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TORTORA ⏐ FUNKE ⏐ CASE ninth edition MICROBIOLOGY an introduction 16 Innate Immunity: Nonspecific Defenses of the Host PowerPoint® Lecture Slide Presentation prepared by Christine L. Case Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nonspecific Defenses of the Host Susceptibility: Lack of resistance to a disease. Immunity: Ability to ward off disease. Innate immunity: Defenses against any pathogen. Adaptive immunity: Immunity, resistance to a specific pathogen. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Host Defenses Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.1 Physical Factors Skin Epidermis consists of tightly packed cells with Keratin, a protective protein Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Physical Factors Mucous membranes Ciliary escalator: Microbes trapped in mucus are transported away from the lungs. Lacrimal apparatus: Washes eye. Saliva: Washes microbes off. Urine: Flows out. Vaginal secretions: Flow out. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.4a Chemical Factors Fungistatic fatty acid in sebum. Low pH (3-5) of skin. Lysozyme in perspiration, tears, saliva, and tissue fluids. Low pH (1.2-3.0) of gastric juice. Transferrins in blood find iron. NO inhibits ATP production. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Normal Microbiota Microbial antagonism/competitive exclusion: Normal microbiota compete with pathogens. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formed Elements in Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 16.1 (1 of 2) Formed Elements in Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 16.1 (2 of 2) Differential White Cell Count Percentage of each type of white cell in a sample of 100 white blood cells. Neutrophils 60-70% Basophils 0.5-1% Eosinophils 2-4% Monocytes 3-8% Lymphocytes 20-25% Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings White Blood Cells Neutrophils: Phagocytic Basophils: Produce histamine Eosinophils: Toxic to parasites and some phagocytosis Dendritic cells: Initiate adaptive immune response Monocytes: Phagocytic as mature macrophages Fixed macrophages in lungs, liver, and bronchi Wandering macrophages roam tissues. Lymphocytes: Involved in specific immunity. PLAY Animation: Host Defenses Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Phagocytosis Phago: from Greek, meaning eat Cyte: from Greek, meaning cell Ingestion of microbes or particles by a cell, performed by phagocytes. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.6 Phagocytosis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.7 Microbial Evasion of Phagocytosis Inhibit adherence: M protein, capsules Streptococcus pyogenes, S. pneumoniae Kill phagocytes: Leukocidins Staphylococcus aureus Lyse phagocytes: Membrane attack complex Listeria monocytogenes Escape phagosome Shigella Prevent phagosome-lysosome HIV fusion Survive in phagolysosome PLAY Coxiella burnetti Animation: Phagocytosis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Inflammation 1. Redness-rubor 2. Pain-dolor 3. Heat-calor 4. Swelling (edema)-tumor Acute-phase proteins activated (complement, cytokine, and kinins) Vasodilation (histamine, kinins, prostaglandins, and leukotrienes) Margination and emigration of WBCs Tissue repair Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemicals Released by Damaged Cells Histamine Vasodilation, increased permeability of blood vessels Kinins Vasodilation, increased permeability of blood vessels Prostaglandins Intensity histamine and kinin effect Leukotrienes Increased permeability of blood vessels, phagocytic attachment Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Inflammation Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.8a–b Inflammation PLAY Animation: Inflammation Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.8c–d Fever: Abnormally High Body Temperature Hypothalamus normally set at 37°C. Gram-negative endotoxin cause phagocytes to release interleukin–1 (IL–1). Hypothalamus releases prostaglandins that reset the hypothalamus to a high temperature. Body increases rate of metabolism and shivering which raise temperature. When IL–1 is eliminated, body temperature falls (crisis). Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fever Advantages Disadvantages Increase transferrins Tachycardia Increase IL–1 activity Acidosis Dehydration Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Complement System Serum proteins activated in a cascade. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.9 Effects of Complement Activation Opsonization or immune adherence: Enhanced phagocytosis. Membrane attack complex: Cytolysis. Attract phagocytes. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.10 Effects of Complement Activation Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.11 Classical Pathway Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.12 Alternative Pathway Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.13 Lectin Pathway Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.14 Some Bacteria Evade Complement Capsules prevent C activation. Surface lipid-carbohydrates prevent MAC formation. Enzymatic digestion of C5a. PLAY Animation: The Complement System Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Interferons (IFNs) Alpha IFN and Beta IFN: Cause cells to produce antiviral proteins that inhibit viral replication. Gamma IFN: Causes neutrophils and macrophages to phagocytize bacteria. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Interferons (IFNs) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 16.15 Innate Immunity Transferrins Bind serum iron Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antimicrobial peptides Lyse bacterial cells
