Unit 3- Non-Specific Resistance (Innate Immunity) Flashcards Preview

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Flashcards in Unit 3- Non-Specific Resistance (Innate Immunity) Deck (80):
1

innate immunity

defense mechanisms present at birth

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acquired immunity

defense mechanisms acquired by exposure to pathogens

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first line of defense

surface protection, anatomical/physiolgoical, genetic barriers, non-specific chemical barriers

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second line of defense

cellular and more specific chemical barriers

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third line of defense

specific immune response developed against individual pathogens

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physical barrier of respiratory tract?

epithelial tissue lining along the tract

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chemical barrier of respiratory tract?

mucous secreted into tract

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anatomical barrier of respiratory tract?

hair-like cilia sweeping mucous out of tract

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what line of defense are T and B lymphocytes, and antibodies?

third line

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what line of defense are phagocytosis, inflammation, fever and interferon?

second line

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what are 3 behaviours that act as 1st line barrier?

hygine, contagion avoidance, healthy choices (avoid high-risk behaviours)

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what are 2 physical first line barriers?

1) skin
2) mucous/wax (lines portals of entry)

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what are 3 chemical barriers of 1st line defense?

1) acid (stomach, lactic)
2) salt (tears, sweat)
3) proteins (lysozymes and defensins in tears, digestive enzymes)

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mechanism of lysozymes?

targets peptidoglycans of bacterial cell wall (non-specific defense)

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Example of how some have a 1st line genetic barrier to HIV?

HIV-1 R5 requires CCR5 receptor to infect cells, but some Caucasian populations have a 32 bp deletion in the CCR5 gene, conferring to some resistance to infection

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how does H.pylori overcome physical barriers of body?

uses flagellum to burrow into mucosal layer

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how does H.pylori overcome chemical barriers of the body?

it produces basic NH4+ through urease to neutralize stomach acid

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How does H. pylori overcome genetic barriers of the body?

It is well-adapted to survive in the human stomach

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what are WBCs/leukocytes

cells of the immune system; they recognize non-self cells and molecules

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which leukocytes are not active at birth?

B-cells and T-cells. all other leukocytes are part of the innate immune system and are active at birth

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what is the common stem cell WBCs and RBCs share?

hematopoietic stem cell

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what 4 locations can WBCs be found in?

1) bloodstream
2) lymphatic vessels
3) reticuloendothelial system (mesh-like network of connective tissue holding tissues together)
4) extracellular fluid

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what are the components blood separates into after centrifugation?

plasma (blood minus cells), buffy coat (WBCs), red blood cells (unclotted)

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what is serum?

plasma minus clotting proteins

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Neutrophil (class, action)

most abundant WBC, first responder, granulocyte, phagocytic (polymorphonuclear cell)

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what are PRR?

pattern recognition receptors (special proteins) that can feel abnormal proteins on non-self cells

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PAMPs?

pathogen associated molecular patterns (abnormal proteins on invading cells)

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TLRs?

toll-like receptors, whcih are special PRRs (pattern recognition receptors) that are on phagocytes (neutrophils, macrophages)

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lysosome?

destructive body

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phagolysosome?

an eating and destructive body

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7 steps of phagocytosis?

1) PRRs recognize PAMPs
2) phagocytic cell engulfs pathogen
3) bubble forms inside the cell- phagosome
4) destructive chemicals/enzymes stored in lysosomes and granuals
5) phagolysosome forms (fused together)
6) digestion and nutrient absorption into the cell
7) waste is excreted from cell

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phagocytosis results in...

intracellular killing of microbes

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what is the oxygen-dependent mechanism of intracellular killing of microbes?

toxins are called reactive oxygen species (either OH radicals or hypochlorite)

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what is the oxygen-independent mechanism of intracellular killing of microbes?

electrically charged proteins damage membrane, lysozymes damage cell wall, lactoferrins compete for Fe binding, proteases digest and degrade proteins

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what is a platelet?

a thrombocyte, is anucleate, and a fragment of a larger cell, megakaryocyte. it aggregates to seal up fissures in the blood vessels and skin to form blood clots or scabs

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chemokine

chemical signal released by neutrophils to attract monocytes and macrophages by chemotaxis. coordinates 2 effects of inflammation: vasoactive or chemotactic effects

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chemotaxis

process where neutrophils send chemokines to attract monocytes and macrophages

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monocyte

have granules, but NOT granulocytes, are the largest WBCs, are phagocytic, and produce cytokines, leading to inflammation. (premature form of macrophages)

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eosinophil

granulocyte, non-phagocytic, releases peroxides, lysozymes and toxins into invader and targets fungi, worms that are too large to consume. involved in allergy/inflammation

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4 parts of 2nd line defense of inflammation?

1) rubur (redness)
2) calor (warmth)
3) tumor (swelling)
4) dolor (pain)

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vasoactive actions

vasodilation, vasoconstriction

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chemotactic actiosn

cells migrate to site of damage, mediators released, phagocytes

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substances with chemotactic effects

endotoxins, platelet activating factor, leukotriene, mast cell chemotactic factors, bacterial peptides, PAMPs, endotoxin

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substances with vasoactive effects

histamine, serotonin, bradykinin, prostaglandins

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substances with both vasoactive and chemotactic effects

complement components, cytokines such as interferon and interleukin, arachidonic acid metabolism products, platelet activators

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histamine

formed by basophils and mast cells, released from granules and act quickly

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prostaglandin

from basophils and mast cells; made when needed and act slowly

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serotonin

invovled in intestinal movements and happy feelings after feeding. secreted by platelets to induce blood clotting

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bradykinin

increases sensation of pain, and vasodilation

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steps of 2nd line inflammation

1) margination
2) diapedisis
3) chemotaxis

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margination

endothelial cells of blood vessels express ICAMs (intercellular adhesion molecules) and stick to WBCs in teh damaged area

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ICAMs

intercellular adhesion molecules

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diapedesis

endothelial cells shrink and there's an opening

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chemotaxis

WBCs are pulled through the opening, and attracted to the site of infection

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name 3 chemical mediators of immunity

1) TNF- tumor necrosis factor
2) IFN- interferon
3) IL- interleukins (IL-1, IL-6, IL-8, IL-12)

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TNF

tumor necrosis factor made by macrophages, T and B cells to increase chemotaxis, phagocytosis, temperature. also involved in weight loss

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IFN

interferon: made by leukocytes, fibroblasts, and is an anti-viral/anti-tumor

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IL

interleukins, made by leukocytes and others
1) IL-1: vasodilation, B/T cell activation, pyrogen
2) IL-6: B/T cell activation, pyrogen
3) IL-8, chemotactic, non-pyrogenic
4) IL-12, activates NK cells and T helper cells, non-pyrogenic

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which interleukins are pyrogenic?

IL-1, IL-6

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which interleukins activate B/T-cells

IL-1, IL-6

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which interleukins are non-pyrogenic

IL-8, IL-12

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cytokine storm?

a systemic induction of cytokines, leads to shock

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what is the complement system?

a complex of proteins that pokes a hole in the surface of the cell; it is vasoactive and chemotactic, increasing inflammatory response

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where are complement proteins produced?

in teh liver

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what is an APP

acute phase protein- a protein that increases many-fold during early stage inflammation

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3 complement pathways?

1) classical pathway
2) MB-Lectin Pathway
3) Alternate Pathway

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classical pathway

complement-fixing antibodies (C3--> C3b)

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MB-Lectin pathway

sugars on teh surface of pathogens is binded by mannose-binding lectin (nonspecific for bacteria and viruses)

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Alternate pathway

C3 binds pathogens directly, molecules on surfaces of bacteria, fungi, viruses and parasites (nonspecific)

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what do all the pathways end up at?

C3--> C3b

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C5b does what to the membrane?

starting point for polymerization of a pore through membrane: MAC

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MAC

membrane attack complex (pore through the membrane)

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what does C3b do?

coverts C5--> C5b

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C3a and C5a?

involved in inflammation, chemokine

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C3b and C5b?

phagocytosis, opsonization

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what does C5b also lead to?

induces binding of C6, C7, C8

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what is an opsonin?

any protein that opsonizes the cell

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which complement proteins induces opsonization?

C3b, C5b

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what does C9 do?

complete the pore complex (MAC)

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Complement Fixation Test for H1N1 antigen

add Abs to H1N1 to sheep rBCs, heat pt serum to destry complement, and add H1N1 antigen, add complement factors and sheep RBCs. if complement binds serum Abs, means pt has produced Abs to the H1N1 antigen (Abs are not denatured with heat). If lysis is observed, the complement had binded to the sRBC Abs because there are no serum Abs present--> pt does not have H1N1 strain