Lecture 5 Flashcards

1
Q

What are the key components of the innate immune response?

A

Barriers, Sentinel cells in tissue, circulating phagocytes and granulocytes, blood proteins, cytokines

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2
Q

Sentinel cells in tissues

A

Dendritic cells, macrophages, natural killer cells

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3
Q

What do circulating phagocytes and granulocytes do?

A

Cells that can recognize groups of pathogens (ingest foreign matter)

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4
Q

Examples of circulating phagocytes and granulocytes

A

Neutrophils, monocytes, eosinophils, basophils

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5
Q

What do blood proteins do?

A

Mediate inflammation

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6
Q

What do cytokines do?

A

Signal, stimulate, and regulate the immune response

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7
Q

Barrier: saliva properties

A

Antibacterial enzymes

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8
Q

Barrier: tears properties

A

Antibacterial enzymes

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9
Q

Barrier: skin properties

A

Prevents entry

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10
Q

Barrier: mucus properties

A

Lining traps dirt and microbes

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11
Q

Barrier: stomach acid properties

A

Low pH kills harmful microbes

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12
Q

Barrier: “good” gut bacteria properties

A

Out compete the bad bacteria (kills it)

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13
Q

What are the main sites of interaction between individuals and their environment?

A

Skin, GI tract, Respiratory tract, and the Genitourinary tract

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14
Q

Role of epithelial cells

A

Defence against pathogens

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15
Q

What makes up the epithelial barrier?

A

Tight junction, Mucous, and Keratin layers (physical barrier)

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16
Q

Defensins

A

Host defence peptides with either direct antimicrobial activity, immune signalling activities, or both

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17
Q

Cathelicidins

A

A polypeptide that is primarily stored in the lysosomes of macrophages and polymorphonuclear leukocytes

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18
Q

Where do all immune cells originate

A

Bone marrow

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19
Q

Phagocytes’ objective:

A

Identify, ingest and destroy pathogens

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20
Q

The role of a Phagocyte

A

Recognition of microbes (PRR), Ingestion of microbe by phagocytosis, Destruction of ingested microbe, Secretion of cytokines to promote and/or regulate immune response, Recruitment of cells to site of infection

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21
Q

Examples of professional phagocytes

A

Marcophages and neutrophils

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22
Q

Where are macrophages found?

A

Present under your skin, tissues in lungs and intestines

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23
Q

Macrophages found in bone:

A

Osteoclasts

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24
Q

Macrophages found in the central nervous system

A

Microglia

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25
Q

Macrophages found in connective tissue

A

Histiocytes

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26
Q

Macrophages found in the chorion villi of the placenta

A

Hofbauer cells

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27
Q

Macrophages found in the kidney

A

Mesangial cells

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28
Q

Macrophages found in the liver

A

Kupffer cells

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29
Q

Macrophages found in the peritoneal cavity

A

Peritoneal macrophages

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30
Q

Macrophages found in the pulmonary airway

A

Alveolar macrophages

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31
Q

Macrophages found in the skin

A

Epidermal and dermal macrophages

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32
Q

Macrophages found in the spleen

A

Marginal zone macrophages, metallophilic macrophages, red pulp macrophages, and white pulp macrophages

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33
Q

What stages do macrophages exist?

A

Resting (patrolling mode), activated (antigen presentation mode), hyperactivation (destroyer mode)

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34
Q

Resting macrophage stage

A

Digest dead/non-functional cells and wound healing

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35
Q

Activated macrophage stage

A

Upregulation of antigen molecules (MHC 1/2), Invaders are destroyed and pieces are displayed to activate T cells

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36
Q

Hyperactivation macrophages stages

A

Increased in size to focus on destruction (increased lysosomes)

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37
Q

Neutrophils

A

Most abundant white blood cells (40-70%) specialized for killing

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38
Q

How long is the life span of a neutrophil

A

Short (5-7 days)

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39
Q

Monocytes

A

Circulate in blood to be recruited to sites of infection to mature into macrophages

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40
Q

Where are NK cells found?

A

Blood, spleen, and liver

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41
Q

What is the role of NK cells

A

“on call” and recruited to the sites of infection, produced cytokines to help in pathogen defence and activation of macrophages. They destroy infected/cancerous cells/parasites/bacteria/fungi

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42
Q

True or false: Natural Killer cells secrete fas ligand killing to induce apoptosis

A

True

43
Q

Where are mast cells found?

A

In tissues

44
Q

What is the role of mast cells

A

Inflammation, release cytokines, increased vascular permeability, promotes recruitment and activation of immune cells, parasitic infections through IgE/IgG binding and FC receptor cross linking

45
Q

Where are Basophils/Eosinophils found?

A

Blood (low proportion of WBC)

46
Q

What do Basophils/Eosinophils release?

A

Histamine and cytokines

47
Q

What is Inflammation?

A

Recruitment of leukocytes and plasma proteins from the blood which accumulates in tissues. Activation of mediators occurs to destroy microbes/wound
repair

48
Q

Signs of inflammation

A

Dolor (pain), Calor (heat), Rubor (redness), Tumor (swelling), Functio laesa (loss of function)

49
Q

Causes of inflammation characteristics

A

Vasodilation/ Increased blood flow (heat, redness), Fluid accumulation (swelling), Chemical activation /cytokine release (ie histamine, bradykinin) that stimulates nerve endings (pain, loss of function)

50
Q

The purpose of inflammation

A

Eliminate the initial cause of cell injury (infection), clear out necrotic cells and tissues, initiate tissue repair.

51
Q

Process of Inflammation

A
  1. Mast cells initiate this process
  2. Macrophages/neutrophils, and dendritic cells to release inflammatory mediators
  3. Mediators cause inflammation signs to allow for increased permeability to allow cells to cross
  4. Immune cells are activated
52
Q

True or False: IL-1 and IL-6 are not produced by endothelial and epithelial cells

A

False, they are produced by endothelial and epithelial cells

53
Q

What happens if there are any disturbances in the tissue repair process

A

Aberrant repair

54
Q

Outcome of Inflammation

A

Resolution, Repair, Areas of destruction replaced by scar tissue, Mediators intensify the inflammatory process, Mediators generate more mediators

55
Q

Mast cells

A

Specialized connective tissue cells with granules filled with histamine, a vasodilator (promotes the dilatation of blood); initiate the process of inflammation

56
Q

What are the chemical mediators of Inflammation?

A

Mast cells, Histamine, serotonin, prostaglandins, leukotrienes

57
Q

Chemical Mediators of Inflammation from blood plasma

A

Bradykinin and Complement

58
Q

What is Complement

A

Series of proteins that interact in a regular sequence. They are activated by antigen-antibody reactions

59
Q

Exudate

A

A mass of cells and fluid that has seeped out of blood vessels or an organ (important in inflammation)

60
Q

What is in the fluid mixture of Exudate

A

Proteins, leukocytes and tissue debris

61
Q

Serous exudate

A

Primarily fluid, little protein

62
Q

Purulent exudate

A

Largely inflammatory cells (pus)

63
Q

Fibrinous exudate

A

Rich in fibrinogen; coagulates and forms fibrin; produces a sticky film on surface of inflamed tissue

64
Q

Adhesions exudate

A

Bands of fibrous tissue that bind adjacent tissue together

65
Q

Hemorrhagic exudate

A

Increased red blood cells

66
Q

How do immune cells communicate?

A

Cytokines

67
Q

True or False: one cytokine influences the synthesis of other cytokines

A

True, produces a cascade

68
Q

Cells that respond to cytokine

A

Autocrine (same cell), paracrine (nearby cell), or endocrine (distant cell)

69
Q

Monokines

A

Cytokines produced by mononuclear phagocytic cells

70
Q

Lymphokines

A

Cytokines produced by activated lymphocytes, especially Th cells

71
Q

Interleukins

A

Cytokines that act as mediators between leukocytes

72
Q

Chemokines

A

Type of cytokine that help in the host immune response and the movement of leukocytes and other cells

73
Q

TNF-α

A

Induced by LPS; It is an important mediator of acute inflammation. It mediates the recruitment of neutrophils and macrophages to sites of infection

74
Q

IL-1

A

inflammatory cytokine produced by activated macrophages.
(Similar to TNF-α; Helps activate T-cells)

75
Q

IL-10

A

Interleukin 10 is produced by activated macrophages and Th2 cells (CD4); Inhibitory cytokine

76
Q

What does IL-10 Inhibit?

A

inhibits production of IFN-γ by T cells, which shifts immune responses from attack to repair functions and cytokine production by activated macrophages and the expression of class 2 MHC

77
Q

IL-12

A

Produced by activated macrophages and dendritic cells and stimulates the production of IFN-γ and induces the differentiation of Th cells to become Th1 cells

78
Q

Type I interferons

A

Type I interferons (IFN-α and IFN-β) are produced by many cell types and they
function to inhibit viral replication in cells.

79
Q

Pathogen Associated Molecular Patterns (PAMPs)

A

Activate Innate Immune Response; cell associated receptors mediated through toll-like receptors

80
Q

Lipopolysaccharide

A

gram –ve bacteria cell membranes

81
Q

Lipoteichoic acid

A

gram +ve bacteria

82
Q

ds RNA

A

Virus

83
Q

unmethylated CpG DNA sequences

A

Bacteria

84
Q

Damage associated molecular patterns (DAMPs)

A

Tend to be nuclear/cytosolic proteins; Trigger inflammatory response in macrophages/neutoriphils/dendritic cells

85
Q

PRR (Pattern Recognition Receptors)

A

TLR-Toll like receptor, RLR-Rig like receptor (IFNα/β), NLR-NOD like receptor (inflammatory), Lectin like receptors

86
Q

Toll Like Receptors (TLR)

A

Bind/ react to a wide range of microbial targets not present in/on healthy cells

87
Q

Which transcription factors does TLR signalling activate

A

IRFs and NF-kB

88
Q

IRF (Interferon regulator Factors)

A

IFN α, IFN β

89
Q

NF-κβ

A

TNFα (Tumor Necrosis Factor), IL-1, IL-6, Adhesion molecules

90
Q

DAMP vs PAMP

A

intra/extra will activate different pathways to produce different cytokine profiles that will polarize Macrophages more suited to Killing (infection) or repair (healing), or both

91
Q

The Complement System

A

Composed of 30+ proteins found in the blood; Synthesized by hepatocytes in the liver

92
Q

Basic functions of complement

A

Opsonization (enhancing phagocytosis of antigens), Chemotaxis (activating macrophages and neutrophils) , Cell Lysis (rupturing membranes of foreign cells), Agglutination (binding pathogens)

93
Q

What can complement proteins be activated by?

A

A cut, can work in milliseconds to start clotting; antigen antibody reaction

94
Q

Membrane Attack Complex (MAC)

A

This compromises the integrity and in turn causes the destruction of the target bacterium

95
Q

True or False: Innate Immunity has more effectiveness against intracellular pathogens vs. extracellular pathogens

A

False, has more effectiveness against extracellular pathogens (Intra = adaptive)

96
Q

Type 1 Interferons

A

Secreted by cells in response to PAMP recognition; Most potent stimuli for type I interferon synthesis are viral nucleic acids

97
Q

Types of Type 1 Interferons

A

Interferon α (mostly dendritic cells, macrophages) and
Interferon β (a wide range of cells)

98
Q

Roles of Type 1 Interferons

A

Increase cytotoxicity of the “killers”, Upregulate expression of class I MHC molecules, Cause sequestration (keep producing them) of lymphocytes in lymph nodes, Improved resistance to infection (infected and uninfected cells)

99
Q

Paracrine action

A

Virally infected cells secretes type I interferons to act and protect adjacent cells not yet infected

100
Q

What do the cells of the Innate Immunity promote?

A

Differentiation, proliferation or T and B cells

101
Q

Dendritic cells

A

Professional Antigen Presenting Cells (APC) located at common sites of entry of microbes (skin, mucosa, organ parenchyma)

102
Q

Which cells do dendritic cells present antigens to?

A

After antigens have been captured and sent to the lymph nodes they are presented to T lymphocytes

103
Q

X-presentation

A

Infected cells/debris engulfed, digested and presented