1. The immune system evolved for what purpose?
    To isolate/eliminate pathogens
  2. What 2 problems can occur with the immune system?

  3. What is hypersensitivity?
    An immune response to an environmental agent (allergen)
  4. Hypersensitivity = ?
  5. What are the 4 types of hypersensitivity?
    Type I: immediate or anaphylactic

    Type II: antibody-dependent cytotoxic

    Type III: immune-complex

    Type IV: delayed or cell-mediated
  6. What is Type I hypersensitivity?
    Immediate-type or anaphylactic hypersensitivity:

    Fast! Occurs 5-30 minutes after exposure
  7. Give examples of Type I hypersensitivity.
    Immediate-type or anaphylactic hypersensitivity:

    inhaled: hay fever, pet dander, mold spores, dust mites

    injected: bee sting allergies, vaccines, drugs

    ingested: food, orally administered drugs (penicillin)
  8. Describe the step-by-step process of Type I hypersensitivity.
    Anaphylactic reactions:

    1. initial allergen exposure induces IgE production

    2. IgE "sensitizes" mast cell by attaching its FC region (leg of Ab) to mast cell surface receptor (IgE normally is not on mast cells.

    3. subsequent allergen exposure

    4. Fc receptors cross linked

    5. degranulaltion of histamine and/or leukotriens (highly inflammatory)
  9. What is Type II hypersensitivity?
    Antibody-dependent cytotoxic hypersensitivity:

    Ab combines with host cell--death by complement activation or phagocytosis
  10. Give examples of Type II hypersensitivity.
    Antibody-dependent cytotoxic hypersensitivity:

    blood group incompatibility

    Rh factors in pregnancy
  11. AB - universal recipient

    O - universal donor

    Rh+ can accept + or -

    Rh- can only accept -

    Ab can cross placenta
  12. What is Type III hypersensitivity?
    Immune-complex hypersensitivity:

    Small particulate Ab-Ag combination (called immune complex)

    • This complex can stimulate the rest of the immune system
    • -results in surrounding host cell/tissue destruction
    • -serum sickness

    • example:
    • -Snake venom
  13. What is Type IV hypersensitivity?
    Delayed or Cell-mediated hypersensitivity:

    Occurs ~24-72 hours after Ag exposure

    • example:
    • -TB skin test
    • -Poison ivy
  14. What is Autoimmunity?
    An immune response to self proteins

    • Immune cells that attack the host (self) are removed during fetal development
    • -called clonal deletion

    Autoimmunity is loss of self tolerance
  15. Types of Autoimmune Diseases:
    Cytotoxic autoimmune reactions

    Immune complex autoimmune reactions

    Cell-mediated autoimmune reactions
  16. An Autoimmune disease--Cytotoxic autoimmune reactions
    Antibodies react to cell-surface Ag

    No cytotoxic destruction of host cells

    • examples:
    • -Myasthenia gravis (muscle weakness)--make Ab against Ach receptors and the receptors get destroyed
    • -Graves' disease (overactive thyroid)
  17. An Autoimmune disease--Immune complex autoimmune reactions
    Immune complexes are deposited on host cells

    • examples:
    • -Systemic lupus erythematosus--autoimmune response is directed at autoantigens present in almost all host cells. Inflammatory reaction = cell/tissue destruction. Trigger factors remain unknown
    • -Rheumatoid arthritis--joint infiltration with immune cells. Eventually, immune cells release proteinases and collagenases that damage cartilage, ligaments, and tendons.
  18. An Autoimmune disease--Cell-mediated autoimmune reactions
    Mediated by T cells (no antibodies)

    • examples:
    • -Multiple sclerosis--immune response to myelin basic protein. Infiltration of immune cells in CNS. Create T cells that attack myelin sheath.
    • -Insulin-dependent diabetes mellitus--selective destruction of insulin producing cells in the pancreas. AKA type I diabetes (juvenile-onset). Attacks insulin-making cells--> B cells.
Card Set
Immune system