B cell differentiation

  1. early Pro-B
    rearrangement of D-J of heavy chain
  2. later Pro-B
    rearrangement of V-DJ of heavy chain
  3. large Pre-B cell
    small amts of expression of heavy chain on outside of receptor; expression signals termination of heavy chain gene rearrangement
  4. Surrogate L chain
    made of VpreB and lambda 5 proteins; act as "L" chain so heavy chain can be expressed on outside of B cell in Pre-B cell stage

    its presence signals to stop H rearrangement and start L rearrangement
  5. mu Heavy chain
    its expression stimulates L chain rearrangement
  6. L chain rearrangement inhibitor
    causes VpreB and lambda 5 to be displaced and allows L and H chain to come together
  7. How does RAG play a role in B cell dev?
    it can phosphorylate to cause cessation of H chain gene rearrangement in pre-B cell stage

    turned on for L chain rearrangement
  8. When do L chains stop rearranging?
    one IgM is expressed on the surface of immature B cells
  9. What are three fates of immature B cells in bone marrow?
    • 1. strong signal binding with self-antigen=clonal deletion and apoptosis
    • 2. signal binding w/ sol self-antigen=immature B cell migrates to periphery and becomes inactive to Ag and eventually dies
    • 3. no signal binding w/ self-antigen=migrates to periphery and becomes mature B cell (expresses IgD and IgM)
  10. transitional B cells
    • immature B cells that leave bone marrow and enter periphery; can mature into 3 types of B cells:
    • 1. B-1 B cells
    • 2. marginal zone B cells
    • 3. follicular B cells
  11. B-1 B cells
    forms from transitional B cells; resides in pleural and peritoneal cavities and make natural Ab to function in innate immune response; esp useful against bacteria
  12. Marginal zone B cells
    live in marginal zone of spleen and make T-indep and T-dep Ab responses to bloodborne Ag
  13. Follicular B cells
    recirculate btw blood and lymphoid follicles and make T-cell dep and participate in germinal center rxn
  14. What are some characteristics of plasma cells?
    • no surface Ig
    • no MHC-2 expression
    • make secreted form of Ig
    • are not inducible (growth)
    • end stage of B cell differentiation
  15. What are some characteristics of a resting B cell?
    • isotype switch
    • hypermutations
    • expresses surface Ig
    • expresses surface MHC-2
    • does not secrete Ig
    • is inducible (growth)
  16. What are some characteristics of memory B cells?
    • can revert back to resting B cell stage
    • can express any Ig class
    • go to live in bone marrow and can stay for yrs
Card Set
B cell differentiation
MS1/Mod 1: immunology; B cell differentiation