Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

UBC Microbiology 212 > Immunology Chapter 4 > Flashcards

Immunology Chapter 4 Flashcards

(53 cards)

Start Studying
1
Q

The adaptive immune system uses

A

Antibodies for extracellular threats
T cells for viruses and bacteria inside the cell

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

Precursor T cells are derived from

A

Common lymphoid precursor cells (CLP) in the bone marrow

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

The precursor T cells migrate from the bone marrow to where, and to what?

A

to the thymus, to continue their maturation and start to express TCR and other proteins

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

What is the TCR, and what is it made of

A

a membrane-bound receptor ONLY found on T cells, it’s made up of alpha and beta chains

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

the alpha and beta chains of TCR is held together by

A

disulfide bond

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

Function of CD4 T Helper Cells

A

recognize peptides presented on MHC Class II proteins

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

Function of CD8 T killer cells (CTL)

A

recognize peptides presented on MHC Class I proteins

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

T cells recognize and respond to antigens via

A

TCR complex

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

Expression of the TCR involves….

A

rearrangement of TCR gene segments to form a complete gene

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

What types of infections are T cells especially important for?

A

Viral infections and intracellular bacterial infections (Mycobacterium tuberculosis)

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

Do T cells secrete their TCRs?

A

No, TCRs are only membrane-bound

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

What regions make up each TCR chain?

A

1 Variable (V) and 1 Constant (C)

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

What does the variable region of the TCR do

A

form antigen-binding site

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

How many TCRs are on the surface of one T cell?

A

30,000 identical TCRs

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

What proteins are part of the full TCR Complex

A

TCR α and β chains,
CD3 complex (signaling),
and CD4 or CD8 (accessory).

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

What is the role of TCR α and β chains

A

for antigen recognition

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

The Vα and Vβ chains regions combine to form the

A

antigen binding site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the role of Co-receptor CD4 (T helper) or CD8 (CTL)

A

strengthens interaction between APC and T helper cell
CD4 recognize MHC II
CD8 recognize MHC I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the role of CD3 (multiple subunits)

A

interact with signalling proteins to send a signal to the nucleus saying that the TCR has been engaged, resulting in proliferation and new gene expression

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

What type of antigens do TCRs recognize

A

Processed peptides presented on MHC proteins

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

If the host is healthy, then the peptide if from a

A

self-protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

If there is an infection, the peptide is derived from a

Study These Flashcards
A

pathogen protein

23
Q

What are thymocytes

Study These Flashcards
A

Immature T cells developing in the thymus

24
Q

What must happen for a thymocyte to survive

Study These Flashcards
A

It must express functional TCR

25
the development of t cells in the bone marrow
HSC --> CLP --> T cell precursor (TCR-) (-) means that the protein is not made
26
the development of t cells in the thymus
T cell precursor (TCR-) --> Thymocyte (TCR+)(CD4-)(CD8-) ---> Thymocyte (TCR+)(CD4+)(CD8+)
27
What does it mean when CD4 and CD8 is (-)
it means they are committed to T cell development, but they don't express the receptors yet (has to be +)
28
How does the T cell know whether it should be a helper T cell or CTL
they undergo positive and negative selection
29
The TCR interaction with the MHC determine whether the...
thymocyte matures to become a CTL or T helper cell
30
is CD4+CD8+ a mature thymocyte
no it's immature
31
what is CD4+CD8- and what does it express
it's a mature thymocyte and it expresses CD4
32
what is CD4-CD8+ and what does it express
it's a mature thymocyte and it expresses CD8
33
What happens during positive selection
Thymocytes that weakly bind MHC presenting self-peptides are selected to survive needs to have low affinity they can't be too strong
34
What happens to thymocytes that cannot bind to MHC at all?
they undergo apoptosis
35
who are the graders for positive selection
thymic cortical epithelial cells
36
who are the graders for negative selection
macrophages and dendritic cells form the macrophages thymic medullary epithelial cells (via AIRE gene) they are tough graders
37
What is the goal of negative selection
to see which T cells bind to MHC w self-peptide too tightly
38
why do we want to get rid of the ones that bind too tightly
because it can activate a lymph node / spleen and cause autoimmune disease
39
What does the AIRE gene do?
promote expression of many tissue-specific antigens in the thymus allows negative selection against tissue specific antigens so you don't have T cells attacking your heart, kidney, islet cells
40
Thymocyte X DID NOT bind to MHC I + self peptide with a high enough affinity to activate the cell. What is the fate of thymocyte A
Pass, gets a survival signal!
41
T cells are not self-reactive because
its TCR did not interact with MHC Class I + self peptide strong enough to activate the T cell
42
What is the result of positive and negative selection?
less than 5% of thymocytes mature into T cells
43
Why is thymic selection important?
it makes sures the T cells can recognize MHC and are not self-reactive
44
AIRE gene is expressed in
thymic medullary epithelial cells
45
when does the first round of negative selection occur and which cells perform it
it occurs simultaneously with positive selection carried out by thymic medullary epithelial cells
46
What type of antigens are involved in the first and second rounds of negative selection
housekeeping proteins
47
which cells carry out the second round of negative selection
bone marrow-derived macrophages and dendritic cells
48
which cells perform the final (third) round of negative selection
thymic medullary epithelial cells via AIRE gene
49
What is the function of Treg cells
suppress immune responses and prevent autoimmunity
50
when do Treg cells develop
when thymocytes bind self-antigen with moderately high affinity but aren't deleted
51
What marker to Treg cells express highly
CD25 (part of the IL-2 receptor)
52
Where can Treg cells develop
In the thymus (natural Tregs) and outside the thymus (induced T regs)
53
True or False The AIRE gene produce allows medullary thymic epithelial cells to display peptides derived from proteins normally expressed by cell types outside of the thymus environment
True

UBC Microbiology 212 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions