(Section B: Immunology) Lecture 10: Innate Immunity I Flashcards

1
Q

True or False:

Innate Immunity and Adaptive Immunity are separate systems

A

False, they are intertwined different types of responses of the immune system

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2
Q

Which type of immune response came first?

A

Innate immunity came first

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3
Q

For Adaptive and Innate Immunity, compare:

Source

A

Innate
* Germ line encoded genes

Adaptive
* Recombination of genes
* Very rapid changes

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4
Q

For Adaptive and Innate Immunity, compare:

Inheritance

A

Innate
* Inherited

Adaptive
* Non-inherited

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5
Q

For Adaptive and Innate Immunity, compare:

Specificity

A

Innate
* Recognizes evolutionarily conserved molecular patterns

Adaptive
* Recognizes dynamically changing molecular patterns

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6
Q

For Adaptive and Innate Immunity, compare:

Memory

A

Innate
* Epigentic imprinting of past pathogen encounters

Adaptive
* Survival of clone cells expressing specific receptors to past antigens

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7
Q

For Adaptive and Innate Immunity, compare:

Structure

A

Innate
* Physical barriers
* Chemical defenses
* Cellular responses

Adaptive
* Cellular responses
* Antibody production

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8
Q

For Adaptive and Innate Immunity, compare:

Dynamics

A

Innate:
* Present in individuals at all times

Adaptive:
* Formed as antigens are encountered

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9
Q

What are the 6 ways that innate and adaptive immunity differ?

A
  1. Source
  2. Inheritance
  3. Specificity
  4. Memory
  5. Structure
  6. Dynamics
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10
Q

What aspects of the immune system are there?

A
  1. Innate
  2. Adaptive
  3. Cellular
  4. Humoral
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11
Q

Cellular Immunity

A

Cell-based immunity
* Cells recognize another cell to destroy
* Mediated by living cells

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12
Q

Humoral Immunity

A

Refers to liquids (humors)
* Molecules that are soluble in liquids of the body (blood, plasma, saliva, tears etc.)
* Involves antibodies

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13
Q

Which 2 scientists are considered the founders of immunology?

A

Ehrlich and Metchnikoff

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14
Q

What is Metchnikoff known for?

A
  • Embryologist
  • Cellular and Innate Immunity
  • Phagocytosis
  • Macrophages
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15
Q

What is Ehrlich known for?

A
  • Chemist
  • Humoral and Adaptive Immunity
  • Antibodies
  • Side chain theory
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16
Q

Explain blood composition

A
  • 55% plasma (blood hormones, clotting factors, antibodies, proteins, enzymes etc.)

The rest is comprised of cells
* ~1% buffer coat (leukocytes, WBCs, platelets)
* 45% erythrocytes (RBCs)

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17
Q

Hematopoesis

A

Blood Cell Formation

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18
Q

How does hematopoesis work?

A
  1. Hematopoetic stem cells (self renewing)
  2. Differentiates into myeloid progenitor and lymphoid progenitor
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19
Q

What cells are of myeloid origin?

A
  • Neutrophils
  • Monocytes/Macrophages
  • Dendritic cells
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20
Q

What cells are of lymphoid origin?

A
  • B cells
  • T cells
  • Innate lymphoid cells
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21
Q

Cells of the Immune System:

Lymphocytes

A

Split into:
* T cells
* B cells
* Innate lymphoid cells (ILCs)

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22
Q

What aspect of the immune system do T cells belong to?

A

Cellular adaptive immunity

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23
Q

What aspect of the immune system do B cells belong to?

A

Humoral adaptive immunity

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24
Q

Give an example of an innate lymphoid cell

A

NK (Natural Killer) Cells

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25
Q

What are characteristics of lymphocytes?

A
  • Small cytoplasm
  • Large nucleus
  • Small cell size

ILCs have small granules

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26
Q

Cells of the Immune System:

Mast Cells

A

“Well fed”
* Stuffed with granules, seen in staining

27
Q

What do granules in mast cells produce?

A

Produce and release histamine

28
Q

Where are mast cells found?

A

Epithelial barrier tissues

29
Q

What do histamines do?

A

Signals to open up blood flow

30
Q

Where are examples of locations that mast cells would be found?

A
  • Lung
  • Digestive tissues
  • Skin
31
Q

Cells of the Immune System:

Eosinophils and Basophils

A

Eosinophils
* “Dye loving”
* Granules stain pink

Basophils
* “Base loving” - loves basic dyes
* Granules stain blue

32
Q

What do basophils contain?

A

Glycogen

33
Q

What roles do eosinophils and basophils play in the immune system?

A

Play roles in allergies and parasitic reactions

34
Q

Cells of the Immune System:

Neutrophils

A

“Neutral pH”

35
Q

What is the structure of neutrophils?

A

Has segmented nucleus
* Helps them squeeze through tight spaces to reach injury

Contains granules

36
Q

What is the lifespan of neutrophils?

A

Short lifespan: A few days

37
Q

Macrophages vs. Microphages

A

Macrophages - “Big eaters”
Microphages - “Small eaters”

38
Q

What percentage of cells do neutrophils make up?

A

A majority of the WBCs
* 50-70% of blood circulating leukocytes

39
Q

What do dead neutrophils appear as?

A

Dead neutrophils appear as pus (yellowish substance at sites of infections)

40
Q

What is the mechanism of neutrophils?

A
  • Signalled to exit bloodstream by injury
  • Large numbers swarm injury sites
41
Q

What process can neutrophils undergo?

A
  • Phagocytosis
  • Netosis
42
Q

Describe the process of netosis

A
  1. Stimuli sends activation signal to neutrophil
  2. Neutrophil “throws out” or expels chromatin nets
  3. Nets ensnare extracellular pathogens
43
Q

What are the chromatin nets like in netosis?

A

Decorated with antimicrobial proteins
* More than 20 different proteins including antimicrobial peptides, MPO, elastase

44
Q

Cells of the Immune System:

Dendritic Cells

A

“Branching cells”

45
Q

What are the branches of a dendritic cell known as?

A

Processes or Pseudopodia

46
Q

What is the structure of dendritic cells?

A

Contains lysosomes and phagosomes
* Lysosomes are acidic

47
Q

Where are dendritic cells present?

A

In the tissues

48
Q

What are the dendritic cells commonly known as?

A

Professional phagocytes
* Just eats cells all the time

49
Q

Cells of the Immune System:

Monocytes

A
  • Present in the blood
  • Can differentiate into macrophages
50
Q

Cells of the Immune System:

Macrophages

A

“Big eater”

51
Q

Where are macrophages present?

A

In various tissues of the body

52
Q

What roles do macrophages play?

A
  • Highly phagocytic
  • Removes pathogens and body cells
  • Involved in tissue remodeling (ex. removing webbing between fingers)
53
Q

Are monocytes phagocytic?

A

Yes

54
Q

Do macrophages have different functions?

A

Yes, they have specialized functions depending on which tissue they live in

55
Q

What is the lifespan of a macrophage?

A

Long lifespan
* Months to years

56
Q

What are the steps to phagocytosis? (5)

A
  1. Bacterium binds to PRRs on membrane evaginations called pseudopodia (processes, dendrites)
  2. Bacterium is ingested forming phagosome
  3. Phagosome fuses with lysosome
  4. Bacterium is killed and then digested by low pH-activated lysosomal enzymes
  5. Digestion products are released from cell
57
Q

Phagocytosis:

What are phagosomes essentially?

A

Vacuoles that engulf bacterium

58
Q

Phagocytosis:

Describe the environment of a lysosome

A
  • Low pH (4.5)
  • Enzymes activated to digest material
59
Q

Phagocytosis:

Where does the digestion products go?

A
  • Disposed
  • Can be given to immune system to start immune response
  • Can be recycled
60
Q

List:

Phagolysosome antimicrobial properties

A
  1. Low pH
  2. NADPH oxidase: Reactive oxygen species that kills
  3. Myeloperoxidase (MPO): Transforms hydrogen peroxide into hypochlorous acid (bleach)
  4. Lactoferrin: Captures Fe2+ that is essential for bacterial growth
  5. Defensins: Punches pores into the bacteria
  6. Lysozyme: Degrades peptidoglycan
61
Q

What happens to bacteria that survive phagocytosis?

A

Can live/replicate inside a phagocyte
* In the phagosome, phagolysosome, or escape to neighboring cells

62
Q

What are methods that bacteria can survive phagocytosis with?

A
  • Inhibition of phagosome-lysosome fusion
  • Survival mechanisms to the inside of the phagolysosome
  • Degradation of phagolysosome (to escape into cytoplasm and reproduce)
63
Q

What bacteria are professional intracellular pathogens?

A
  • Salmonella
  • Mycobacterium
  • Listeria monocytogenes
  • Staphyloccocus aureus