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27 Cards in this Set
- Front
- Back
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two immune systems
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innate immunity and adaptive
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why do we need an immune system?
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- humans are a source of nutrients to invading viruses
- immune system fights off harmful cells |
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overview of innate immunity
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- rapid responding
- always the same response - general recognition of non-self (antigen) |
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overview of adaptive immunity
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- slower response
- very specific recognition of antigen an self molecules - adaptive response (second response) |
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barrier defenses of innate immunity
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- skin
- mucous membranes - secretions - stomach pH |
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cellular defenses of innate immunity
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- phagocytic cells
- antimicrobial proteins - inflammatory responses - natural killer cells |
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phagocytic cells
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- neutrophil (PMN): most numerous white blood cells. rapidly acting phagocyte.
- monocyte: in blood. becomes macrophage in tissues. - phagolysosome: combine and produce digestive enzymes |
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antimicrobial proteins
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- complement system: 30 proteins that act like a chemical death squad.
- interferon: anti-viral - lysozome: enzyme that breaks down the cell wall of bacteria. |
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inflammatory response
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- chemical signals released from damaged cells.
- capillary dilates - cells from blood leave and make way to damaged site. bring WBC |
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natural killers
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- attack virus infected self cells
- cancer cells - uses pattern recognition |
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cells of adaptive immunity
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- B lymphocytes (B cells): humoral immunity
- T cytotoxic lymphocytes (Tc cells): cell mediated immunity - T helper lymphocytes (Th): help turn on both HI and CMI |
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B cells
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- use antibody to specifically recognize antigen
- antibody is secreted from the cells. |
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T cells
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- use T cell receptors to recognize anitigen
- protein that is attached to the cell. |
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epitopes
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- the region on antigen that are specifically recognized by the antibody or TCR
- specific shape |
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antibody
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- secreted by the B cell
- must have a specific shape to bind to antigen - can only bind to free antigen - also called immunoglobulin |
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class I MHC
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- found on all nucleated cells (not red blood cells)
- present the antigen OR self molecules taht originated within the cell to Tc cells (like cancer cells or intracellular viruses) |
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class II MHC
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- found on "professional" antigen presenting cells (APCs)- mono/macs, dendritic cells, B cells
- present phagocytized or endocytized antigen to Th cells. |
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cell mediated immunity
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- professional APC's present antigen on class II MHC to Th cells
- TCR recognizes foreign antigen - CD4 recognizes self class II MHC - Th cells become activated - Will help start adaptive IR - against intracellular Ag |
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humoral response
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- infected or cancerous cells present antigen on class I MHC to Tc cells.
- CD8 recognizes self class I MHC - the Tc cell will be activated - the infected cell will be killed - against extracellular Ag - B cell lineage |
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adaptive immune response
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- antigen gets in
- inflamatory response - macs, dendritic cells travel to major immune organs, phagocytize antigen then travel via the circulatory system to immune organs. |
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major immune organs
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- spleen - blood filter
- lymph nodes - tissue and lymph fluid - other lymphoid organs |
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interaction between APC's and specific Th cells
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- APC presents antigen to Th cells
- Th cell is now antigen activated - Th cell produces cytokines that stimulate itself. - cytokines cause Th cells to divide and differentiate - produces effector memory Th cells, and memory Th cells (adaptive IR) |
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interaction between B cells and specific Th cells
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- B cell with correct antibody binds antigen
- presents Ag on class II MHC. B cell is now Ag activated. - effector Th cells recognizes Ag that B cell is presenting - Th cell produces cytokines - cytokines interact with B cell (paracrine) - B cell divides and differentitates |
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interaction between Tc cells and specific Th cells
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- Tc cell binds an infected cell
- TCR recognizes Ag - CD8 recognizes Class I MHC - Tc becomes Ag activated - cytokines from nearby Th cell (paracrine signaling) cause Tc cell to divide and differentiate. |
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what does antibody do?
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- neutralize: blocks the attachment of microorganisms or its products from binding to target tissue
- opsonization: helps phagocytize better. works with both immune systems. - complement activation |
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how do Tc cells kill target cells?
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- perforins: perforate. create pores in infected cell. loses control over membrane. dies.
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what happens when the immune system fails?
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- allergies: too much histamine (which causes immune system response)
- autoimmunity: the immune system attacks self - immunodeficiency: too little, or no immune system response (primary- inborn. secondary- acquired) |
