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87 Cards in this Set
- Front
- Back
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Result of exposure of a host to a foreign substance:
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Active response
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2 major categories of Active immune responses:
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1. Innate
2. Adaptive |
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Main difference between adaptive and innate immunity:
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Adaptive = specific
Innate = nonspecific |
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Innate immunity components (10)
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Neutrophils/Eosinophils
Alternative complement pathway Mannan, Toll-like (TLR) and C3b receptors External barriers Normal flora Bile salts Low pH |
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Adaptive immunity components (3)
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-T lymphs
-B lymphs -Antibodies |
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5 components that are common to both adaptive and innate immunity:
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-Classical complement pathway
-Cytokines -Dendritic cells -Macrophages -Natural Killer cells |
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Timeframe over which Innate immunity operates:
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0 to 12 hours
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Timeframe over which Adaptive immunity operates:
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1 to 5 days
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What drives both the innate and adaptive immune systems?
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Receptor ligand interactions
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What do the receptors on cells of innate immunity recognize?
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Patterns of macromolecules on microbe surfaces
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PAMP
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Pathogen
Associated Molecular Pattern |
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What exactly are PAMPs?
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The identical ligands present on different microbes that are recognized by innate immune cells
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Where are receptors for both innate and adaptive immunity encoded?
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In germline DNA
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What happens to generate the specificity of the receptors in the adaptive immune cells?
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Gene rearrangement during cell differentiation
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So the 2 classes of Cell Surface Receptors are:
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1. Those encoded by rearranged genes (adaptive)
2. Those encoded by non-rearranged genes (innate) |
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2 types of receptors that belong to the rearranged, adaptive category:
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1. Tcell receptors for antigen
2. Antibody molecules (Igs) |
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7 types of receptors that belong to the nonrearranged, immune category:
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1. Mannose receptor
2. LPS receptor 3. Glucan receptor 4. Scavenger receptor 5. Complement receptor 6. TLR 7. Fc Receptor |
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What is innate immunity specific for?
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Structures shared by classes of microbes - molecular patterns
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What is Adaptive immunity specific for?
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Structural DETAIL of microbial molecules - antigens
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What is the distribution of innate receptors?
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-Nonclonal
-Identical receptors on all cells of the same lineage |
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What is the distribution of adaptive receptors?
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-Clonal
-Different clones have receptors specific for different antigens |
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Does innate immunity have discrimination of self and non?
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Yes
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Does adaptive?
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Yes
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What are the 4 main principles of adaptive immunity?
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1. Spcfc recgnitn of Ag by cell surface receptors on lymphs
2. Spcfc recgnition of Ag by Ag binding receptors on antibodies 3. Activation of 2ndary mechanisms 4. Memory |
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What are the 2 types of adaptive immunity?
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1. Humoral
2. Cell-mediated |
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What are the microbes combated by humoral immunity?
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Extracellular
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What lymphocyte responds for humoral immunity?
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B lymphs
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What is the effector mechanism for humoral immnity?
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Secreted antibody
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What are the microbes combated by cell-mediated immunity?
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-Phagocytosed microbes in macrophages
OR -Intracellular microbes replicating within infected cells |
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What are the cells that respond in cell mediated immunity?
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-Helper T cells
-Cytotoxic T cells |
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What do Thelper cells respond to?
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Macrophages containing phagocytosed microbes
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What do Tcytotoxic cells respond to?
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Cells infected with viruses
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What is the function of a Thelper cell binding to antigen presented on a macrophage?
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It activates the macrophage to kill the phagocytosed microbes.
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What is the function of a Tcytotoxic cell binding to antigen on a cell?
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It kills the infected cell and eliminates reservoirs of infection
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Why is Specificity significant for immunity to microbes?
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The body can recognize and respond to many different microbes
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Why is Memory significant for immunity to microbes?
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Because the body has enhanced responses to recurrent or persistent infections
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Why is Specialization significant for immunity to microbes?
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Because the body's responses to DISTINCT microbes are optimized for defense against these microbes.
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Why is Nonreactivity to Self Antigens significant for immunity to microbes?
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Because it prevents injurious immune responses against host cells and tissues.
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List the 5 phases of the Adaptive immune response:
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1. Recognition phase
2. Activation phase 3. Effector phase 4. Decline (homeostasis) 5. Memory RAED EM AND WEEP |
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What happens during the recognition phase?
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An APC presents antigen to the naive B and T lymphocytes
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What happens during the Activation phase?
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Expansion and differentiation of the mature T/B cells
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What are the 2 important results of the Activation phase?
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1. Antibody producing cells
2. Effector T lymphocytes |
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What happens during the Effector phase?
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Elimination of antigens by Humoral and Cell-mediated immunity
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What happens during the Decline phase?
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Apoptosis
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What happens during the memory phase?
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Surviving memory cells remain available for the next infection by the same pathogen
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Where do lymphocyte clones mature?
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In generative lymphoid organs in the ABSENCE of antigens
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What are clones of naieve lymphocytes specific FOR? What happens to THEM?
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Diverse antigens - they enter lymphoid tissues
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What happens to antigen-specific clones of lymphocytes in lymphoid tissues if their appropriate Ag is present?
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The clones are ACTIVATED (selected)
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So lymphocyte activation is essential and necessary for:
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Antigen-specific immune responses to occur.
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What is REQUIRED for lymphocyte activation?
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2 SIGNALS!!!
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What is signal 1?
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The microbial antigen binding to its antigen receptor on the lymphocyte
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What is signal 2?
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The costimulatory molecule produced or induced by the microbe
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What are the 3 principal cells of the immune system?
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1. Lymphocytes
2. APCs 3. Effector cells |
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What are the 3 varieties of lymphocytes?
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-B cells
-T cells -NK cells |
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What is the main principal function of lymphocytes?
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Specific recognition of antigens
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B lymphs mediate:
T lymphs mediate: NK cells mediate: |
B = humoral immunity
T = cell-mediated immunity NK = innate immunity |
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4 types of APCs:
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-Dendritic cells
-Macrophages -Follicular dendritic cells -B cells |
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What is the principal function of APCs?
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Capture of antigens for display to lymphocytes
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Dendritic cells are responsible for the initiation of:
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T cell responses
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Macrophages are responsible for:
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Initiation and the effector phase of cell-mediated immunity.
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Follicular dendritic cells are responsible for:
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The display of antigens to B lymphocytes in humoral immune responses
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What are 3 types of Effector cells?
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-T lymphocytes
-Macrophages -Granulocytes |
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What is the principal action of Effector cells?
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Elimination of antigens
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What are the 2 types of effector T lymphocytes?
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-Helper T cells
-Cytotoxic T cells |
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Which granulocytes are effector cells?
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Eos and Neuts
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What cells are capable of capture and degradation of antigens for Induction of the Immune response?
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-Dendritic cells
-Monocyte/macrophages -B cells |
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What is required for presentation of degraded Ag to T lymphocytes?
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MHC
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What cells have MHC class I?
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All nucleated cells
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What does MHC I activate?
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CD8 pos T cells (cytotoxic)
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What cells have MHC class II?
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Specialized cells
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What does MHC II activate?
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CD4 pos Thelper cells
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What can cause "DIRECT" presentation of foreign MHC molecules?
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-Transplantation reactions
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What are the 3 main steps in the B lymph humoral immune response?
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1. Binding native antigen to surface antibody
2. Activation via the Ag binding and cytokine signals from activated T cells 3. Differentiation into plasma cells to secrete Ab |
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What form of antigen do Bcells respond to?
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Native
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What form of antigen do Thelper cells respond to?
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Degraded + MHCII
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What form of antigen do Tcytotoxic cells respond to?
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Degraded + MHCI
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What form of antigen do NK cells respond to?
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Altered or no MHC I
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How do T lymphocytes get from the circulation into lymph nodes?
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Via high endothelial venules
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What size of proteins are more immunogenic?
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Large - larger than 2500 mw
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What dose of antigen is most immunogenic?
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Intermediate
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What is the most immunogenic route of entry for antigens?
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Subcutaneous
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What is the least immunogenic route of entry for antigens?
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Intravenous or intragastric
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What type of protein composition is most immunogenic?
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Complex
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What is the most immunogenic form of protein?
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Particulate and denatured
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Does one protein consist of only one, or several epitopes?
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Several
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What would be found in antiserum of an individual immunized with myoglobin which has four epitopes?
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4 antibodies, one for each epitope
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So when a person is immunized against the flu, for instance, will they develop antibodies and Tcells from only one clone?
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No, they may develop several specific clones for a large number of epitopes
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