lecture 4 - lymphocyte development

Question 1

where do b cells rearrange their genes

Answer 1

in the bone marrow

Question 2

if the common lymphoid progenitor expressed Pax5 transcription factor it will become what

Answer 2

a b cell

Question 3

what is CD45 is a marker on what cells

Answer 3

B and T cells

Question 4

CD19 is a marker of what cell

Answer 4

B cells

Question 5

what is negative selection

Answer 5

removal of self reactive cells

Question 6

what causes a mature B cell to be activated

Answer 6

when it binds to a foreign antigen

Question 7

activated B cells causes the number of which cells to rise

Answer 7

plasma cells and memory cells

Question 8

where does negative selection of B cells occur

Answer 8

in the bone marrow

Question 9

what does VpreB and λ5 do

Answer 9

bind to heavy chain and make sure its ok and capable of binding a light chain

Question 10

what is the first stage of B cell formation

Answer 10

pro-B cell

Question 11

after V to DJ rearrangement occurs what does the pro-B cell turn into

Answer 11

pre-B cell

Question 12

after light chain rearrangement the pre-B cell turns into an

Answer 12

immature B cell

Question 13

signal that the pre-B cell is ok turns off what genes

Answer 13

RAG 1 and 2 so no more heavy chain rearrangement

Question 14

after the RAG genes are turned off what does the cell do

Answer 14

proliferated a few times

Question 15

then RAG genes come back on for rearrangement of what

Answer 15

light chain

Question 16

D-J rearrangement on both chromosomes then

Answer 16

V - DJ rearrangement on first chromosome

Question 17

if the heavy chain rearrangement is no good you can use the heavy chain rearrangement on

Answer 17

the second chromosome

Question 18

if it fails on both chomosomes the cell

Answer 18

dies

Question 19

if it has passed on the to L chain rearrangement stage, you can attempt to make a light chain on kappa locus if that fails you can try on

Answer 19

lamda locus

Question 20

immature B cells that bind to a self antigen in the bone marrow undergo either

Answer 20

clonal deletion: apoptosis
or
receptor editing: further light chain gene arrangements of variable regions

Question 21

what are anergic B cells

Answer 21

B cells that bind to soluble self antigens (not on cell surface)
and the B cell down regulates its level of BCR so can escape the bone marrow
cells become unresponsive

Question 22

common lymphoid progenitor goes into thymus and gets a signal to start doing what

Answer 22

rearranging their t cell receptor genes

Question 23

T cells expressing TCR must bind with what to be positively selected

Answer 23

self MHC

Question 24

what protein signals to initiate T cell receptor rearrangements

Answer 24

notch

Question 25

if TCR recognises MHC it is

Answer 25

positively selected

Question 26

if TCR recognises MHC too well it is

Answer 26

negatively selected

Question 27

what are examples of the T cell markers

Answer 27

CD3 CD4 CD8

Question 28

what are the types of cells in the thymus

Answer 28

lymphoid cells
epithelial cells
macrophages and dendritic cells

Question 29

which part of the thymus are the t cells positively selected

Answer 29

the cortex

Question 30

they then move into the

Answer 30

medulla

Question 31

before t cells come out the thymus that have both ___ and ___ on the surface

Answer 31

CD4 and CD8

Question 32

what is expressed on all T cells

Answer 32

CD3

Question 33

where does the CD3 transmits signal to after TCR recognition

Answer 33

the nucleus

Question 34

γδ T cells dont express what

Answer 34

CD4 or CD8

Question 35

where are the majority of the γδ T cells located

Answer 35

skin or gut

Question 36

when the cell goes into the thymus it doesnt have

Answer 36

CD3 CD4 or CD8 (double negative)

Question 37

if the γδ genes are rearranged it leaves the thymus very quickly and it has which marker

Answer 37

CD3

Question 38

if αβ genes are rearranged the cells express CD4 and CD8 making them

Answer 38

double positive

Question 39

the under goes positive selection: cells die if they

Answer 39

dont bind to self MHC

Question 40

cells survive positive selection if they

Answer 40

do binds to self MHC

Question 41

they then undergo negative selection:
cells survive id the bind to self MHC

Answer 41

moderately

Question 42

cells die in negative selection if the bind to self MHC

Answer 42

tightly

Question 43

if they survive they turn off

Answer 43

either CD4 or CD8 and leave the thymus and go into the blood

Question 44

where does positive selection take place

Answer 44

cortex

Question 45

where does negative selection take place

Answer 45

medulla