruction of Non-self.

33
Q

What is the basic definition of Antigen presentation?

A

Process by which MHC-antigen interact with T helper or T cells.

34
Q

What are the steps of Antigen Presentation?

A
  1. MHC-peptide complex binds to the T cell receptor (TCR)
  2. CD4 interacts with both MHC II on APC and TCR on T cell to strengthen antigen-TCR interaction.
  3. CD8 interacts with both MHC I on target cell and TCR on T cells.
  4. Co-stimulatory molecules B7 on APC binds to its T cell ligand CD28.
  5. Adhesion molecule ICAM-1 on the APC binds to its T cell ligand LFA-1.
35
Q

Expression of the ______, _______ and _______ are required for antigen recognition and signaling.

A

TCR, CD3 and “the squiggly line”

36
Q

CTLA-4 can competitively inhibit ______ binding to _____.

A

CD28 to CD28

37
Q

CTLA-4 when bound to B7 will actively block signals from the _____ and from _____.

A

TCR and CD28

38
Q

What happens during the absence of a antigen-TCR interaction?

A

T cell will not be stimulated.

39
Q

What happens during absence of co-stimulatory molecules?

A

T cells will not be stimulated.

40
Q

T-cells need the Co-reception of what two signal to become activated?

A
  1. Co-stimulatory molecules

2. Antigen-TCR interaction

41
Q

What happens (to CD28) at the the termination of the Immune response

A

CD28 is replaced by CTLA-4 and down regulates T-cell function.

42
Q

What 6 things happen after antigen presentation?

A
  1. activation of tyrosine kinases associated with TCR/CD4(8) complex.
  2. Activated Tk phosphorylate cytoplasmic tails of the clustered receptors.
  3. Atctivation of kinase cascade follows.
  4. Activation of Transcripton factors.
  5. Induction of IL-2 and IL2R.
  6. Cell division after IL-2 ligation to IL-2R.
43
Q

What role does the IL-2 receptor (IL-2R) have in T cell response?

A

It amplifies the T-cell response.

44
Q

Before activation the T cells express what?

A

Beta, gamma IL-2R

45
Q

After activation the T cells, IL-2R takes what form and does what?

A

Alpha, beta, gamma IL-2R

and enhances the affinity of T-cells by 1000 fold.

46
Q

IL-12 drives the development of ____.

A

Th1 cells

47
Q

IL-4 drives the development of _____.

A

Th2 cells

48
Q

Th1 cells do what?

A

Provide help for cell mediated immune responses.

49
Q

What are 2 of the most important Th1 cytokines?

A

IFN-gamma & IL-4

50
Q

What do Th2 cells do?

A

Provide help for humoral immune responses

51
Q

What structure is responsible for the fixation of avian limb structures in a lipid saturated carbohydrate membrane?

A

The KFC

Micro FINAL EXAM (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions