Lecture 17 - Lymphocyte Development - B Cells Flashcards Preview

Immunology > Lecture 17 - Lymphocyte Development - B Cells > Flashcards

Flashcards in Lecture 17 - Lymphocyte Development - B Cells Deck (32):
1

Where do B cells mature in birds?

Bursa of fabricus

2

Where do B cells mature in humans?

Bone marrow

3

State of BCR in an immature B cell

Fully mature BCR

4

Why are there fewer BCR expressed than possible gene rearrangements?

V(D)J recombination is not completely random, hence why there are ~10^6 expressed BCR, and 10^11 theoretical combinations of V(D)J genes

5

From what do all lymphocytes arise?

Uncommitted progenitors

6

Granulocytes arising from granulocyte myeloid progenitor
1)
2)
3)
4)
5)

1) Neutrophil
2) Eosinophil
3) Basophil
4) Monocyte
5) Unknown mast cell precursor

7

Is the multipotent progenitor self-renewing?

No

8

Function of stromal cells

Secretes factor essential for B cell maturation

9

Stromal cell location

Bone marrow

10

Where in the bone marrow is the multipotent progenitor?

Endosteum

11

How is B cell development location-dependent?

Stromal cells secrete different factors required for B cell development in different places in the bone marrow.

B cells become more mature as they move from the endosteum into the central sinus

12

When is the heavy mu chain produced?

Recombined in pre-pro and pro B cells
Expressed on pre-B cells
Pre-B cells that don't produce mu chains die

13

What induces surrogate light chain assembly?

E2A-induced lambda 5

14

Components of the surrogate light chain

VpraB, Igalpha, Igbeta, SLC

15

How does signalling through the pre-BCR occur?

Pre-BCR dimerisation/oligomerisation

16

Important enzyme in pre-BCR signalling

Bruton's tyrosine kinase

17

Interleukin that is essential for B cell development

IL-7

18

What happens at the conclusion of heavy-chain rearrangement?

Pre-b cell large expands 30-60-fold before transitioning to resting pre-B cell small

19

Consequence of expansion of pre-B cell large before transitioning to small

Large number of pre-B cell small with identical heavy chains

20

What is a B cell only being able to express kappa or lamba light chain called?

Isotypic exclusion

21

What happens in the transition between pre-B cell small and immature B cell?

IgM is expressed

22

Is antigen needed for pre-BCR to be engaged?

No

23

Number of attempts at heavy chain recombination

Two
Because of allelic exclusion

24

Number of attempts at light chain recombination

Four
Because of allelic exclusion and kappa and lambda loci

25

When does Bruton's X-linked agammaglobulinaemia present?

~3 months after birth

26

RAG expression during B cell development

Two peaks
1) Early pro-B cell
2) Pre-B cell

27

What ensures that a B cell can only make one type of antibody?

Allelic exclusion

28

Negative selection/Clonal deletion

If an immature B cell encounters a strongly-cross-linking antigen in the bone marrow

Only self antigens should be in the bone marrow

29

What can save an immature B cell from clonal deletion?

RAG is still active at the stage of immature B cell, and can initiate receptor editing

30

Stages of B cell development where heavy chain locus is rearranged

Early, late pro-B

31

Stage of Bc ell development where light chain locus is rearranged

Pre-B

32

Signals without which immature B cells will die

Positive signals