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Flashcards

Antibodies

hazel wilkie Physiology Inglês 56 flashcards

Flashcards do conjunto (56)

  1. 1what cells produce antibodies?B cells
  2. 2where do lymphocytes arise from?- stem cells in the bone marrow
  3. 3where do lymphocytes differentiate?central lymphoid organs
  4. 4where do B cells differentiate?bone marrow
  5. 5where do t cells differentiate?the thymus
  6. 6what are naive b cells?ones that have not met an antigen
  7. 7where do naive b cells circulate from and into?they circulate from blood into peripheral lymphoid tissues
    • Peripheral lymphoid tissues are the main site of antigen encounter
  8. 8where do lymphocytes migrate to?bloodstream to peripheral secondary lymphoid organs - lymph nodes, spleen, gut-associated lymphoid tissue (GALT), Peyers patches, tonsils, appendix.
  9. 9how do recirculating b cells enter back into the bloodstream?the thoracic duct
  10. 10how are lymph nodes organised?- into a cortex and inner medulla
  11. 11what does the cortex consist of?- Cortex has an outer section of B cells organised into follicles,
    -and a paracortical area of T cells and dendritic cells (blue).
    - Germinal Centres of B cell proliferation form during an immune response.
  12. 12what does the medulla consist of?Medulla consists of macrophages and antibody secreting B cells (Plasma cells). Antigen (in DC) enter through afferent lymphatics.
  13. 13what is the role of the red and white pulp in the spleen?- site of RBC destruction
    - white - lymphoid
  14. 14how does blood carrying lymphocytes and antigens enter the spleen?enter from a trabecular artery into a central arteriole.
    They can then pass into a marginal sinus and exit through a trabecular vein.
  15. 15do antigens enter the spleen via the blood or the lymph?BLOOD
  16. 16describe the white pulpThe marginal sinus is surrounded by lymphocytes, and within it is the periarteriolar sheath (PALS), made up of T cells. B cell follicles and a B cell corona also form
  17. 17what are the key features of the adaptive immune response?- antigen specificity and memory
  18. 18describe the course of antibody production upon meeting an antigen- the secondary (memory) response is faster,
    - can produce more antibody,
    - and does not prevent you from making a response to another antigen (multiple antigens -vaccination)
  19. 19what are the two ways antibodies can be expressed?- membrane bound (B cell receptor)
    - secreted forms
  20. 20do B cells express multiple Ab specificity?no - single specificity only
  21. 21what are the 2 functions of Abs?firstly to bind the pathogen that elicited its production,
    - and secondly to recruit other cells and molecules that will lead to clearance or destruction of the pathogen.
  22. 22describe the structure of AbsAb are made of four polypeptide chains, two identical heavy (H) chains and two identical light chains (L).
  23. 23how about the heavy chains bonded together?The H chains are disulfide bonded to each other, and each H chain is also disulfide bonded to a L chain.
  24. 24what light chains exist?lamba and kappa
    - Any individual Ab has either one or the other, never a mixture of each.
    In human the ratio is 2:1 in favour of kappa
  25. 25what do two identical H and L chains result in?2 identical bonding sites
  26. 26which region binds with the antigen?Fab
  27. 27which region binds with receptors?Fc
  28. 28what are the 3 globular domains of an Ab?(V region)
    - variable light
    - variable heavy
    - constant heavy
    -constant light
  29. 29what is produced from the proteolytic cleavage by papain?2 Fab regions and 1 Fc
  30. 30what is produced from the proteolytic cleavage by pepsin?1 Fab + many Fc
  31. 31what is the final antigen specificity determined by?a combination of loops from H and L chains, and not either alone.
  32. 32what are the ways in which antigens can bind to antibodies?Antigens can bind in pockets or grooves, or on extended surfaces
  33. 33what is the antibody repertoire?The total number of antibody specificities available in an individual
    The number of antibody specificities available at any one time is, however, limited to the total number of B cells present.
  34. 34what did the gremlin theory suggest?Germline Theory suggested that a separate gene existed for each Ab. Not really the case.
  35. 35what is the Somatic Diversification theory?proposed that repertoire is generated from a limited number of V region genes that undergo alteration. Essentially correct.
  36. 36how is the sequence of a V region generated?y the somatic recombination of separate gene segments - Chromosomal Rearrangement
  37. 37what are v region genes constructed from?multiple gene segments
  38. 38where is extra variability created from?junctional diversity
  39. 39summarise the ways in which Ab diversity is created1 -rearranging multiple gene segments
    • 2 - junctional diversity
    • 3 - different combinations of H and L chains
    • All the above happen during B cell development, long before it ever sees antigen
    • But there is also
    4 - Somatic Hypermutation which occurs after B cells have become antigen activated in the lymph node.
  40. 40describe somatic hypermutationDuring the course of an immune response mutations accumulate in the V regions of the H and L chain genes.
    Some of these will bind antigen better and these cells are selected to expand and secrete antibody. This is called affinity maturation.
  41. 41what are the five classes of Ab?defined by heavy chain
    IgG,M,D,A,E
  42. 42what antibody do all b cells initially express a membrane form of ?IgM
    After antigen stimulation they can secrete a soluble version of the same IgM made by alternative mRNA processing.
  43. 43what is iso type switching?where the IgM Heavy chain is swapped for IgG etc. This supplies functional diversity.
  44. 44what antibody multimers exist?ism as a pentamer
    IgA as a dimer
    both involve an additional J chain
  45. 45what antibodies predominate in plasma?IgG and IgM
  46. 46what are the main main isotypes in extracellular fluid?IgG and monomeric IgA
  47. 47what antibody predominates in secretions across epithelia, including breast milk?dimeric IgA
  48. 48what antibody does the foetus receive by the placenta?IgG
  49. 49where is IgE found?IgE is found mostly near to epithelial Surfaces, especially gut, lungs and skin.
  50. 50what cells take up antigen-antibody complexes?phagocytes
  51. 51what are high levels of Ab-Ag complexes prevalent in?some autoimmune disease, major cause of glomerulonephritis
  52. 52when are there small immune complexes formed ?early in the response
    the small immune complexes don not fix complement and are not cleared from circulation
  53. 53at what point are immune complexes formed that can fix complement and are cleared from the circulation?at intermediate stages
  54. 54when are immune complexes of intermediate size?late in the response when there are large amounts of antibody and little antigen
  55. 55what are monoclonal antibodies?antibodies that are made by identical immune cells that are all clones of a unique parent cell
    Monoclonal antibodies can have monovalent affinity, in that they bind to the same epitope (the part of an antigen that is recognized by the antibody)
    A monoclonal antibody is made so that it binds to only one substance
  56. 56how do you make monoclonal antibodies?1. B cells from mouse immunised with antigen + myeloma cells
    2. fuse cells
    3. grow in drug - containing medium
    = only hybrid cells survive
    4. select for antigen-specific hybridoma
    5. clone selected hybridoma cells

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Physiology (Cells) FlashCards sobre Antibodies, criado por hazel wilkie em 01-05-2017.
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hazel wilkie
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