B cell development 1 Flashcards
Where do B cells develop?
Bone marrow
Where do B cells go after developing in the bone marrow?
Secondary lymphoid tissues
What is tolerance?
Removing self reactive B and T cells
What are secondary lymphoid tissue exmpes?
Lymph nodes, spleen, blood, lymph, peyers patches
Where may B cells encounter an antigen and thus get activated?
Secondary lymphoid tissues
What do pro-b cells develop from?
Hematopoietic stem cells
What cells can be formed from myeloid progenitors?
Neutrophils, macrophages, eosinophils, RBCs,
What cells can be formed from lymphoid progenitors?
T cells, B cells, NK cells
What are CDs?
Surface proteins–> cluster of differentiation
What is an indicator of a cell differentiating into a B cell?
CD127 (a component of the IL7 receptor)
How is B cell development direted?
Integrins on the B cell interact with molecules on the surface of the bone marrow
How is a B cell directed to become a B cell?
Interaction w/ bone marrow stromal cell that gives the signal for IL7 to be produced. IL7 then directs the b cell
What configuration are heavy and light chain genes in in stem cells?
Germline
What configuration are the heavy chain and light chain genes in early pro b cells?
Heavy chain = D-J rearrangement
Light chain = germline
Where does D-J rearrangement occur?
Both chromosomes
What configuration are the heavy chain and light chain genes in late pro b cells?
Heavy chain = V-DJ rearrangement
Light chain = germline
Where does V-DJ rearrangement occur?
Only one chromosome
What configuration are the heavy chain and light chain genes in large pre b cells?
Heavy VDJ are rearranged
light chain is germline
When in B cell development do light chain genes rearrange?
Small pre-b cell
When in B cell development is the heavy chain gene transcribed into mRNA?
Large pre-B cell
Where is the heavy chain stored after it is made, and before it has associated with a light chain?
The endoplasmic reticulum
What configuration are the light chain genes in in the small pre-b cell?
V and J are rearranging
What is a pre-b receptor
An IGM heavy chain associated with surrogate light chain polypeptides
Which cells express a pre-b receptor?
pre-b cells
What does expression of a pre-b cell receptor signal the cell to do?
Divide and replicate
WHen is the proliferation step in the stages of b cell development in the bone marrow?
Before the small pre-b cell is achieved and after the large pre-b cell
Once the B cell has been stimulated to divide by the pre b cell, what do they do?
They independently rearrange their light chain genes
When rearranging genes, what is the proportion of cells that are going to be productive?
just under 2/3–> 2/3 will cause a frame shift and some of the 1/3 will be stop codons
then repeat f the 2nd chromosome if it doesn’t work on the first
How many light chain loci are there in a cell?
4–> one kappa and one lambda, then double bc one chromosome from mother and one from the father
How many chances do you have to productively rearrange the light chain loci?
4
Which light chain genes are attempted to be rearranged first?
Kappa
What happens if none of the light chain rearrangements are successful?
Cell will die by apoptosis
