Brainscape's Knowledge GenomeTM

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


See full index

CRG RUSVM Immunology > lymphocytes and their receptors > Flashcards

lymphocytes and their receptors Flashcards

1
Q

what are lymphocytes important for

A

lymphocytes are important for the adaptive immune response

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

what are the 3 major types of lymphocytes

A
  • T lymphocytes (T cells)
  • B lymphocytes (b cells)
  • NK cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the function of T lymphocytes (t cells)

A

t cells regulate adaptive immunity are responsible for cell-mediated immune responses

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

what is the function of the B cells

A

B cells are responsible for antibody production

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

what is the purpose of the NK cells

A

NK cells that play a role in innate immunity (LGL, large granular lymphocytes)

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

what is the morphology of lymphocytes

A
  • lymphocytes are small round cells, T to 15 microns in diameter
  • Have a large round nucleus
  • the nucleus is surrounded by a thin rim of cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

when does T cell development begin

A

T-cell development begins well before birth

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

Pre-T cells leave the bone marrow and migrate to the ______ and are called _______

A

Pre-T cells leave the bone marrow and migrate to the Thymus and are called Thymocytes

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

what are the two types of t cells that form when the t cell receptors begin to form

A
  1. alphabeta T-cell
    1. t cells that express the beta chain
  2. Gammadelta T cell
    1. cells that express gamma or delta chain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Complementarity between the antigen and the TCR dictates the

A

specificity of a response

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

what is an epitope

A

one TCR for one antigen

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

how many genes do humans have

A

20,000

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

what allows the TCR to recognize different antigens eventhough they are epitope

A

Random rearrangement of germline gene segments encoding TCR components

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

is the random rearrangement of the germline gene unique to T cells

A

No this feature is also shared with B cells

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

where does the germline gene segment rearrangement take place

A

takes place in the thymus

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

are the genes that encode for the alpha and beta chains for TCR contiguous?

A

no they are not contiguous

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

what are the segments in the different regions of DNA labeled as (there are 4)

A
  1. Variable
  2. Joining
  3. Diversity
  4. Constant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is the alpha or beta chain the first to undergo rearrangement of TCR gene rearrangement

A

Beta chain

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

what are the steps for the Beta chain rearrangement

A
  1. Random joining of a Dbeta and Jbeta gene segment
  2. Random linking of the new DJbeta segment with a Vbeta segment
  3. Formation of the variable region of the beta chain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the steps for the alpha chain TCR gene rearrangement

A
  • Valpha and Jalpha gene segments are joined to make a complete alpha-chain variable region
  • Then VJalpha segment is joined with a Calpha region segment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the two genes that make rearrangement of the segments possible

A
  1. recombination activating gene 1 and 2
    1. RAG1
    2. RAG2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Enzymes such as _________, excise the intervening DNA to increase diversity of the TCR

A

Enzymes such as DNA dependent protein kinase, excise the intervening DNA to increase diversity of the TCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the two steps called for sorting and selecting T cells that takes place in the thymus

A
  • positive selection
  • negative selection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is positive selection

A

a test of whether a newly created TCR can bind to the MHC 1 or MHC 2 on thymic cortical epithelial cells (APCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

how does a T cell pass the positive selection

A

the T-cell should bind the MHC in order to pass the positive selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how does a T cell fail the positive selection

A

if a T cell does not bind the MHC, it fails the positive selection and is eliminated by apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why is the positive selection of the T cells used

A
  • eliminates thymocytes that:
    • have failed to assemble a TCR
    • or have assembled a useless TCR
  • Also the commitment of T cells to either a CD4+ or a CD8+ lineage
28
Q

what percentage of cells can fail positive selection and undergo apoptosis

A

as much as 96%

29
Q

What is negative selection of T cells

A

if a T cells TCR binds with high affinity to an MHC-antigen complex present on an APC, the T cell dies through apoptosis

30
Q

What does negative selection eliminate

A

negative selection eliminates most thymocytes that react with self as represented in the thymus

31
Q

do early thymocytes have CD4 and CD8 receptors and what are these cells called

A
  • no early stage thymocytes lack CD4 and CD8
  • they are known as double-negative cells
32
Q

when are CD4 and CD8 expressed and are subsequently known as

A

CD4 and CD8 are expressed once the alphabeta TCR is expressed: these cells then become double positive T cells

33
Q

what is the difference between immature and mature T cells in their expression of CD4 and CD8

A
  • Immature cells express both CD4 and CD8 (double positive T cells)
  • Mature T cells express only CD4 or CD8 (single positive)
34
Q

How is a T cell chosen to express CD8

A

if the TCR has an affinity for an MHC 1 , the thymocyte turns off the CD4 gene and begins to express CD8 solely

35
Q

How is a T cell chosen to express CD4

A

If the newly formed TCR has affinity for MHC class 2 molecules that lymphocyte switches of the CD8 gene and expresses only CD4

36
Q

how do cells that have passed both positive and negative selection leave the thymus

A

via the blood

37
Q

what do CD8+ T cells become

A

cytotoxic T cells

38
Q

what do CD4+ T cells become

A
  • helper T cells
    • eventually differentiating into Th1, Th2, Th17 etc after antigen encounter
  • Some CD4+ T cells differentiate into regulatory T cells
39
Q

Why is the AIRE (autoimmune regulator gene) important

A

allows thymic epithelial cells to express many of the proteins usually found in other tissues of the body

40
Q

what are the major groups of receptors on T cells

A
  1. TCR: antigen receptor
  2. Cytokine receptors
  3. antibody receptors
  4. complement receptors
  5. adhesion molecules
  6. Regulatory receptors
  7. Transport receptors
  8. chemokine receptors
41
Q

what are the three stages of B lymphocyte development

A
  1. Maturation
    1. generation of mature immunocompetent B lymphocytes
  2. Activation
    1. contact of B lymphocytes with specific antigens
  3. Differentiation
    1. activation of B cells become plasma cells that produce antibodies or become memory B cells
42
Q

where do By lymphocyte develop in most vertebrates

A

in the bone marrow

43
Q

during prepaturition where do b lymphocytes developed

A

yolk sac, fetal liver, bone marrow

44
Q

where does b lymphocyte development take place post parturition

A

bone marrow

45
Q

what are progenitor cells (Pro-B)

A

cells that differentiate from lymphoid precursor cells into B lymphocytes

46
Q

when do Pro-B cells differentiate into B lymphocyte precursor cells

A

when the cells are in the presence of IL-7 and bone marrow stromal cells

47
Q

what first appears on the pro-B cells

A
  1. heavy chains (H)
    1. followed a V S J rearrangement and further alpha and beta chains of poly-Ig
  2. Light chains are rearranged at the pre-b cell stage
48
Q

what types of light chains are expressed on pro-b cells

A

because of the allelic exclusion only one type of light chain can be expressed (V J) K or gamma

49
Q

after the pre B stage where H chain undergoes V, D, J rearrangement and the light chain has V and j Rearrangement what cell stage is the b cell in

A

immature b cell

50
Q

what do the membrane-bound IgM and Igalpha/beta chains form

A

these proteins form the b lymphocyte cell receptor complex (BCR)

51
Q

what two recombinases regulate the chain rearrangement in B cells

A

RAG1 and RAG2

52
Q

what happens if the BCR on an immature B cell is stimulated

A

this would lead to cell death or anergy (lack of response)

53
Q

when is full maturity of B cells attained

A

when membrane bound IgD is expressed

54
Q

what must happen in order for IgD to be expressed on the membrane of the B cell

A

This requires a change in RNA coding to allow coding of both heavy chains ( mu and delta (IgM and IgD))

55
Q

what percentage of b cells produced in the bone marrow daily reach circulation

A

10%

56
Q

what happens to the b cells that do not make it to circulation

A

eliminated through negative selection or clonal deletion

57
Q

Why would negative selection of clonal deletion eliminate B cell

A

these methods eliminate B cells that have high affinity for self-antigens

58
Q

what happens to the B cells that enter circulation and arrive at the periphery

A

they undergo activation and differentiation into plasma cells

59
Q

how many polypeptide chains do the B cell receptors have

A

4 polypeptide chains

60
Q

the 4 polypeptide chains of B cell receptors make up

A

2 identical heavy chains and 2 identical light chains

61
Q

how are the light chains bound to the heavy chains in the B cell receptor

A

disulfide bonds

62
Q

how are the H chains bound to each other in the b cell receptor

A

they are bound similarily to the Light chains with disulfide bonds

63
Q

what is important about the C-terminal of the H chain that spans the cell membrane

A

they are identical for each Ig isotype

64
Q

what is important about the N terminal (membrane-distal) portions of the H chains

A

they are highly variable

65
Q

what is the similarity of the N-terminal portions of the H and Light chains

A

both N terminal portions of L and H are highly variable

66
Q

what are Igalpha/IgBeta

A

signalling molecules

67
Q
A

CRG RUSVM Immunology (8 decks)

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