Tusday 2 - Dirty D - B and T cell maturation

Question 1

BCR complex

Answer 1

Membrane-bound IgM + signaling chains CD79a&b

Question 2

how can you tell the difference between early pro-b cells and late pro-b cells depending on their markers

Answer 2

Early pro-B cells express TdT alone (but apparently they also express CD 34 in the figure he gave us)
Intermediate pro-B cells express both TdT and CD45R
Late pro-B cells express CD45R and have downregulated TdT

CD45R – (receptor for cell growth and differentiation) remains expressed on the surface throughout the remainder of B-cell ontogeny.

Question 3

CD34

Answer 3

adhesion factor that helps b cells bind to bone marrow stromal cells

only on the stem cells and early pro b cells

Question 4

difference between large pre-b- cells and small non-dividing pre-b- cells

Answer 4

large - have successfully rearranged their Ig heavy chain genes.

small - begin to rearrange their Ig light chain and upregulate RAG1,2

Question 5

IL-7

Answer 5

Pre-B cells express IL-7R and are stimulated to divide and differentiate using IL-7.

IL-7 is a hematopoietic growth factor secreted by bone marrow stromal cells. Helps drive the growth and differentiation of lymphoid progenitor cell lineages.

Question 6

VLA 4

Answer 6

As far as i can tell, same function as CD34.

adhesion factor that helps b cells bind to bone marrow stromal cells

only on the stem cells and early pro b cells

Question 7

c-KIT

Answer 7

on early and late pro b cells,

binds to stromal cells

allows for production of IL-7receptor

at this point VDJ recombination occurs

Question 8

what is the first point of b cell maturation that IgM (or BCR) appears on the surface

Answer 8

pre b cell

Question 9

what is the first point of b cell maturation that IgD appears on the surface

Answer 9

Naieve b cells

Question 10

XLA

Answer 10

x linked agammaglobulinemia

block at the pro-b cell to large pre-b cell transition

defect in Bruton’s tyrosine kinase (Btk), which is involved in signal transduction downstream of the pre-BCR

Question 11

three major populations of b cells in the periphery

Answer 11

follicular (b-2) - IgM, IgD, CD19,21,23

b-1 - IgM, CD5 - have the ability to replenish themselves

Marginal zone - IgM, CD1,19,21

Question 12

example of a TI-1 antigen

Answer 12

LPS, and other cell wall components, usually bind through TLR4 (nonspecific) or BCR (specific)

Question 13

example of a TI-2 antigen

Answer 13

LARGE POLYSACCHARIDE MOLECULES with repeating antigenic determinants

Question 14

what type of b cells can be activated without t help?

what do they produce?

Answer 14

B1

only IgM for TI1, mostly for TI2

Question 15

role of Th2 t cells on b cells

Answer 15

makes IL2,4,5, to push b cells in to proliveration and differentiation

Question 16

what is notch

Answer 16

something that thymic stromal cells made in order for t cells to develope

Question 17

CD25

Answer 17

Il-2- receptor

DN2 and 3 stages

Question 18

CD44

Answer 18

required for localization of bone marrow cells to the thymus

expressed in double negative 1 and 2 stages

Question 19

C-Kit

Answer 19

expressed on developing t cells from the stem cell all the way up to the double negative 2 stage

Question 20

Pre TCR

Answer 20

expressed at DN3,4

after which it becomes TCR in the double and single positive stages

Question 21

CD3

Answer 21

stage DN3 onward

Question 22

in what stage of development does the TCRbeta chain recombine

Answer 22

between DN2,3 (becomes pre t cell receptor)

Question 23

when does TCRalpha chain recombine

Answer 23

between DN4 and DP