The development of B lymphocytes Flashcards
B cell lineage
pluripotent hematopoietic stem cell -> common lymphoid progenitor -> B-cell precursor -> pro-B cell
what stage does a immunoglobulin start being made in the bone marrow
during large pre-B cell a mew heavy chain is made
what stage in the bone marrow does the heavy chain genes start forming
early pro-B
during which stage in b-cell development is the light chain genes develop
in small pre-b cell
does the B cell need to remain in contact with the bone marrow while it develops
Yes
what % of late pro-b cells die by apoptosis during H chain gene rearrangement
50%
which receptor monitors the quality of immunoglobulin heavy chains
pre-B cell receptor
which receptor causes allelic exclusion at the immunoglobulin heavy chain locus
pre-B cells
what happens during allelic exclusion on the immunoglobulin heavy-chain locus
- RAG gene expression stops
- RAG proteins degraded
- other DNA locus is reorganized to prevent rearrangement
when does rearrangement of the light chain loci occur
in pre-B cells
do B cell tumours carry chromosomal translocations in order to join immunoglobulin genes with genes that regulate cell growth
yes
what cells scan in the bone marrow for self-reactive B cells
stromal cells and blood cells
what is the term for antigen receptors of autoreactive immature B cells that can be modified by a certain cell
receptor editing
what happens if editing does not occur in the immature B cells
clonal deletion
what is the term for a cell becoming unresponsive, so cells will still bind but will not activate any cascades
anergic
what are the 3 options a immature B cell could go through before they leave the bone marrow
- survive through receptor editing
- die by apoptosis
- become anergic
what is CCL21 secreted by
stromal cells of lymph node and dendritic cells
what is CCL19 secreted by
dendritic cells
what is CXCL13 secreted by
follicular dendritic cells
what is the use of follicular dendritic cells
provides the final signal needed by B cells to mature
where do mature B cells need to pass through in order to survive
secondary organs
what do mature B cells do when they leave the bone marrow
search for antigen and recirculate if they did not find any as naive B cells
what does an encounter with antigen lead to for B cells with the help of CD4
turns the activated B cells into plasma cells and memory B cells
do memory B cells require persistent follicular stimulation to survive?
no
do memory B cells get activated quicker during a secondary exposure
yes
do B cell tumours reflect the B cells at different stages of development
yes
