Specific Host Defenses 1 – Flashcards
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Define immunology |
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the study of the immune system and immune responses |
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What is immunity? |
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resistance to infection |
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What are the 2 primary functions of the immune system? |
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- Identify self versus non self - Destroy non-self |
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What are antigens? |
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molecules that stimulate the immune system to product antibodies |
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What is an antibody? |
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proteins produced by lymphocytes in response to the presence of an antigen |
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What is Humoral immunity? |
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it involves the production of antibodies in response to antigens (protects against pathogens) |
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What is cell-mediated immunity? |
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involves various cell types with antibodies only playing a minor roll |
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What is acquired immunity? |
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immunity that results from the active production or recipient of production |
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Two areas of active acquired immunity and the definitions |
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Natural - exposed to antigen and your body has an immune response to it Artificial - injected with something that articificially makes an immune response (vaccines) |
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Passive acquired immunity: two of them and definitions |
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Natural: occur naturally; maternal antibodies Artificial: sera, gamma globulin - injected with gamma globulin (antibody made in an animal) |
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What are protective antibodies? |
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antibodies that protect us from infection or reinjection |
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TF all antibodies are effective at protecting |
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False |
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What are the two branches of the immune system? |
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Humoral Cell-mediated |
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What is humoral immunity |
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antibodies that work outside the cell: always involves the production of antibodies. Antibodies remain in blood plasma, lymph and protect against the pathogen that stimulated them |
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What is cell-mediated immunity |
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virus living inside the cell where antibodies can't attach to it. It involves macrophages, T helper cells, cytotoxic T cells, delayed hypersensitivity T cells, NK cells, killer cells and granulocytes |
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TF antibodies play a big role in cell mediated immunity |
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F |
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Define antibody |
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glycoprotein produced by plasma B cells via stimulus from antigens |
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What is an immunoglobulin |
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(antibody) globular like protein involved in the immune response |
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What is the structure of an antibody? |
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two heavy and two light chains |
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Where does the antibody have specific things for identification? |
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Variable regions |
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How many antigen binding sites do antibodies have? |
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2 |
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What are monoclonial antibodies? |
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purified antibodies made in lab for a single antigen. |
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What are monoclonial antibodies made from? |
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hybridoma (hybrid of plasma cell and tumor cell) |
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antibody classes: IgA |
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monomer or dimer, 10-20%: saliva, tears, colostrum, breast milk, mucous |
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antibody classes: IgD |
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found on surface of B cells. Function is unclear, maybe an antigen receptor? |
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antibody classes: IgE |
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Allergic responses on surface of basophils or mast cells |
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antibody classes: IgG |
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Most abundant (naturally acquired) - only class that can cross placenta - Long lived - activate complement - bind cellular receptors |
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antibody classes: IgM |
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pentamer (10%): high binding capacity - first antibodies made during primary response - bind 10 antigens each - short-lived |
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Define antigen |
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any foreign substance able to stimulate antibody production |
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What does antigenic mean? |
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substances are capable of producing antibodies |
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What does immunogenic mean? |
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generate antibodies that help to keep you healthy |
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Antigenic determinants (AKA and definition) |
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epitopes: molecules on surface of antigen that are capable of stimulating the production of antibodies |
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Haptens |
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act as antigens only if they are coupled with large carrier molecules (they are too small to work on their own) |
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What is the primary response? |
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initial response to an antigen |
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What happens during the primary response? |
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plasma cells multiply, and some become memory cells or plasma cells |
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What is the secondary response? |
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the increased production of antibodies after the second exposure to the antigen |
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What are the antibody producing cells? |
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B cells |
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What cells are involved in humoral immunity |
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B cells --> plasma cells, T helper cells, memory cells |
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Agammaglobulinemia |
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failure to produce antibody in response to antigen |
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hypogammaglobulinemia |
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low levels of antibody production (have B cells that don't work) |
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How do antibodies protect us? 5 |
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prevent attachment, neutralize toxins/viruses, opsonize (candy coat for phagocytosis), activate complement system, Activate NK cells |
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What are the 3 locations of immune responses? |
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spleen, lumph nodes, tonsils/adenoids |
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What are the cells of the immune system? |
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T cells (T helper/ T cytotoxic), B cells (plasma and memory), NK cells, macrophages |
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What are vaccines |
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materials that artificially induce immunity to a pathogen |
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How can vaccines be delivered? |
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injected or ingested |
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What two things do vaccines produce? |
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protective antibodies and memory cells |
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What 4 qualities does the ideal vaccine contain? |
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contains enough antigens to yield protective antibodies, covers all strains, few/no side effects, does not cause disease |
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Types of vaccines: Live Attenuated |
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live organism is weakened, mutant, avirulent |
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Examples of live attenuated vaccines |
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varicells, measles, mumps, polio, BCG, cholera |
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Types of vaccines: inactivated |
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organism is killed by heat or chemicals, not as good as live |
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Examples of inactivated vaccine |
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HepA, influenza, viral encephalitis, anthrax |
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Types of vaccines: subunit |
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a cellular, antigenic portion of pathogen (use the purified protein) |
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examples of subunit vaccines |
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HepB, lyme disease, pertussis |
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Types of vaccines: conjugate |
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attach capsule antigens to a carrier protein (to get a good antibody response) |
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Examples of conjugate vaccines |
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Hib, meningococcal, pneumococcal |
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Types of vaccines: Toxoid |
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inactivated bacterial toxin (for bugs that are more driven by the toxin) |
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Examples of toxoid vaccine |
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diphtheria, tetanus |
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Types of vaccines: DNA |
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plasmid with pathogen gene: experimental |
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What is cell-mediated immunity? |
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controls infections of intracellular pathogens |
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What are the interactions of cell mediated immunity between? |
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between many types of cells and cytokines |
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What do macrophages do? |
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engulf, kill, present antigen to T helper |
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What do T helper cells do? |
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secrete cytokines, signal other cells (intermediate that call in reinforcement) |
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What do effector cells do? What are 2 effector cells |
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kill infected cells - T cytotoxic - Natural Killer: they target cells, foreign/host cells infected with virus or tumor cells |
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Cell mediated immunity: response to infection: macrophage |
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phagocytoses, digests pathogen. They then display pathogen antigen epitopes in MHC |
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Cell mediated immunity: response to infection: TH cell |
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they bind to the antigen:MHC complex, producing cytokines |
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Cell mediated immunity: response to infection: Cytokines |
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Recruit/activate effector cells |
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Cell mediated immunity: response to infection: Effector cells |
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binds to target cell displaying same Ag:MHC, contents of effector cells are discharged, Toxins enter and kill infected target cell |
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Left off on slide 15 |
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What is hypersensitivity |
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overly sensitive immune system |
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What does hypersensitivity cause? |
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irritation or damage |
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What cells does a hypersensitivity reaction involve? |
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Ag and T cells (SOMETIMES antibodies, depending on what antigen is present) |
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Time frame for immediate hypersensitivity reaction |
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within minutes to 24 hours |
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Delayed hypersensitivity reaction |
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>24 hours, cell mediated that takes longer to recruit cells |
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Look at slide 16: type 1 hypersensitivity reaction |
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n/a |
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What happens in a type 1 hypersensitivity? |
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IgE antibodies and release chemical mediators from mast cells and basophils. |
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What is an alelrgen |
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antigen that cause sensitivity |
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Allergic response: 1st exposure |
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sensitizes cells with IgE (antibody) |
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Allergic response: 2nd exposure |
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allergen triggers degranulation |
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Localized anaphylaxis is due to what cells? |
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mast cells (hay fever) symptom depends on how it enters the body |
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Systemic anaphylaxis is due to what cells? |
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basophils (drugs, insect bite). Anaphylactic shock results form the release of chemical mediators from basophils in the bloodstream |
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Latex allergy |
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irritant contact dermatitis, allergic contact dermatitis, and latex allergy |
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When is allergy skin testing considered positive? |
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if cutaneous anaphylaxis occurs |
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What is the purpose of allergy shots? science-ie description |
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try to get IgG response before it gets to the IgE |
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Type 2 hypersensitivity |
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cytotoxic reactions (body cells are destroyed) antibodies are recognizing own cells and working to kill them |
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What is the process of type 2 hypersensitivity? |
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antigen (ie drug) binds to cell surface, antibody binds to the bound antigen, antibody binding initiated complement activation, complement cascade lyses cell. |
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When doe type 2 hypersensitivity occur? |
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incompatible blood transfusions and Rh factor incompatability |
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Type 3 hypersensitivities |
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immune complex reactions ( Ag+Ab+C) |
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What are immune complexes the result of? |
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binding of an antibody with the antigen that stimulated its production |
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Why are antigen-antibody complexes bad? |
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they can get stuck in kidneys and trigger complement activation and cause destruction to these tissues |
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What can type 3 hypersensitivity cause |
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tissue damage, serum sickness, autoimmune disease, fever, rash, kidney malfunction, heart damage |
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Type 4 hypersensitivity |
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delayed type hypersensitivity |
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What type of immune system mechanism does type 4 hypersensitivity work through? |
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cell-mediated reaction |
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What are 2 examples of type 4 |
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tuberculin, fungal skin tests |
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Transplant rejection occurs in what hypersensitivity? |
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4 |
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What is the process of type 4? |
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- influx of PNMs within 2-3 hours of injection - PNMs disperse; followed by lymphocytes and macrophages - Area becomes red w/in 12-18 hours - Erythema (redness) peaks between 24-48 hours - With time, swelling/redness disappear |
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What happens in an autoimmune disease? |
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immune system fails to recognize self and attacks body tissue as if it were foreign |
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What can cause autoimmune diseases? 2 |
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tissue not exposed to immune system during fetal development or your own cells are altered by drugs or viruses. |
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What are autoimmune diseases a result of? |
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type 2 3 4 hypersensitivity |
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Ex of organ specific autoimmune disease |
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diabetes |
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Non-organ specific autoimmune diseases |
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affect skin, kidneys, joints, myasthenia gravis, SLE, RA (antibodies are floating around and deposit wherever blood takes them) |
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What are the causes of immunosuppression? |
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malnutrition, acquired immunodeficiencies, inherited immunodeficiencies |
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what are acquired immunodeciciencies |
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drugs, irradiation, HIV |
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What are inherited immunodeciciencies |
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lack of antibody, complement, phagocytic or NK function, chronic granulomatous disease, SCID, DiGeorge syndrome, Wiskott-Aldrich syndrome |
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What is DiGeorge syndrome |
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no thymus, parathyroid |
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What is Wiskott-Aldrich syndrome |
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no B/T cells, monocytes and platelets |
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What can detection of antibodies tell you? |
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indicate present or past infection or vaccination |
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What antibody do you test for? |
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IgM: you look at acute serum and convalescent serum. then you look for antigens |