Step 1 Immunology

  1. Th1 cells make ____ to activate ___
    • IL-2 and IFN-gamma
    • macrophages and CD8 T cells
  2. Th1 cells are inhibited by this
  3. Th2 cells make hese
    IL-4, 5, 10
  4. Th2 cells are inhibited by this
  5. Where is the antigen loaded for MHC I?
    In the RER of mostly intracellular peptides
  6. Which MHC uses Ag loading involving release of invarient chain, and where does this occur
    • MHC II
    • In an acidified endosome
  7. Structure of MHC II molecules
    • alpha and beta chains
    • symetrical
    • peptide-binding groove between the two
  8. Structure of MHC I molecules
    • alpha clover leaf
    • beta-2 microglobulin
    • Peptide-binding groove is in alpha clover
  9. Hemochromatosis HLA
  10. Psoriasis, IBD, Reiter's syndrome HLA
  11. Graves' disease HLA
  12. MS, hay fever, SLE, Goodpasture's HLA
  13. DM I HLA
  14. RA, DM I HLA
  15. Pernicious anemia and Hashimoto's HLA
  16. Steroid-responsive nephrotic syndrome HLA
  17. NK cells use these to kill cells
    perforin and granzymes
  18. These enhance NK cell activity
    IL-12, IFN-B, IFN-a
  19. Macrophage-lymphocyte interaction
    • Lymphocytes release IFN-gamma
    • Macrophages release IL-1 and TNF-a
    • They stimulate each other this way
  20. Action of superantigens
    • Cross-link B-region of TCR to the MHC class II on APCs
    • IFN-g released from Th1 cells
    • IL-1 IL-6 and TNF-a released from macrophages
  21. Effect of endotoxins/LPS
    • Directly stimulate macrophages by binding to endotoxin receptor CD14
    • Th cells are NOT involved
  22. Th activation costimulator signal
    Interaction of B7 and CD28
  23. CD8 T cell activation following MHC I recognition
    IL-2 from Th cell activation CD8 to kill
  24. B-cell class switching: 2 steps
    • IL-4, 5, or 6 from Th2 cell
    • CD40 receptor activation by binding CD40L on Th cell
  25. Igs allowing complement binding
    IgG and IgM
  26. IL-1 secreted by
  27. IL-1 activity
    • Pyrogen, lethargy, anorexia, inflammation
    • Induces chemokine production to recruit leukocytes
  28. IL-2 secreted by ___ and stimulates ___
    • Th cells
    • Helper and cytotoxic T cells
  29. IL-3 source and function
    • Activated T cells
    • Like GM-CSF, supports bone marrow growth
  30. IL-4 source and function
    • Th2 cells
    • Class switching to IgE and IgG
  31. IL-5 source and function
    • Th2 cells
    • Class switching to IgA
    • Production and activation of eos
  32. IL-6 source
    Th cells and macrophages
  33. IL-6 function
    Proudction of acute-phase reactants and Igs
  34. IL-8 source and function
    • macrophages
    • recruit PMNs
  35. IL-10 source and fxn
    • Tregs
    • Inhibits Th1, activates Th2
  36. IL-12 source and function
    • B cells and macrophages
    • Activates NK and Th1 cells
  37. IFN-g source and function
    • Th1 cells
    • Stimulates macrophages
    • Activates Th1, inhibits Th2 (opposite IL-10)
  38. TNF source and function
    • Macrophages
    • Mediates septic shock
    • Leukocyte recruitment, vascular leak
    • Cachexia
  39. IFN-a function
  40. B cell surface proteins
    • IgM
    • CD 19, 20, 21 (EBV), 40
    • MHC II
    • B7
  41. Macrophage cell surface proteins
    • MHC II
    • B7
    • CD 40, 14
    • Fc and C3b receptors
  42. NK cell CDs
    CD16, CD56
  43. Anti-inflammatory
    • TGF-B (induces apoptosis, inhibits Th2)
    • IL-10
  44. C1 esterase inhibitor deficiency
    Hereditary angioedema
  45. C3 deficiency
    • Severe recurrent pyogenic sinus and respiratory tract infections
    • Type III hypersensitivity susceptibility
  46. DAF deficiency
    Complement-mediated lysis of RBCs and PNH
  47. IFNs induce this
    Ribonuclease production for viral protein synthesis inhibition
  48. Passive immunization following exposure to these
    Tetanus, Botulinum, HBV, Rabies
  49. What is anergy?
    When self-reactive T cells become nonreactive due to lack of costimulatory molecule
  50. Defect in Bruton Tyrosine Kinase
    • Bruton's agammaglobulinemia
    • Blocks B-cell differentiation
    • Recurrent bacterial infections
    • Decreased B cells and Igs of all classes
  51. Defective CD40L on helper T cells
    • Inability to class switch --> Hyper-IgM syndrome
    • Severe pyogenic infections early in life
    • Lots of IgM, little of the rest
  52. IgA deficiency
    • Sinus and lung infections
    • Milk allergies, etc
    • Anaphylaxis on exposure to blood products
  53. Normal number of B cells with decreased plasma cells and Ig
    • Common variable immunodeficiency
    • Defect in B cell maturation
    • Can be acquired in 20s-30s
    • Risk of autoimmune, lymphoma, sinopulmonary infections
  54. Disseminated mycobacterial infections
    • IL-12 receptor deficiency
    • Low Th1 response, low IFN-g
  55. Hyper-IgE syndrome (Job's)
    • Failure to produce IFN-gamma --> nonresponsive PMNs
    • Coarse facies, cold staph abscesses, retained teeth, derm problems
  56. Ataxia-telangiectasia triad
    Ataxia, spider angiomas, IgA deficiency
  57. Wiskott-Aldrich syndrome
    • Deletion of B and T cells, XLR
    • Thrombocytopenic purpura, Infections, Eczema
    • IgM will be low, high IgE and IgA
  58. Recurrent bacterial infections without pus, delayed umbilicus separation
    • LAD
    • Defect in LFA-1 integrin (CD18) protein on phagocytes
    • Labs show neutrophilia
  59. Chediak-Higashi syndrome defect and symptoms
    • AR defect in microtubules
    • Staph and strep pyogenic infections, partial albinism, peripheral neuropathy
  60. Negative nitroblue tetrazolium dye reduction test
    • CGD
    • Lack of NADPH oxidase causing decreased ROS and absent PMN respiratory burst
  61. Susceptibility in CGD
    • Catalase-positive organisms:
    • s. aureus
    • e.coli
    • pseudomonas capecia
    • serratia
    • nocardia
    • aspergillus
Card Set
Step 1 Immunology
USMLE step 1 immunology