311DCh43 - Ch. 43 pg. 930-938 & 940-953 Innate Immunity...

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Innate Immunity – the first immunity present before any exposure to pathogens and effective from the time of birth Acquired immunity – adaptive immunity; develops after exposure to inducing agents such as microbes, abnormal body cells, toxins, or other foreign substances Lymphocytes – recognition is achieved by white blood cells Antibodies – secreted by B-lymphocytes that bind to microbes and mark them for elimination Cytotoxic lymphocytes – destroy infected body cells, cancer cells, or foreign tissue Lysozyme – antimicrobial protein; an enzyme that digests the cell walls of many bacteria; saliva, tears, mucous secretions Phagocytosis – ingestion of invading microorganisms by certain types of white blood cells (phagocytes); engulfs microbe forming a vacuole that fuses with a lysosome; NO poisons microbes; or enzymes degrade the microbial components Neutrophils – 60-70% of WBC; attracted to and then enter infected tissue, engulfing and destroying microbes there Macrophages – develop from monocytes; Eosinophils – low phagocytic activity; critical t defense against multicellular parasitic invaders Dendritic cells – can ingest microbes like macrophages do; stimulate development of acquired immunity Complement system – 30 serum proteins that are antimicrobial; in absence of infection these proteins are inactive; substances on the surface of microbes trigger a cascade that activates the complement system leading to lysis (bursting) of invading cells Interferon (alpha and beta) – provide innate defense against viral infections; secreted by virus infected body cells and induce neighboring uninfected cells to produce other substances that inhibit viral reproduction; destroys viruses like flu and cold Defensins – secreted by activated macrophages Inflammatory response – damage to tissue by physical injury or the entry of pathogens leads to release of numerous chemical signals Histamine – stored in mast cells found in connective tissues; mast cells release their histamine triggering dilation and increased permeability of nearby capillaries; promotes blood flow to injured site that supplies redness and heat of inflammation Chemokines – small proteins that direct the migration of phagocytes and signal them to increase production of microbe killing compounds Septic shock – certain bacterial infections can induce an overwhelming systemic inflammatory response; high fever; low blood pressure Natural Killer (NK) cells – patrol the body and attack virus infected body cells and
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This note was uploaded on 02/01/2011 for the course BIO 311D taught by Professor Reichler during the Spring '08 term at University of Texas at Austin.

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311DCh43 - Ch. 43 pg. 930-938 & 940-953 Innate Immunity...

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