ninth edition TORTORA FUNKE CASE M I C R O B I O L O G Y · 2008-05-19 · fluids. Low pH (1.2-3.0)...
Transcript of ninth edition TORTORA FUNKE CASE M I C R O B I O L O G Y · 2008-05-19 · fluids. Low pH (1.2-3.0)...
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
M I C R O B I O L O G Ya n i n t r o d u c t i o n
ninth edition TORTORA ⏐ FUNKE ⏐ CASE
16Innate Immunity:
Nonspecific Defenses of the Host
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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.
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Host Defenses
Figure 16.1
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Physical Factors
Skin
Epidermis consists of tightly packed cells with
Keratin, a protective protein
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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.Figure 16.4a
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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.
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Normal Microbiota
Microbial antagonism/competitive exclusion: Normal
microbiota compete with pathogens.
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Formed Elements in Blood
Table 16.1 (1 of 2)
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Formed Elements in Blood
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Neutrophils 60-70%
Basophils 0.5-1%
Eosinophils 2-4%
Monocytes 3-8%
Lymphocytes 20-25%
Differential White Cell Count
Percentage of each type of white cell in a sample of
100 white blood cells.
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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
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Phagocytosis
Phago: from Greek,
meaning eat
Cyte: from Greek,
meaning cell
Ingestion of microbes
or particles by a cell,
performed by
phagocytes.
Figure 16.6
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Phagocytosis
Figure 16.7
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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 fusion
HIV
Survive in phagolysosome Coxiella burnetti
Microbial Evasion of Phagocytosis
PLAY Animation: Phagocytosis
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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
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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
Chemicals Released by Damaged Cells
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Inflammation
Figure 16.8a–b
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Inflammation
PLAY Animation: Inflammation
Figure 16.8c–d
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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).
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Fever
Advantages
Increase transferrins
Increase IL–1 activity
Disadvantages
Tachycardia
Acidosis
Dehydration
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The Complement System
Serum proteins
activated in a
cascade.
Figure 16.9
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Effects of Complement Activation
Opsonization or
immune adherence:
Enhanced
phagocytosis.
Membrane attack
complex: Cytolysis.
Attract phagocytes.
Figure 16.10
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Effects of Complement Activation
Figure 16.11
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Classical Pathway
Figure 16.12
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Alternative Pathway
Figure 16.13
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Lectin Pathway
Figure 16.14
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Some Bacteria Evade Complement
Capsules prevent C activation.
Surface lipid-carbohydrates prevent MAC formation.
Enzymatic digestion of C5a.
PLAY Animation: The Complement System
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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.
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Interferons (IFNs)
Figure 16.15
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Innate Immunity
Transferrins
Bind serum iron
Antimicrobial peptides
Lyse bacterial cells