1. The Immune System

2. Nonspecific Body Defenses Responds immediately Intact skin Mucous membranes Inflammatory Response Cellular Chemicals

3. Surface Protectors Skin, Mucous membranes Physical barrier Chemical barrier pH of skin; pH of vagina; sebum Stomach acid/enzymes Saliva/lacrimal fluids (lysozyme) Sticky mucus to trap invaders in digestive/respiratory passages

4. Cells and Chemicals Phagocytes Macrophages and Neutrophils Engulf foreign invaders Natural Killer Cells (NK) to “police” body Kill cancer cells, virus-infected cells NOT phagocytes (think chemical warfare)

5. Inflammatory Response Nonspecific response Cardinal Signs Redness Heat (inflamm… “set on fire”) Swelling Pain

6. Inflammatory Response Chemical “alarm” Damaged cells release histamine, kinins Causes blood vessels to dilate, leaky capillaries Activates pain receptors Attracts phagocytes (WBC’s) to injured area  Called Chemotaxis (cells follow chemical signal) Redness/heat from increased blood flow Also causes edema (swelling)

7. Inflammatory Response Prevents spread of damaging agents to other areas Disposes of cell debris and pathogens Begins repair process

8. Chemicals Complement Group of plasma proteins that circulate (inactive) Attach to foreign cells and puts holes in the cells  Foreign cells die Amplifies inflammatory response  Calls more phagocytes to area Cause CM’s of foreign cells to stick together

9. Chemicals Interferon Small proteins secreted by infected cells Attach to non-infected cells Slows down virus multiplication

10. Fever Abnormally high body temperature Pyrogens increase “thermostat” Chemicals secreted by WBC’s that have been exposed to foreign cells Mild-moderate fever helpful in speeding up repair processes in tissues

11. Immune Response Recognizes antigens and acts to inactivate or destroy them Antigen specific Acts against particular pathogens Systemic Not restricted to infection site Has a “memory” Recognizes and mounts stronger attacks on previously encountered pathogens

12. Antigens Substance that excites the immune system and provokes an immune response Foreign intruders are “non-self” Proteins Carbs; some lipids Nucleic acids Self-antigens don’t trigger immune response but do in other people Explains rejection of transplanted organs

13. Haptens An incomplete antigen A small (non-antigenic molecule) When it links up with the body’s proteins, body thinks it’s foreign These are what cause allergies!

14. Lymphocytes B and T cells B cells Mature in bone marrow Produce antibodies (Y-shaped) Oversee humoral immunity Antibody-mediated immunity T cells Mature in Thymus gland Help with cell-mediated response (don’t make antibodies) Immunocompetent When cells can respond to a specific antigen by binding to it

15. Lymphocytes, cont. Immunocompetent cells only recognize one antigen All receptors on the cell are the same Our genes determine what ‘germs’ we can recognize and resist When cells are immunocompetent, they travel to lymph nodes/spleen to mature Mature cells circulate the body in search of antigens

16. Macrophages “Big Eaters” Antigen presenters They engulf foreign particles and ‘present’ them like flags so T cells can recognize the antigens Secretes proteins called monokines Become “Killer Macrophages” in response to T-cell activation Stay in lymph organs

17. Humoral (Antibody-Mediated) Immunity Immature B cell is stimulated to mature when an antigen binds to its surface receptors Clonal selection begins B cell grows, multiplies to form an army of cloned cells Most of these become plasma cells Antibody-producing factories (produce 2,000 per second)

18. Humoral (Antibody-Mediated) Immunity B cell clones that don’t become plasma cells become memory cells Can respond to the antigen later Provide secondary response Faster and more effective, because attack plans have already been made

19. Active vs. Passive Humoral Immunity Active When B cells encounter antigens and produce antibodies against them Naturally acquired during infections Artificially acquired through vaccines Most vaccines contain dead or weakened viruses Vaccines keep you from getting most symptoms Vaccines still stimulate antibody production and memory of antigens Booster shots can intensify immunity later

20. Active vs. Passive Humoral Immunity Passive Antibodies are obtained from serum of immune human or animal B cells NOT challenged Memory does NOT occur Protection is temporary (ends when antibodies degrade in body) Natural Passive immunity When mom’s antibodies cross placenta into fetal circulation Artifical Passive immunity When someone receives immune serum/gamma globulin (Hepatitis, snake bites, botulism, rabies, tetanus)

21. Monoclonal Antibodies Produced by descendants of a single cell Are antibodies that are specific for one antigen Used to deliver cancer-fighting drugs Also used to diagnose Hepatitis, Pregnancy, Rabies, as well as for early cancer detection

22. Antibodies AKA Immunoglobulins (Ig’s) Blood proteins Proteins secrected by activated B cells or plasma-cell offspring in response to an antigen Capable of binding with that antigen Formed in response to antgens

23. Antibodies Made of 4 Amino Acid chains linked by disulfide bonds Two heavy chains and two light chains (1/2 the size of heavy chains) The chains combine to form the antigen-binding site that fits its specific antigen

24. Antibodies 5 classes (Remember “MADGE”) IgM; IgA; IgD; IgG; IgE IgD is virtually always attached to B cells IgG is only one that can cross placenta Also the most abundant IgA is found in mucus and other secretions IgM, IgG can fix complement IgE are “trouble-makers” in allergies

25. Antibody Function Inactivate antigens Complement fixation (activation) Triggers events that cause lysis of foreign cells Neutralization When antibodies bind to sites on foreign cells to cause cell injury Blocks harmful effects of toxins produced by bacteria/virus Agglutination Causes clumping of foreign cells (think Blood Transfusion reactions) Precipitation When antigen-antibody complexes are so big that they can’t stay dissolved in solution (makes them easily captured)

26. Cell-Mediated Immune Response T cells can’t bind with free antigens like B cells They must recognize an antigen presented by a macrophage AND “self” by binding to the macrophage The macrophage “feeds” antigens to the T cell (kind of like a double handshake)

27. Classes of T cell Clones Cytotoxic (Killer) T Cells Specialize in killing virus-infected, cancer cells, or foreign graft cells (inject toxic poison into CM) Helper T Cells “Directors/Managers” of Immune System Circulate and recruit other cells to fight Stimulate B cells to divide Signal for antibody production Release chemicals that rid body of antigens  Stimulate B and T cells to grow/divide  Attract more WBC’s to area  Enhance macrophage’s ability to destroy microbes (cause insatiable appetite for them)

28. Classes of T Cell Clones, cont. Suppressor T Cells Release chemicals that suppress activity of T and B cells Help wind down/stop immune response after the antigen is destroyed Delayed hypersensitivity T Cells Play a role in allergies and long-term inflammations Memory Cells Provide memory for each antigen encountered to allow the body to respond quickly next time

29. Organ Transplants 4 Types of Grafts Autografts Transplanted from one place to another in same person; IDEAL Isografts Tissue grafts donated by identical twin; IDEAL Allografts Taken from unrelated person; Blood Typing/antigen matching must happen (at least 75% match) Xenografts Harvested from another species; NEVER SUCCESSFUL Immunosuppressive Therapy Drugs, radiation (severe side effects) Body can’t protect itself against foreign antigens Most frequent cause of death is by bacterial/viral infection

30. Allergies AKA Hypersensitivities Abnormal vigorous immune response to a perceived “threat” that is harmless Allergen is a type of antigen that causes this response Immediate (acute) Hypersensitivity Runny nose, watery eyes, itching, hives, restricted air flow (inhaled allergen) Anaphalactic Shock When allergen directly enters bloodstream and travels through body Reaction involves the whole body

31. Allergies, cont. Delayed Hypersensitivity Take days to appear (1-3) Allergic contact dermatitis (poison ivy, contact with heavy metals, cosmetics, deodorant) Skin tests for TB depend on this type of reaction

32. Immunodeficiencies SCID (Severe Combined Immunodeficiency Disease) Congenital Not enough B and T cells Minor infections are lethal AIDS (Acquired Immunodeficiency Syndrome) Interferes with Helper T cell activity

33. Autoimmune Diseases Occurs when the body produces antibodies and T cells that attack and damage its own tissues Triggers Inefficient lymphocyte programming (self-reactive immune cells aren’t eliminated) “Hidden” antigens or “new self-antigens” caused by mutation or damage to cell Reaction of antibodies produced against foreign antigens with self-antigens (Strep antibodies can react with heart antigens and cause rheumatic fever)