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25 Cards in this Set
- Front
- Back
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What are B cells derived from?
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Hematopoietic stem cells
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What is the primary lymphoid organ for B cell differentiation?
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Bone marrow
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Which cytokine interacts with stromal cells of the bone marrow to enhance B cell proliferation?
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IL-7
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Stem cell factor (SCF) interacts with what on the B cell to promote proliferation?
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Kit
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What is the earliest distinguishable cell in B lineage called?
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Pro-B cell
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What rearrangement occurs in an early pro-B cell?
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D-J rearrangement
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What rearrangement occurs in a late pro-B cell?
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V-DJ rearrangement.
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About what percent of pre-B cells undergo successful rearrangement?
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50%
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Pre-B cell receptor is composed of what?
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Surrogate light chain paired with rearranged heavy chain.
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What causes surface Ig in B cells to have only one specificity?
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Allelic exclusion
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Which genes rearrange first on the light chain of a b cell?
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k chain genes
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What happens if neither of the chromosomes coding for k chains successfully rearranges?
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lambda gene rearrangements take place.
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What happens if lambda rearrangement is not successful?
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The cell dies
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Where are B-1 cells predominantly located?
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Peritoneal and pleural cavities
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Which type of Ig is predominantly secreted by B-1 cells?
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IgM
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B-1 B cells mainly produce antibodies against what?
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Bacterial polysaccharides
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What happens to an immature B cell that reacts with self antigen?
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It is retained in the bone marrow
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What happens to an immature B cell that does not react with self antigen?
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It moves to the blood where it expresses IgD and IgM.
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What is receptor editing?
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A process that can rescue a self-reactive b cell by inducing rearrangement of light chain genes.
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What happens if receptor editing is not successful?
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Once all possible light chain rearrangements have been exhausted the auto-reactive B cell will be removed.
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What are the three fates for a B cell that reacts with self antigen?
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Death, receptor editing, and anergy.
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What is central tolerance?
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The process by which self-reactive B cells are removed and inactivated within the bone marrow.
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What is peripheral tolerance?
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The deletion or inactivation of immature B cells in the blood and peripheral tissues.
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What happens if an immature B cell fails to gain access to a primary lymphoid follicle?
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It will die
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What processes occur in the germinal centers?
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Isotype switching and somatic hypermutation
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