immuno chapter 6.txt

  1. Repertoire assembly
    generation of diverse and clonally expressed B-cell receptors in the bone marrow
  2. Negative selection
    alteration, elimination, or inactivation of B-cell receptors that bind to components of the human body
  3. positive selection
    promotion of a fraction of immature B cells to become mature B cells in the secondary lymphoid tissues
  4. Searching for infection
    recirculation of mature B cells between lymph, blood, and secondary lymphoid tissues
  5. Finding infection
    Activation and clonal expansion of B cells by pathogen-derived antigens in secondary lymphoid tissues
  6. Attacking infection
    Differentiation to antibody-secreting plasma cells and memory B cells in secondary lymphoid tissue
  7. Primary Lymphoid tissue
    bone marrow
  8. Secondary lymphoid tissue
    lymph nodes, spleen, peyer's patches
  9. Path of B cells in lymph
    start in bone marrow and travel to secondary lymph (lymph nodes, spleen, peyer's patches)
  10. What cell markers does a HSC have?
  11. What is the first stage of a legit b cell?
    Pro- B cell
  12. Stem cell
    germline configuration
  13. Early pro B cell
    heavy chain rearrangement starts
  14. Late pro B cell
    heavy chain rearrangment continues
  15. Large pre B cell
    heavy chain is made
  16. Small pre b cell
    light chain rearrangement starts
  17. Imature B cell
    IgM on the surface
  18. stromal cells
    help the B cells differentiated by maintaing contact via adhesion molecules. They produce growth factors such as SCF which interacts with Kit receptor on B cells and IL-7 which helps development of the B cells
  19. Pro- B cell rearrangement
    has two chances to make a productive gene or apoptosis occurs
  20. Surrogate light chain
    fake light chain that acts as a place holder for the heavy chain during the Pre B cell stage
  21. Pre- BCR
    sLC and heavy chain. low amounts on the cell surface. binding a ligand means survival
  22. Allelic exclusion
    assembly of pre-bcr signals the cell to stop rearrangement of the other heavy chain gene
  23. Light chain rearrangment
    only one recombination event requires, but several attempts happen to make a correct gene
  24. First checkpoint
    late pro b cell stage- functional pre- BCR
  25. Second checkpoint
    small pre B cell - functional BCR
  26. What is rearrangment dependent on?
    RAG proteins
  27. Ig loci is...
  28. Ahammaglobulinemia
    x-linked disease blocking b cell developent at the pre-b cell stage so there is no circulating antibodies
  29. BTK
    signals b cell development
  30. What causes cancer
    high activity of recombination and mutations leads to an increase chance of mistakes
  31. Translocation
    different chromosomes fuse together
  32. B- 1 cells
    atypical subset of b cells that are made early in embryonic development. CD5 cell surface protein is a marker. antibodies are not diverse and tend to bind to many antigens
  33. B-1 cells in adult
    persist in the lymphoid tissue and can self renew
  34. Goal of selection
    eliminate potentially self reactive B cells
  35. How is selection done?
    b cells that bind to self antigen in the bone marrow and periphery will die or become in active.
  36. What happens when a b cell is self reactive?
    it is retained in the bone marrow and can change its BCR
  37. What leaves the bone marrow?
    immature B cell that is expressing IgM and IgD
  38. Receptor editing
    self reactive b cells reduce IgM and expression of rag proteins. Light chain is rearranged to make a new BCR
  39. What are the two outcomes of receptor editing?
    new BCR is not self reactive and will develop further; new BCR is self reactive and will continue rearranging until it runs out of attempts
  40. Clonal deletion
    self reactive b cells eventually die and are cleaned up by macrophages
  41. What happens when an immature B cell binds to monovalent or soluble self antigens?
    it becomes anergic and enters the periphery to die
  42. How do B cells enter the lymph node
    a homing mechanism using HEV; naive b cells bind to chemokines secreted by stomal cells.
  43. Where do B cells congrigate when they enter the lymph node
    lymphoid follicles
  44. Follicular dendritic cells (FDC
    secrete cytokines that stimulate survival and differentiation
  45. CXCL13
    survival signal
  46. BAFF
    differentiation signal; transforms immature B cells that enter follicle (d + m+++) to become mature b cells (d+++ m+)
  47. What happends to b cells that are anergic?
    they are stuck in the t cell area
  48. why is there a competition to enter the primary follicle?
    entry will increase life time of cell- majority dont enter
  49. What happens if antigen binding occurs?
    b cells recognizing are detained in the t cell area; cd4 t cells will help activate the b cells to plasma cells
  50. plasma cells
    very specialized; protein synthesis and secretion is highly developed and they lose MHC II and BCR expression
  51. Primary focus
    activated b cells
  52. germinal center
    formed by primary focus and migrates to primary follicle and then eventually becomes a secondary follicle
  53. Germinal center b cells
    differentiate and reside in the medullary cords, spleen, and bone marrow
  54. B cell cancer type
    is associates with the b cell stage of the tumor
  55. Acute lypboblastic leukemia
    tumor of the lymphoid protenitor located in bone and blood marrow; Ig V gene is unmutated
  56. Burkitt's lymphoma
    tumor of mature memory b cell which is in the periphery and has mutated Ig v genes, and intraclonal variability
  57. Multiple Myeloma
    tumor of plasma cell located in the bone marrow with mutated, no ig v genes, no variability within clone
Card Set
immuno chapter 6.txt
immuno chapter 6