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What are the examples of the first line of defenses that the rhinovirus escaped?
Mucus and cilia
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What is an example of the second line of defense that functions in surveillance?
Dendritic cells
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What are epitopes?
- Rhinovirus fragments
- The site on an antigen at which a specific antibody becomes attached
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What are the 3 main lines of defense, and which ones are innate?
- First Line of Defense - Physical barrier (innate/nonspecific)
- Second Line of Defense - cells chemicals, processes (innate/nonspecific)
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First Line of Defense - Physical barrier (innate/nonspecific)?
- skin
- mucous membranes
- lacrimal apparatus
- normal microbiota
- defensins
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First Line of Defense - Physical barrier (innate/nonspecific)
Skin?
- 1) Epidermis - physical barrier of tightly packed cells, surface of dead cells are sloughed off, carrying microbes away. Dendritic cells - phagocytic, present antigens for adaptive immun.
- 2) Dermis - collagen makes a tough protective layer: Blood vessels deliver defensive cells and chemicals. Sweat from sweat glands: salt, lysozyme, defensins. Sebum from oil glands: lowers pH
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First Line of Defense - Physical barrier (innate/nonspecific)
Mucous Membranes?
- Epithelial cells continuously shed, carry microbes away
- Dendritic cells
- Goblet cells secrete mucus - traps pathogens, contains lysozyme, defensins
- Cilia remove mucus and pathogens
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First Line of Defense - Physical barrier (innate/nonspecific)
Lacrimal apparatus?
produces and drains tears, blinking spreads tears, washes surface of eyes, tears contain lysozyme
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First Line of Defense - Physical barrier (innate/nonspecific)
Normal microbiota?
- 1) microbial antagonism
- 2) consume nutrients,
- 3) change pH
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First Line of Defense - Physical barrier (innate/nonspecific)
Defensins?
- antimicrobial peptides, act against a variety of pathogens in several ways:
- punch holes in cytoplasmic membranes
- interrupts signaling
- interrupt enzyme action
- chemotactic
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific)?
- Defensive Cells - Leukocytes
- Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells
- Defensive Chemicals
- Inflammation- nonspecific response to tissue damage
- Fever- body temp above 37oC
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):
Defensive Cells - Leukocytes?
- 1. Granulocytes- squeeze out of BV by diapedesis
- Basophils
- Eosinophils
- Neutrophils
- 2. Agranulocytes:Lymphocytes
- Monocytes
- Dendritic cells
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Basophils?
secrete histamines (inflammation)
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Eosinophils?
phagocytic and secrete antimicrobial chemicals, kill worms, parasites
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Neutrophils?
phagocytic and secrete antimicrobial chemicals, kill bacteria
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Lymphocytes?
- Natural Killer Cells (innate/nonspecific immunity)
- T cells, B cells (adaptive/specific immunity)
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Monocytes?
- when leave blood stream become macrophages - phagocytic
- wandering
- fixed: alveolar macrophages, microglia, Kupffer cells
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Dendritic cells?
phagocytic, mostly in skin, mucous membranes
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):
Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
- Chemotaxis
- Adherence
- Ingestion
- Killing
- Elimination
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Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
Chemotaxis?
- -chemicals attract phagocytes towards pathogen
- Microbial components
- Damaged tissue
- White blood cells
- Chemotactic factors: defensins, complement, chemokines
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Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
Adherence?
- Bacterial virulence factors that hinder adherence:
- M protein
- Capsules or slime layer
- Opsonization- when complement protein or antibodies enhance adherence and phagocytosis
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Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
Ingestion?
microbe encased in phagosome
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Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
Killing?
phagosome fuses with lysosome, which contains digestive enzymes
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Phagocytosis by eosinophils, neutrophils, macrophages, dendritic cells?
Elimination?
- exocytosis
- Fragments of pathogen may be displayed on outer surface of cytoplasmic membrane of phagocytic cell - part of adaptive immunity
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific)
Nonphagocytic Killing?
- Eosinophils and neutrophils secrete
- antimicrobial/toxic chemicals
- Natural Killer lymphocytes (NK cells) secrete toxins to kill virally-infected cells and cancer cells
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):
Defensive Chemicals?
- Toll-like receptors (TLRs)
- NOD proteins
- Interferons
- Complement System
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):Defensive Chemicals
Toll-like receptors (TLRs)?
membrane proteins of phagocytic cellsreact to pathogen associated molecular patterns (PAMPs)Initiates defensive response including apoptosis
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):Defensive Chemicals
NOD proteins?
- receptors for PAMPs inside the cell
- Trigger inflammation, apoptosis
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):Defensive Chemicals
Interferons?
- proteins released by host cell infected with virus
- Activate NK cells
- Triggers neighboring cells to produce antiviral proteins
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):Defensive Chemicals
Complement System ?
- serum proteins trigger cascade of events, results in...
- opsonization for phagocytosis
- chemotaxis for defensive cells
- membrane attack complex (MAC)
- histamine release by basophils, platelets, or mast cells
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific)
Inflammation - nonspecific response totissue
damage?
- Signs and symptoms:
- 1) Redness
- 2) localized heat
- 3) edema
- 4) pain
- Results in:
- 1) Dilation and increased permeability of blood vessels
- 2) Migration of phagocytes and other WBCs
- (neutrophils first, followed by monocytes - margination and diapedesis
- 3) Tissue repair
- 4) Increased blood flow to area brings oxygen and nutrients
- Chemical Mediators of Inflammation
- c.Histamine- secreted by basophils, platelets and mast cells
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Second Line of Defense - cells, chemicals, processes (innate/nonspecific):
Fever -body temp above 37oC?
- controlled by hypothalamus
- occurs when pyrogens are released - any fever causing chemicals, body starts to chiver, metabolic rate increases (HR increases), blood vessels constrict
- when pyrogens decrease, thermostat resets, body starts to perspire, metabolic rate
- slows, blood vessels dilate = crisis of fever
- Enhances effects of interferons
- Inhibits growth of microbes
- Probably enhances activity of white blood cells
- Helps tissue repair
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