Immune 1 Flashcards

1
Q

What is immunity?

A

protection against infections

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2
Q

What is the immune system?

A

collection of cells and molecules that are responsible for defending the body against pathogens

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3
Q

What is a pathogen?

A

organism that causes disease

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4
Q

What is the goal of the immune system?

A
  • Prevent foreign substances from entering the body
  • Establish immunocompetence: ability of the body to produce a robust immune response following exposure to disease-producing agents
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5
Q

What are the characteristics of innate immunity?

A
  • Mediates initial protection against infections
  • Nonspecific defense
  • Rapidly eliminate microbes that enter host tissues
  • Eliminate damaged and necrotic cells
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6
Q

What are the different types of nonspecific defenses for the innate immunity?

A
  • Physical barriers: skin, mucus membrane, nasal hairs, respiratory tract cilia
  • Chemical barriers: skin pH, mucous secretions, gastric acids, tears, sweat, saliva
  • Effector cells: macrophages, neutrophils, NK cells
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7
Q

What are the main cells of the innate immune system?

A

macrophages, neutrophils, NK cells, dendritic cells

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8
Q

What are the main ways that the epithelium acts as part of innate immunity?

A
  • physical barrier to infection
  • killing of microbes by locally produced antibiotics
  • killing of microbes and infected cells by intraepithelial lymphocytes
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9
Q

What are pathogen associated molecular patterns (PAMPS)?

A

Recognize general microbial pattens through pattern recognition receptors

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10
Q

What part of the immune system has PAMPS and DAMPS?

A

innate

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11
Q

What are damage associated molecular patters (DAMPS)?

A

Recognize molecules released from damaged or necrotic host cells

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12
Q

What is the first cell type to respond to most infections (bacterial and fungal)?

A

neutrophils

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13
Q

What type of cell usually activates neutrophils?

A

macrophage

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14
Q

What are the features of neutrophils?

A
  • Short-lived
  • Ingest and degrade dead cells, debris, tumor cells, pathogens, foreign material through phagocytosis
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15
Q
A

Neutrophil

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16
Q

What are the features of dendritic cells?

A
  • Thin, membranous cytoplasmic processes
  • Present antigens to T cells
  • Abundant near epithelium, mucus membranes
  • Help shape adaptive immune response
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17
Q

What is the job of a dendritic cell?

A
  • Present antigens to T cells
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18
Q
A

dendritic cells

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19
Q

What are the features of a macrophage?

A
  • Survive in extravascular tissue for long periods
  • Ingest and degrade dead cells, debris, tumor cells, pathogens, foreign material through phagocytosis
  • May present antigens to T cells
  • Release cytokines to activate other immune cells
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20
Q

What is the lifespan of a macrophage?

A
  • Survive in extravascular tissue for long periods
    (months or years)
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21
Q

What is the lifespan of a neutrophil?

A

short-lived

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22
Q

What are the types of professional antigen presenting cells?

A
  • dendritic cells
  • macrophages
  • B cells
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23
Q

What are the features of the natural killers cells?

A
  • Capable of rapidly attacking and killing infected cells
  • Induce cell apoptosis
  • Release cytokines to activate other immune cells
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24
Q

How can a natural killer do its job?

A
  • directly kill an infected cell (especially virus)
  • stimulate a macrophage with phagocytosed microbes to kill itself
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25
Q

What is the complement system?

A

Collection of circulating and membrane-associated proteins important in the defense against microbes

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26
Q

What is the classical pathway?

A

activated by antibodies that bind to microbes or other antigens → component of adaptive immunity (humoral)

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27
Q

What is the alternate pathway?

A

activated when complement proteins are activated on microbial surfaces → component of innate immunity

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28
Q

What is the lectin pathway?

A

activated by mannose binding lectin binds to surface glycoproteins on microbes → component of innate immunity

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29
Q

What is the lectin pathway activated by?

A

mannose binding lectin binding to surface glycoproteins on microbes

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30
Q

What is the alternate pathway activated by?

A

complement proteins are activated on microbial surfaces

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31
Q

What is the classical pathway activated by?

A

antibodies that bind to microbes or other antigens

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32
Q

What two complement pathways are innate immunity?

A

alternate pathway
lectin pathway

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33
Q

What complement pathway is adaptive immunity (humoral)?

A

classical

34
Q

All three complement pathways lead to form the…

A

membrane attack complex (MAC)

35
Q

What does formation of the membrane attack complex (MAC) in complement lead to?

A

lysis of microbe

36
Q

What are the functions of the complement system?

A
  • Opsonization and phagocytosis
  • Inflammation
  • Cell lysis
37
Q

What does opsonization and phagocytosis do in the complement system?

A

C3b coats microbes, promotes binding to phagocytes → microbes ingested and destroyed

38
Q

What does inflammation do in the complement system?

A

C5a and C3b are chemoattractants for leukocytes → recruit and promote inflammation

39
Q

What does cell lysis do in the complement system?

A

complement activation concludes with the MAC → microbial death

40
Q

What are cytokines?

A

soluble proteins that mediate immune and inflammatory reactions (communication)

41
Q

What are the functions of cytokines?

A
  • Responsible for communication b/w leukocytes and other cells
  • Most cytokines function in autocrine and paracrine actions
42
Q

How are cytokines released?

A
  • Secreted in small amounts in response to external stimuli
43
Q

What cell makes IL-12 and what cells does it affect?

A
  • released by dendritic and macrophages
  • affects NK and T cells
44
Q

What cell makes IFN-y and what cells does it affect?

A
  • release by NK and T cells
  • activates macrophages
45
Q

What cell makes TNF and what does it affect?

A
  • released by macrophages, T cells, mast cells
  • activates endothelial cells, neutrophils, and leads to inflammation
46
Q

What cells make IL-1 and what does it affect?

A
  • released by macrophages, dendritic cells, endothelial cells, epithelial cells, and mast cells
  • activates endothelial cells and leads to inflammation
47
Q

What cells make chemokines and what does it affect?

A
  • released by macrophages, dendritic cells, endothelial cells, T cells, fibroblasts, and platelets
  • affects leukocytes
48
Q
A
49
Q

What innate immune response do you get from extracellular bacteria and fungi?

A

acute inflammatory response and complement

50
Q

What innate immune response do you get from intracellular bacteria?

A

eliminated by phagocytes

51
Q

What innate immune response do you get from viruses?

A

Type I interferon, NK cells

52
Q

What are the types of receptors of innate immunity?

A
  • Toll-like receptor
  • Nod-like receptor
  • C-type lectin receptor
53
Q

What is a toll-like receptor?

A

plasma membrane and endosomal receptors
* Recognize lipopolysaccharide (LPS), viral and bacterial RNA/DNA

54
Q

What is a nod-like receptor?

A

cytosolic receptors
* Recognize necrotic cell products, ion disturbances, microbial products

55
Q

What is a C-type lectin receptor

A

plasma membrane
* Recognize fungal polysaccharides

56
Q

Where are toll-like receptors located in the cell?

A

plasma membrane and endosomal receptor

57
Q

Where are NOD-like receptors located in the cell?

A

cytosol

58
Q

Where are C-type lectin receptors located in the cell?

A

plasma membrane

59
Q

What are the primary lymphoid organs?

A

bone marrow and thymus

60
Q

Where do B cells develop?

A

bone marrow

61
Q

Where do T cells develop?

A

thymus

62
Q

What are secondary lympoid organs?

A
  • Sites where adaptive immunity is initiated
  • Lymphocytes have contact with antigens
63
Q

What role does bone marrow have in immune system?

A
  • Produces the cells of the immune system from stem cell precursors
  • Soft, spongy tissue in the medullary cavity of bones
64
Q

What role does the thymus have in immune system?

A
  • Lymphatic organ responsible for the maturation and specialization of white blood cells called T lymphocytes
  • After maturation, T lymphocytes enter bloodstream and travel to secondary lymphatic sites
65
Q

What is waldeyer’s ring?

A
66
Q
A
67
Q

Where are most lymphocytes found?

A

lymph nodes

68
Q

What is the difference between innate and adapative immunity?

A
  • Innate immunity: first line of defense
  • Develops quickly
  • Rapidly reacts against infectious pathogens
  • No memory
  • Adaptive immunity: specialized immunity
  • Develops more slowly
  • Mediates an effective defense against infections
  • Memory for future encounters
69
Q

What are the main effector cells of the adaptive immunity?

A

B and T cells

70
Q

What is the function of the adaptive immune system?

A
  • Recognizes diverse foreign substances
  • Triggered when microbes pass through epithelial barriers, recognized by lymphocytes in lymphoid organs
71
Q

What is an antigen?

A

substance that can induce an immune response

72
Q

What are the two parts of the adaptive immune system?

A
  • humoral immunity
  • cell-mediated immunity
73
Q

What is humoral immunity mediated by?

A

antibodies produced by B lymphocytes

74
Q

What is cell-mediated immunity mediated by?

A

T lymphocytes

75
Q

Where are B and T cells in the lymph node?

A

T cells - parafollicular region
B cells - follicular region

76
Q

What are the functions of antibodies?

A
  • Secreted into circulation and mucosal fluids
  • Neutralize and eliminate microbes and microbial
    toxins
  • Prevent infections from being established
77
Q

What cell makes antibodies?

A

B cells

78
Q

B cells make up what percent of circulating peripheral lymphocytes?

A

10-20%

79
Q

What do B cells do?

A
  • Recognize antigens through membrane bound IgM
  • Recognize many chemical structures: soluble or cell-associated proteins, lipids, polysaccharides, nucleic acids, small chemicals
  • Differentiate into plasma cells after stimulation: secrete antibodies
80
Q

Where are B cells activated?

A

peripheral lymphoid organs

81
Q
A