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BIOL71040 > Week 3: Basics of Immunology > Flashcards

Week 3: Basics of Immunology Flashcards

1
Q

T or F: Our immune system get weaker as we age?

A

TRUE

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2
Q

T or F: Vaccines overload the immune system

A

FALSE

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3
Q

T or F: Antibiotics help treat Influenza (the flu)?

A

FALSE

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4
Q

What are the two broad types of immunity?

A

Innate and Adaptive Immunity

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5
Q

What are 3 examples of the innate and adaptive immune systems interacting?

A

Dendritic Cells
Macrophages
Complement system

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6
Q

What do Dendritic Cells do between the innate and adaptive immune systems?

A

Capture and process antigens from pathogens, then present them to T cells which activates them to target the specific pathogen.

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7
Q

What do Macrophages do between the innate and adaptive immune systems?

A

Engulf pathogens and present their antigens on their surface; helps to activate T cells to then proliferate and differentiate to eliminate the specific pathogen.

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8
Q

What does the Complement System do between the innate and adaptive immune systems?

A

Can be activated by antibodies from the AIS, which enhances the ability of the immune system to clear pathogens through opsonization (marking pathogens for destruction) and lysis of the pathogen’s cell membrane.

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9
Q

What are the 3 components of the Innate Immune system?

A

Physical barriers
Chemical Defenses
Cellular Defenses

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10
Q

What are 2 examples of Physical Barriers?

A

Skin, Mucous Membrane

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11
Q

What are 2 types of Chemical Defenses?

A

Endogenous mediators
Exogenous mediators

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12
Q

What are Endogenous mediators?

A

Substances created by the body’s own cells to combat microbial invaders.

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13
Q

What is an example of a Endogenous Mediator?

A

Gastric fluid (highly acidic environment in the stomach kills most ingested microbes),

Histamine (released by mast cels to mediate inflammatory responses).

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14
Q

What are Exogenous Mediators?

A

Substances produced by microbes within our microbiome to inhibit other microbes

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15
Q

What is an example of an Exogenous Mediator?

A

Lactate (produced by lactobacilli in the vagina by fermenting glycogen, lowers pH and inhibits pathogen),

Bacteriocins (produced by resident gut microbiota, disrupt the membranes of competing bacteria).

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16
Q

What are Cellular Defenses?

A

Phagocytes

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17
Q

Name 3 types of Phagocytes

A

Basophils,
Eosinophils,
Neutrophils

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18
Q

How do Phagocytes destroy pathogens?

A

Phagocytosis

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19
Q

What are the 6 steps of Phagocytosis?

A

Chemotaxis
Pathogen Recognition
Engulfment
Phagolysosome Formation
Destruction and Digestion
Exocytosis

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20
Q

What is Step 1: Chemotaxis of Phagocytosis?

A

Phagocytes are recruited to the site of infection by chemical signals (chemoattractant).

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21
Q

What is Step 2: Pathogen Recognition of Phagocytosis?

A

Phagocytes recognize pathogens through molecules on their surface called Pathogen Associated Molecular Patters (PAMPs).

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22
Q

What is Step 3: Engulfment of Phagocytosis?

A

Phagocyte extends its membrane around the pathogen forming pseudopods that engulfs the pathogen; encloses the pathogen inside a phagosome inside the phagocyte.

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23
Q

What is Step 4: Phagolysosome Formation of Phagocytosis?

A

The phagocyte containing the pathogen fuses with a lysosome, an organelle containing digestive enzymes, to form a phagolysosome which enhances the acidic environment, critical for activating enzymes that digest the pathogen.

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24
Q

What is Step 5: Destruction and Digestion of Phagocytosis?

A

The pathogen is broken down by various enzymes (lysozyme, phospholipases, and proteases) and reactive oxygen + nitrogen contribute to the destruction of the pathogen to effectively neutralize the threat posed by the pathogen.

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25
What is Step 6: Exocytosis of Phagocytosis?
The phagocyte expels the indigestible waste from the pathogen in small vesicles through the cell membrane of the phagocyte to release the contents outside the cell; some parts are retained and presented on the cell’s surface to help activate the adoptive immune response.
26
What triggers Inflammation?
Begins when cells are damaged or stressed, or when pathogens breach the body’s defenses; this triggers a series of chemical signals and cellular responses that initiate inflammation.
27
What are the Key Signs of Inflammation? (SHARP)
Swelling Heat Altered Function Redness Pain
28
What are the 3 components of the Adaptive Immune System?
Specificity Memory Tolerance
29
Adaptive Immune System: What is Specificity?
The ability to target specific pathogens
30
Adaptive Immune System: What is Memory?
The ability to remember past infections and respond more rapidly and effectively to subsequent exposures to the same pathogen
31
Adaptive Immune System: What is Tolerance?
The ability of the immune system to differentiate between itself and non-self
32
What are the 2 categories that the Adaptive Immune System is divided into?
Cell-mediated Immunity Humoral Immunity
33
What are the 3 cell-types found in the Cell-mediated immune system?
Cytotoxic T cells Helper T cells Regulatory T cells
34
What are Cytotoxic T cells?
They destroy cells infected with viruses, cancer cells, and other foreign cells.
35
What are Helper T cells?
They are a type of white blood cell that help activate other immune cells to fight infections.
36
What are Regulatory T cells?
White blood cells that regulate the immune system.
37
What is T cell Activation?
A complex interaction of molecular signals and cellular responses that trigger the immune system
38
T Cell Activation: What do T cell Receptors (TCRs) recognize?
Specific foreign epitope
39
T Cell Activation: What are examples of Antigen-Presenting Cells (APCs)?
Macrophages Dendritic Cells B Cells
40
T Cell Activation: What is the role of Macrophages and Dendritic Cell in T Cell Activation?
The phagocytes ingest and destroy pathogens that breach physical barriers like skin and mucous membranes. They recognize pathogens through nonspecific interactions (e.g., PAMPs and toll-like receptors).
41
T Cell Activation: What is the role of B Cells in T Cell Activation?
B cells are not phagocytes. Instead, they specialize in producing and secreting antibodies. B cells use antigen-specific immunoglobulin receptors (IgD and IgM) to bind to antigens, which they then internalize and present to T cells after processing.
42
T Cell Activation: What type of T cell is MHC I associated with?
Present on all nucleated cells, these molecules display both normal self-antigens and abnormal/non-self antigens to effector T cells, playing a crucial role in cellular immunity.
43
What type of T cell is MHC II associated with?
Found only on specialized cells like macrophages, dendritic cells, and B cells, MHC II molecules present non-self antigens to T cells, initiating the immune response.
44
T Cell Differentiation: What is the role of Effector T cells?
Effector T cells are specialized immune cells that actively carry out the immune response by directly attacking and eliminating infected cells, bacteria, or tumor fragments once they encounter a specific antigen, essentially acting as the "executioners" of the immune system to clear infections and threats. They are the functional end result of a T cell becoming activated and differentiating to perform a specific immune function.
45
T Cell Differentiation: How do Memory T cells contribute to immunity?
By "remembering" past infections, allowing for a faster and stronger immune response if the body encounters the same pathogen again.
46
T Cell Differentiation: What is the primary goal of cell-mediated immunity?
The primary goal of cell-mediated immunity is to destroy infected cells, particularly those harboring intracellular pathogens like viruses, by directly targeting and killing them through the action of cytotoxic T cells, thereby preventing further spread of the infection within the body.
47
T Cell Differentiation: How does cell-mediated immunity protect against intracellular pathogens?
It directly kill infected host cells displaying pathogen antigens on their surface, effectively eliminating the pathogen hiding inside the cell, a process that cannot be achieved by antibodies alone which target extracellular pathogens
48
What is Humoral Immunity?
Humoral immunity is a defense mechanism that uses antibodies to protect the body from infection.
49
What is an Antigen?
An antigen is a substance that triggers the body's immune system to produce antibodies.
50
Where can Antigens be found?
Antigens can be found on the surface of cells, in body fluids, or in the environment.
51
How are antibodies made?
1. When an antigen enters the body, it binds to a B cell. 2. The B cell divides and clones itself, creating plasma cells. 3. The plasma cells release antibodies into the bloodstream and lymph system. 4. Antibodies bind to antigens, marking them for removal from the body.
52
What are the 5 roles of Antibodies?
1. Neutralization 2. Opsonization 3. Agglutination 4. Complement activation 5. Antibody-dependent cell-mediated cytoxicity
53
What is the role of Neutralization in Antibodies?
Blocks the harmful effects of bacterial toxins, viruses, and other pathogens by preventing their attachment to host cells.
54
What is the role of Opsonization in Antibodies?
Involves the coating of pathogens with molecules (e.g. complement factors, CRP, serum amyloid) to enhance their recognition and ingestion by phagocytes, such as macrophages, dendritic cells, and neutrophils.
55
What is the role of Agglutination in Antibodies?
Involves the cross-liking of pathogens with antibodies to create large aggregates.
56
What is the role of Complement Activation in Antibodies?
The triggering of a cascade of protein reactions that promotes opsonization, inflammation, phagocyte recruitment, and the direct destruction of pathogens (E.g. membrane attack complex).
57
What is the role of Antibody-dependent Cell-mediated Cytotoxicity in Antibodies?
Facilitates the destruction of large pathogens by binding antibodies to the pathogen and attracting effector cells like NK cells, which then release cytotoxins to kill the pathogen.
58
B Cell Development: Where do B cells mature?
B cells mature in the bone marrow and spleen.
59
B Cell Development: What is the function of the B cell receptor (BCR)?
It recognizes and binds to specific antigens, initiating the activation of the B cell, leading to the production of antibodies against that specific antigen.
60
B Cell Activation: What happens when a B cell's receptor binds to an antigen?
Elicits a response that eventually leads to production of antibodies.
61
B Cell Activation: After binding to an antigen, B cells interact with which type of T cell?
Helper T cells
62
B Cell Activation: What is the role of Helper T cells in B cell activation?
Helper T cells play a crucial role in B cell activation by providing necessary signals, through the release of cytokines, that stimulate B cells to proliferate and differentiate into antibody-producing plasma cells, essentially acting as the "command center" to orchestrate the humoral immune response by guiding B cell activity and antibody production against specific antigens.
63
B Cell Differentiation: What is the main function of plasma cells?
To produce and secrete antibodies
64
B Cell Differentiation: How do memory B cells contribute to long-term immunity?
By "remembering" a specific pathogen, allowing for a rapid and robust antibody production upon re-exposure to that pathogen, effectively preventing or significantly reducing the severity of a secondary infection.
65
What do IgG antibodies do?
Most abundant (~80% of total serum antibody) and versatile antibody in the blood and essential for fighting bacterial and viral infections; can cross the placental barrier.
66
What do IgA antibodies do?
Found in the mucous membranes, breast milk, tears, saliva, and accounts for ~13% of total serum antibody; works to protect body surfaces that are exposed to foreign substances, such as trapping pathogens in mucous so they can be destroyed later.
67
What do IgM antibodies do?
The first antibody produced in response to an infection (primary and secondary immune responses); is capable of forming pentamers.
68
What do IgF antibodies do?
Involved in allergic reactions and defense against parasitic infections; the least abundant antibody.
69
What do IgD antibodies do?
Functions mainly as a receptor on B cells that have not been exposed to antigens.
70
What are cytokines?
They are soluble proteins that serve as communication signals between cells in the immune system. They can trigger various responses like cell proliferation, differentiation, inhibition of division, apoptosis, and chemotaxis, depending on the type of cytokine and its target receptor.
71
What are the 3 classes of cytokines?
Interleukins Chemokines Interferons
72
What are Interleukins?
Modulate immune responses and stimulate various cell types
73
What are Chemokines?
Recruit specific leukocytes to infection or injury sites
74
What are Interferons?
Vital in viral defense, especially in inhibiting viral replication and activating immune cells.
75
What are the 3 functions of Cytokines?
Autocrine Paracrine Endocrine
76
What are Autocrine Cytokines?
The cytokine affects the cell that produced it
77
What are Paracrine Cytokines?
The cytokine acts on nearby cells
78
What are Endocrine Cytokines?
The cytokine travels through the bloodstream to distant cells.
79
What are the 4 main events of Acute Inflammation?
1. Tissue damage 2. Release of inflammation mediators 3. Vasodilation 4. Removal of invading microbes
80
What is Sepsis?
This occurs when the body's response to infection triggers widespread inflammation, leading to tissue damage, organ failure, and potentially death if not treated promptly.
81
What is Cytokine Storm?
An overactive immune response where excessive inflammation causes severe tissue damage, often seen in severe viral infections like COVID-19
82
What is Anaphylaxis?
A severe allergic reaction where inflammation leads to airway constriction, low blood pressure, and shock, which can be fatal without immediate treatment.
83
What are Free Antigens?
Free-floating in the environment and only B cells respond to them
84
What are Presented Antigens?
Presented by immune cells called antigen presenting cells (APCs) and only T cells respond to them
85
What is T cell Dependent Activation?
Helper T cells recognize the antigen (typically proteins) presented by B cells and provide signals (cytokines) that activate the B cells (more common)
86
What is B cell Activation by T Independent Antigens?
T cells are not required to activate a B cell. Instead, antigens such as carbohydrates or lipids can independently activate a B cell (less common)

BIOL71040 (12 decks)

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