Microbiology Chapter 15

  1. What does the adaptive immune response do?
    develops the most effective means to eliminate a specific invader
  2. How long does it take the adaptive immune system to build an effective response?
    a week or more
  3. Name the three characteristics of the adaptive immune sstem
    • it has memory and a stronger response is created to re-exposure of the same pathogen
    • The response has a molecular specificity
    • distinguishes between healthy self cells and dangerous cells
  4. What comprises the lymphocytes?
    • B Cells
    • T Cells
  5. What is the primary response?
    the first response to an antigen
  6. What is the secondary response?
    The second response to an antigen which the immune system remembers
  7. What is humoral immunity?
    works to eliminate extracellular antigens and depends on B Lymphocytes
  8. What is cell-mediated immunity?
    Deals with antigens within a host cell and depends on T Lymphocytes
  9. Where do B cell develop and mature?
    Bone Marrow, or Bursa
  10. The presence of extracellular antigens cause B cells to...
    proliferate and differentiate into plasma cells and memory B cells
  11. What do Plasma cells produce?
    Y-shaped proteins, Antibodies
  12. What are the two ways an antibody protects the host?
    • directly
    • indirectly
  13. How does an antibody protect the host directly?
    by binding to an antigen and coating it's receptors so the antigen cannot bind to a host cell
  14. How does an antibody protect the host indirectly?
    by "tagging" an antigen so the immune system knows to eliminate it
  15. What are the receptors on B cells called?
    B-Cell receptor (BCR)
  16. What cells assist B cells to become activated?
    helper T cells
  17. What lymphocytes are used in cell-mediated immunity?
    T lymphocytes
  18. Where do T cells mature?
  19. What are the 3 subsets of T cells?
    • cytotoxic T Cells
    • helper T Cells
    • regulatory T Cells
  20. What do BCRs recognize?
    free antigens
  21. What do TCRs recognize?
    an antigen presented by the body's own cell
  22. What is a TCR?
    T-Cell receptor
  23. What to regulatory T cells do?
    prevent the immune system from making a response against "self" molecules and cells
  24. What do T cells differentiate and proliferate into?
    • Effector T Cells
    • Memory T Cells
  25. What do effector cytotoxic T cells do?
    respond to intracellular antigens and induce apoptosis in infected cells
  26. What do effector helper T cells do?
    • coordinate humoral and cell-mediated immunity
    • active B cells and macrophages
    • produce cytokines to direct and support other T cells
  27. What is the lymphatic system?
    a collection of tissues and organs that brings populations of B cells and T cells into contact with antigens
  28. What does lymph contain?
    white blood cells and antigens from the tissues
  29. What is a secondary lymphoid organ?
    sites where lymphocytes gather to contact antigens
  30. What are the secondary lymphoid organs
    lymph nodes, spleen, tonsils, adenoids, appendix
  31. Where are Peyer's Patches located?
    intestinal wall
  32. What are the primary lymphoid organs?
    Bone Marrow and Thymus
  33. What occurs after lymphocytes mature?
    they gather in secondary lymphoid organs and wait to come into contact with an antigen
  34. Where does the word "antigen" come from?
    antibody generator
  35. What is an immunogen?
    an antigen that elicits an immune response
  36. What are the two main categories of antigens?
    • T-dependent antigens
    • T-independent antigens
  37. What are T-dependent antigens?
    the responding B cell requires confirmation from Th cell to be activated
  38. What are T-independent antigens?
    • activated B cells without Th cell help
    • include LPS
  39. What are epitopes or antigenic determinants?
    specific regions of an antigen that the immune system recognizes
  40. What are the two parts of an antibodies/immunoglobulin?
    • Y Shape
    • two arms (Fab region) bind antigen
    • Stem (Fc region)
  41. What are the 2 chains within an antibody?
    • heavy chain-more amino acids
    • light chain-less amino acids 
    • held together by disulfide bonds
  42. What is the end of the Fab region called?
    The Variable Region
  43. What does the variable region have?
    the antigen binding side where specific epitope binds
  44. Where is the constant region of an antibody?
    The lower part of the arms and the stem
  45. Why is it called the "constant region"?
    Because it is identical among Immunoglobulin classes
  46. What is neutralization?
    prevents toxins and viruses from binding to host cell
  47. What is opsonization?
    enhancement of phagocytosis
  48. What is Complement system activation?
    leads to inflammation, opsonization and MAC (Membrane attack complexes) formation
  49. What is immobilization and prevention of adherence?
    binding to bacterial flagella or pili interferes with attachment to host
  50. What is Cross-linking?
    Two arms of antigen bind to separate antigens, clumping them together and making phagocytosis more efficient
  51. What is Antibody-Dependent cellular toxicity
    targets infected host cell for destruction by Natural Killer cells
  52. What are the 5 immunoglobulins?
    • IgM
    • IgG
    • IgA
    • IgD
    • IgE
  53. Describe immunoglobulins
    Each class has the same constant region, and has distinct functions and properties
  54. What is % of IgM circulating?
  55. Describe IgM
    First antibody class produced druing the primar yresponse
  56. Describe IgM strucutre
    • pentamer-5 monomeric subunits joined together, meaning there are 10 antigen binding sites
    • Its large size keeps it in the blood stream
  57. When is IgM start being produced?
    at Birth
  58. What is the % of IgG circulating?
    80-85% of total serum (liquid portion of blood)
  59. When is IgG produced during infection?
    first and most abundant circuating class produced during secondary immune response
  60. When is IgG first produced?
    • transported across placenta 
    • IgG is found in colostrum and is absorbed by newborn's intestinal tract
  61. What % of IgA is circulating?
  62. What form is IgA in?
    Monomeric, most however is a dimer
  63. Where is IgA found?
    secreted form is important in mucosal immunity and is found in gastrointestinal, genitourinary, respiratory tracts
  64. Where is IgA produced?
    by plasma cells of MALT
  65. How much IgD is circulating?
  66. What is the purpose of IgD?
    involved with development and maturation of antibody response, but its function in blood is not clearly defined
  67. What amount of IgE is found in blood?
    the amount is barely detectable in normal blood
  68. Where is IgE found?
    bound to Fc region of Mast and Basophils
  69. What is IgE associated with?
    • allergies
    • when IgE binds to normally harmless particles it causes an allergic reaction
  70. What is selection of B cells?
    only B cells that recognize their specific epitope respond to the antigen and become activated
  71. What do plasma cells produce?
  72. What is clonal selection?
    When activated B cells undergo mitosis to create a large number of identical B cells all creating the same antibody
  73. What do Th cells secrete?
    cytokines that help with activation of B cells and Macrophages
  74. What do Tc cells secrete?
    "death packages" that lead to apoptosis of infected cells
  75. In the case of B cells, what do clonal selection lead to?
    formation of plasma cells and memory B cells
  76. In the case of T cells, what does clonal selection lead to?
    • effector T cells (Th and Tc)
    • Memory T cells
  77. What is an immature lymphocyte?
    lacks fully developed antigen-specific receptors
  78. What is a Naive Lymphocyte
    Has receptors, but has never encountered its antigen
  79. What is an activated lymphocyte?
    bound to antigen and able to proliferate into plasma cells
  80. What is an effector lymphocyte?
    • descendants of activate lymphocytes
    • plasma cells, Tc Cells, Th Cells
  81. What is a Memory Lymphocyte?
    long-lived descendants of activated lymphocytes--responsible for secondary response
  82. how long does the primary response take to be effective?
    10-14 days
  83. What occurs during the primary response?
    • B cells are activated and differentiate into plasma cells
    • plasma cells generate antibodies and then undergo apoptosis after a few days
    • B cells continue to make plasma cells in presence of antigen
  84. What is affinity maturation?
    B Cells that bind to antigen longest are most likely to proliferate
  85. What do all plasma cells initially secrete?
  86. What is Class Switching?
    most plasma cells initially secrete IgM, however Th can induce some activated B cells to become plasma cells that secrete other antibody classes (IgG)
  87. What occurs during T-Independent response?
    Molecules with many identical evenly spaced epitopes (LPS) can activate B cells directly
  88. Why are T-Independent responses medically important?
    Because children are not good at mounting a response against these types of antigens
  89. What does MHC stand for?
    Major Histocompatibility Complex
  90. What is an MHC?
    molecules on surface of B cells used to present antigens to T cells
  91. What is the difference between TCR and BCR?
    • TCR only interacts with antigens presented on MHCs
    • BCR interacts with free antigens
  92. What do MHC Class 1 present?
    endogenous antigens
  93. What do MHC Class 2 present?
    • exogenous antigens
    • ex LPS
  94. Which T cell recognizes MHC Class 1
    Cytotoxic T Cells
  95. Which T Cel recognizes MHC Class 2?
    Helper T cells
  96. What is an antigen presenting cell example?
  97. What protein does Th cells have?
    CD4 Proteins
  98. What protein does Tc cells have?
    CD8 Proteins
  99. How do Dendritic cells alert T cells to a pathogen?
    costimulatory molecules
  100. in what cells does Tc cell induce apoptosis?
    infected "self" cells and cancer cells
  101. What does the Tc cell produce to induce apoptosis?
    proteases and cytotoxins
  102. What do NK cells induce?
  103. What is the process in which NK cells recognize infected host cells?
    Antibody-dependent cellular cytotoxicity
  104. What is positive selection in T cells
    They are destroyed if they cannot recognize MHC complex
  105. What is negative selection in T cells?
    a T cell is eliminated if it recognizes "self" peptides presented on MHC molecule
  106. What is negative selection in B cells
    Induces apoptosis if they incorrectly identify "self" cells as foreign
Card Set
Microbiology Chapter 15
Microbiology Chapter 15