Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Principles > Immunology > Flashcards

Immunology Flashcards

1
Q

When would immunosuppression be utilitised?

A

Patients may be artificially immunosuppressed in the event of an autoimmune disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the properties of the skin as a physical barrier to infection

A

It is constantly renewed

It has a low pH

It has low oxygen tension

Sebaceous glands secrete hydrophobic oild whick make it hard for pathogens to bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mucous line all _____ ________ that come into contact with the ___________

A

Body cavities

Environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mucous contains many constitutes which can fight potential pathogens, what are these?

A
  • Secretory IgA
  • Lysozymes
  • Defensins
  • Antimicrobial peptides
  • Lactoferrin - starve invading bacteria of iron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are commensal bacteria?

A

Bacteria that reside in the body and on epithelial surfaces naturally.

They have a symbiotic relationship with the body and can eradicate most normally infections

They ensure there is no undefended ecological niche

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The components of the immune system can be split into which two categories?

A
  1. Cells
  2. Humoral immunity (soluble factors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which 3 main groups of cells are involved in the immune system?

A
  1. Phagocytes
  2. Lymphocytes
  3. Granular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When a cell is infected with a virus what will it secrete?

A

Interferons (alpha and beta)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The antiviral state inititiated by interferons achieves what?

A

It down regulates protein synthesis which slows virus production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an antigen?

A

An substance able to stimulate an adaptive immune response - it can be protein, carbohydrate, nucleic acid, lipid, metal etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where are T and B cells formed?

A

Bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where do B cells mature?

A

Bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where do T cells mature?

A

Thymus gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In response to an infection B cells will produce what?

A

Antibodies and memory cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the two types of T cell?

A

Helper T cell (CD4+)

Cytotoxic T cell (CD8+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does a virus evade the immune system?

A

It will usually hide within body cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can cytotoxic T cells discover viruses hiding in body cells?

A

The host cell constantly samples its cytoplasm and displays proteins on its surface - this is mediated by MHC class 1 proteins

These displayed proteins can “show” cytotoxic T cells which cells are infected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do viruses evade the process of cytoplasm sampling mediated by MHC class I proteins?

A

They downregulate the production of MHC class I proteins

This reduced cytoplasm sampling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do natural killer (NK) cells retaliate to viruses that downregulate MHC class I production?

A

NK cells can detect a lack of MHC class I proteins on a cell surface

They can then attack and destroy such cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How are parastitic works (helminths) attacked by the immune system?

A

Antibodies and mast cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the complement system and where is it produced?

A

Family of around 30 different proteins produced in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does the complement system function?

A

When activated, the proteins activate eachother in a cascade fashion

This involves great amplification and playes a role in inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When do monocytes differentitate into macrophages?

A

When they exit the blood and migrate to peripheral tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are Kupffer cells?

A

Macrophages of the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are mesangial cells?

A

Macrophages of the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are macrophages of the nervous sytem called?

A

Microglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How can neutrophils be differentiated from macrophages?

A

Their multi-lobed nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the role of dendritic cells?

A

They engulf pathogens, phagoytose and then present antigens on their surface to T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the main functions of neutrophils?

A

Killing and degredation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the main functions of macrophages?

A

Killing, degregation, wound healing, anti-inflammatory and antigen presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the main fucntion of dendritic cells?

A

Antigen presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is lymphodema and why may it result in infection?

A

It a condition characterised by a lack of draining of tissue fluid by the lymphatic system

The fluid builds up and is not cleaned as effectively leading, potentially, to infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

The immune system itself is composed of two halves - what are these halves and how are they connected?

A
  1. Innate immune system
  2. Adaptive immune system

Joined through the action of dendritic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is meant by “direct contact” between immune cells and pathogens?

A

A receptor/ligand interaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is meant by “indirect contact” in the immune system?

A

Communication between cells and pathogens through the use of cytokines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are autocrine signals?

A

Signals produced by a cell that lead to self-activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Interferons have the role of activating an _______ ______

A

Antiviral state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which cells may secrete interferons?

A

Infected cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Release of interferons has two main outcomes, what are they?

A
  1. Protein synthesis is downregulated
  2. Employment of particlular mlcules into the cell membrane is upregulated such as MHC class I - allows for detection

Interferons can also instruct cells to undergo apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are the signs of acute infammation?

A
  • Redness - vasodilation
  • Swelling - vascualr permeability
  • Heat - high metabolic function
  • Pain
  • Loss of function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the three phases of the innate response?

A
  1. Recognition
  2. Activation
  3. Effector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Describe recognition as a phase in the innate response

A

Innate immune cells recognise pathogens due to the expression of PAMPs which bind to PRRs on innate immune cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are PAMPs?

A

Pathogen associated molecular patterns

These are ligands expressed on the surface of pathogens which allow them to be detected by immune cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are PRRs?

A

Pattern recognition receptors

Found on innate imune cells that are receptors for PAMPs found on pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How do macrophages differentiate between apoptotic cells and normal cells?

A

Normally phospholids called phosphatidlyserine are held facing inward to the cytoplasm by the enzyme flippase

In the event of apoptosis, phosphatidlyserine is fliiped to face outwards by the acion of the enzyme scramblase

These outward facing phosphatidlyserine lipids act as signals for macrophageal engulfment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

PAMPs have the ability to activate which three immune cells

A
  1. Macrophages
  2. Mast cells
  3. NK cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Injured cells release which type of signals?

A

Danger signals

(e.g. IL 33)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What happens when macrophages cannot kill a pathogen?

A

Infected macrophages are walled off forming granulomas

The purpose of this is to prevent the spread of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What will be present on the surface of macrophages after engulfment of a pathogen?

A

Fragments of pathogen protein

This allows for recognition by antigen presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Interferon gamma can cause what change in a macrophage?

A

It will cause superactivation

This allows for expression of inducible nitric oxide synthase - an enzyme allowing for production of toxic oxygen and nitrogen species

The antigen presentation capacity of macrophages will also increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Where are mast cells found most prominently?

A

Mucosal surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Which two processes occur when a PRR on a mast cell is bound by a PAMP?

A
  • Degranulation - release of pre-formed pro-inflammatory mediators are released allowing for acute inflammation
  • Gene expression - production of new pro-inflammatory mediators commences within mast cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Why do NK cells not kill normal helathy cells?

A

Normal cells have MHC class I protein on their surface which is bound to self proteins (antigens)

NK cells have a receptor on their surface that binds to the MHC class I protein and the antigen

When the antigen/MHC class I combination is of self-origin, inhibitory signals are sent to the NK cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How do viruses evade cytotoxic T cell killing?

A

They cannot be detected by the antigen/MHC class I receptor system because they downregulate MHC class I production meaning it is more difficult for foreign antigens to be “seen”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How do NK cells kill cells in which viruses have downregulated MHC class I production?

A

If no ligand (MHC class I + antigen) is present, NK cells cannot be inhibited so the cell is killed regardless

NK cells take no chances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Upon activation NK cells secrete pro inflammatory mediators such as _________ gamma

A

Interferon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

In what two ways are NK cells activated?

A
  1. Detection of no/foreign MHC class I
  2. Interferon alpha and beta released from infected cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Which pro-inflammatory mediator acts upon macrophages to superactivate them?

A

Interferon gamma

(produced from NK cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Which cytokines act on the hypothalamus to increase prostaglandin production?

A

TNFalpha, IL-1 and IL-6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the function of prostaglandin production by the hypothalamus during an infection?

A

Induces fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What effect do cytokines TNFalpha, IL-1 and IL-6 have on bone marrow?

A

Act on haematopoetic stem cells to drive production and differentiation of more neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is increased production of neutrophils called?

A

Neutrophilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Where is C reactive protein produced and what increases its production?

A

Liver

Pro-inflammatory mediators TNFalpha, IL-1 and IL-6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Clinically, why are CRP levels usefult to monitor?

A

They are very indicative of the level and severity of inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

CRP has which two functions in the immune system?

A
  1. Promotes phagocytosis
  2. Activates complement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What are the symptos of the local effects of inflammation?

A
  • Rubor - redness
  • Calor - heat
  • Tumour - swelling
  • Dolor - pain
  • Loss of function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Pro-inflammatory mediators can cause systematic effects as well as local ones, what are these?

A
  • Neutrophilia
  • Fever
  • Activation of complement
  • Promotion of phagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

How is vascular permeability brought about during acute inflammation?

A
  • Macrophages - TNFalpha, IL-1, NO
  • Mast cells - Histamine, TNFalpha, leukotrienes, prostaglandins
69
Q

How is vasodilatation brought about during acute inflammation?

A
  1. TNFalpha - mast cells and macrophages
  2. Histamine - mast cells
70
Q

During acute inflammation, what can cause endothelial cells within vessels to become activated?

A
  • TNFalpha - macrophages
  • IL-1 - Macrophages
  • Chemokines - macrophages
  • Histamines - mast cells
71
Q

What does endothelial cell activation involve?

A

Expression of receptors (selectins) and ligands (ICAM-1 and VCAM-1)

72
Q

Which cell types can undergo transendothelial migration?

A
  • Neutrophils
  • Monocytes
  • NK cells
  • Basophils
  • Eosinophils
  • T cells
73
Q

What is white cell margination and how does it come about?

A

Due to vasodilatation (induced by TNFalpha and histamines), there is slower blood flow (stasis) which causes white cells to move closer to the endges of vessels

74
Q

Why do neutrophils roll along the endothelial walls after white cell margination?

A

They bind via carbohydrate ligands to selectins on the endothelial walls

This attraction has low affinity meaning bonds are continually made and broken so the white cells roll along the walls

75
Q

What causes there to be strong attraction between neutrophils and the endothelial cell walls?

A

The release of chemokines from macrophages can activate neutrophils

This allows receptors on the neutrophil surface (integrins) to form strong bonds with the ICAM-1 and VCAM-1 on the endothelial cell walls

76
Q

After binding between integrins and ICAM-1/VCAM-1 occurs what occurs next to the neutrophil?

A

It will come to a halt and undergo diapedesis - the process where neutrophils squeeze through the spaces between endothelial cells and into the extracellular space

77
Q

How do neutrophils migrate to the site of inflammation after diapedesis?

A

Chemotaxis

Locomotion along a chemokine gradient

78
Q

What are the two basic functions of neutrophils?

A
  1. Kill extracellular pathogens
  2. Produce pro-inflammatory cytokines
79
Q

During phagocytosis, what are the two main ways that pathogens will be destroyed within a phagosome?

A
  1. Anti-microbial proteins
  2. NADPH oxidase dependent mechanisms
80
Q

Describe how anti-microbial proteins will kill pathogens within a phagosome

A

The phagosome fuses with azurophilic granules raising pH

This activates the antimicrobial response - pH of the phagosome decreases, lysosomes fuse and acid hydrolases enter to break down bacteria

81
Q

Describe how NADPH oxidase dependent mechanisms kill bacteria

A

Neutrophils can become activated by cytokines or PAMPs which forms the NADPH complex

This means that a highly reactive oxygen species (ROS) can now be produced and released into the phagolysosome

82
Q

What is degranulation?

A

The release of anti-microbial proteins into the extracellular space instead of within a phagolysosome

83
Q

What is the downside to degranulation an how is this negative aspect partly counteracted?

A

Release of anti-microbial proteins into extracellular space is damaging to surrounding tissues

This is counteracted by upregulation of proteinase inhibitors produced during the acute phase response

84
Q

What are NETs?

A

Neutrophil extracellular traps

Intracellular structures release by neutrophils into extracellular spaces - they function as nets to prevent spread and facilitates phagcytosis

85
Q

What is pus?

A

Collection of neutrophils, NETs, dead bacteria and cellualr debris

86
Q

What is the term given to a collection of pus within an enclosed space?

A

Abscess

87
Q

What is sepsis?

A

Blood poisoning brough about by infection

Uncontrolled inflammation causes sepsis and it can lead to septic shock due to a drop in blood pressure organ failure occurs

88
Q

What are examples of complement proteins?

A
  • Kinins
  • Coagulation factors
  • Fibrinolytic system
89
Q

How many complement proteins are there and where are they produced?

A

30

Liver

90
Q

In simple terms what activates complement?

A

Pathogens

(directly or indirectly)

91
Q

What are the three pathways in which a cascade can occur involving complement?

A
  1. Mannose-binding lectin pathway
  2. The alternative pathway
  3. The classical pathway
92
Q

Describe the classical pathway of complement activation

A
  • C1 complex is activated upon binding to an immune complex involving either IgG or IgM
  • C1 splits to C4 and C2
  • C4 becomes C4a and C4b, whilst C2 becomes C2a and C2b
  • Both C4b and C2a complex to form C4b2a (C3 convertase)
  • This enzyme allows for C3 to be cleaved into C3a and C3b
93
Q

Describe the mannose-binding lectin pathway for complement activation

A

Mannose - a bacterial carbohydrate

Mannose binding lectin is produced in the liver and binds to mannose

This initiates the breakdown of C3 to C3a and C3b

C3b contributes to an amplification loop

94
Q

Describe the alternative pathway for complement activation

A

C3 spontaneously breaks down

C3b binds to the pathogen surface and acts in amplification of the response

95
Q

How is the membrane attack complex formed and how is this achieved?

A

C3b causes breakdown of C5 into C5a and C5b

C5b binds to the surface of the pathogen

C6, 7, 8 and 9 assemble around C5b forming the membrane attack complex

This created a funnel shaped hole in the pathogen allowing for death by osmotic cell lysis

96
Q

What is opsonisation?

A

The coating of pathogens by humoral factors (opsonins) to facilitate phagocytosis

97
Q

Give some examples of opsonins

A
  • C3b
  • C-reactive protein
  • IgG and IgM
98
Q

C5a and C3a are _____________ which can act on which two things?

A

Anaphylatoxins

Acts on mast cells and blood vessels

99
Q

What effects do the anaphylatoxins C3a and C5a have on mast cells and blood vessels?

A
  • Activate mast cells to produce pro-inflammatory mediators and chemokines to increase vascular permeability and increase recruitment of macrophages, neutrophils and lymphocytes
  • Act directly on blood vessles to have the same effect as activated mast cells - increased vascular permeability and immune cell recruitment
100
Q

Why does a small signal from the complement system result in a large effect?

A

The amplification loop

101
Q

How is the amplification loop controlled in the complement system?

A
  • Only cleaved proteins are active
  • Active proteins have a short half life
  • Some complement proteins cannot bind to human cells
  • Complement inhibitors and regulatory proteins can limit the effects of complement where necessary
102
Q

In the mature state, what do dendritic cells do?

A

Enter secondary lymphoid tissues and play a role in antigen presentation to CD4+ cells

103
Q

Which “arm” of the immune system is rapid, non-specific and inborn

A

Innate

104
Q

Which “arm” of the immune system is slow, specific and acquired?

A

Adaptive

105
Q

Which cells can communicate between both “arms” of the immune system?

A

Dendritic cells

106
Q

What are the types of cells in the aquired immune system?

A
  • B cells
  • CD4+ T cells (helper)
  • CD8+ T cells (cytotoxic)
  • Memory T cells
  • Memory B cells
107
Q

How is the interaction between PAMPs and PRRs different from the interaction between antigens and antibodies?

A

The interaction between antigen and antibody is far more specific and they are not at all interchangable

108
Q

How are T cells recognised?

A

Membrane bound heterodimer (composed of alpha and beta chains)

109
Q

How are B cells recognised?

A

Membrane bound antibody (IgM or IgD)

110
Q

What are antibodies composed of?

A

Two heavy and two light polypeptide chains which are held together by di sulphide bridges

111
Q

How do heavy and light chains confer variability?

A

Each heavy and light chain has a variable region at the end and a constant domain on the rest of the chain

112
Q

What type of heavy chain does IgM have?

A

μ heavy chain

113
Q

What type of heavy chain does IgG have?

A

γ heavy chain

114
Q

What type of heavy chain does IgA have?

A

α heavy chain

115
Q

What type of heavy chain does IgE have?

A

ε heavy chain

116
Q

What type of heavy chain does IgD have?

A

𝛿 heavy chain

117
Q

In an antibody, what is the antigen binding site composed of?

A

The hypervariabe regions Ig light and heavy chains

118
Q

How is it possible that there are more antibodies than genes in the body?

A

The light and heavy chain are coded for by segmented genes in the germline genome of haematopoetic stem cells

119
Q

How are the segmented genes from the germline genome of haematopoetic stem cells arranged within B cells as they go through development?

A

They are randomly rearranged

120
Q

How is genertic material arranged during the development of T cells?

A

It is randomly rearranged

121
Q

The gene arrangement process in the development of both T and B cells gives rise to which two importnt factors?

A
  1. Populations of B cells and T cells are hugely diverse
  2. There is potential for generation of autoreactive cells
122
Q

How do naive T cells and B cells enter lymph nodes from high endothelial venules (HEVs)?

A

Transendothelial migration

123
Q

What is the function list of an immature dendritic cell?

A

Ability to phagocytose antigens, cell debris and particles

124
Q

Where do mature dendritic cells migrate to and what do they do there?

A

Secondary lymphoid tissues (lymph nodes)

Display antigens to T cells

125
Q

Which cytokine will activate immature dendritic cells?

A

TNFalpha

Induces expression of co-stimulatory molecules (B7)

(dendritic cells mature)

126
Q

How do dendritic cells present antigens?

A

In complex with MHC class I proteins on their cell surface

127
Q

Where do dendritic cells go that are presenting foreign antigens?

A

Local lymph nodes

T cells can easily recognise the foreign antigens here

128
Q

Stromal cells have what function in lymph nodes?

A

They are connective tissue cells that can bind to opsonised antigens

129
Q

For B cells to be activated, how many signals do they require?

A

2

130
Q

What signals can activate B cells?

A

The B cell receptor + antigen must always be one signal

The other signal can be any of the following:

  • TFH (helper T cell)
  • PRR + PAMP
  • Multiple BCR + antigens - repetitive antigens with multiple epitopes (areas antibodies can bind to antigen)
131
Q

What are the two classes of MHC proteins and their functions?

A

Class 1 - expressed on all nucleated cells - present peptide antigens to CD8+ T cells

Class 2 - only expressed on professional antigen presenting cells (APCs) such as dendritic cells, macrophages and B cells - they present the peptide antigen to CD4+ T cells

132
Q

What two signals do T cells require to become activated?

A
  1. Antigen + MHC protein
  2. B7 - peripheral membrane protein on APCs for co-stimulation, and CD28 - protein expressed on T cells that provides co-stimulatory signals for T cell activation (B7 and CD28 bind)
133
Q

What happens upon cell (T/B) activation?

A

Undergoes clonal expansion and differentiation into effector or memory cells

134
Q

Plasma cells are characterised by which physical feature?

A

Huge amounts of endoplasmic reticulum for protein (antibody) production

135
Q

How and why does antibody affinity for antigens vary over time after production?

A

Initially affinity of antibodies is low

After entering the germinal centre (secondary centre within B-cell area of lymph nodes) the plasma cells become long life plasma cells

They now excrete high affinity antibodies

136
Q

Antibodies are classified by the type of _______ chain they use

A

Heavy

137
Q

How many binding sites does IgM have?

A

10

138
Q

Which pathway for complement activation does IgM activate?

A

Classical

139
Q

How does IgM aid in the activation of the classical pathway of complement?

A

Upon binding to antigens of the pathogen surface it will undergo conformational change

This change provides a binding site for C1 the first component of the pathway

140
Q

As well as IgM which other antibody class can activate the classical complement activation pathway?

A

IgG

141
Q

What is the first antibody produced?

A

IgM

142
Q

What is the most abundant antibody?

A

IgG

143
Q

Which maternal antibody class will protect a growing foetus and why is this important?

A

IgG

The foetus does not have a fully developed immune system

144
Q

Describe how IgG antibodies make good opsonins and aid phagocytic cells and their detection of pathogens

A

Phagocytic cells express a Fc gamma receptor on their surface for the gamma heavy chain

This can make pathogens visible to neutrophils

145
Q

IgG antibodies are good activators of NK cells - why?

A

NK cells have receptors on their surface that interact with the gamma heavy chain of the IgG antibody

This interaction can instruct NK cells to destroy pathogens attached to IgG

146
Q

Where is IgD commonly found?

A
  • On the surface of B cells
  • In the circulatory system
147
Q

What is the role of IgD thought to be?

A

Recruitment of basophils into areas of inflammation

148
Q

What is the second most abundant antibody type?

A

IgA

149
Q

Secretory IgA is what form of IgA?

A

Dimeric form

150
Q

Secretory IgA is involved in which two main areas?

A
  1. Neonatal defence - in breast milk
  2. Neutralisation - at muscosal sites such as GI tract and in tears
151
Q

Which antibody class is involved in allergic responses?

A

IgE

152
Q

How does IgE trigger allergic responses?

A

Activates mast cells which then release pro-inflammatory mediators

153
Q

Why can mast cells and basophils be activated by IgE?

A

They have FcE receptrs for IgE on their surfaces

154
Q

Why does the level of antibodies remain elevated for an extended period of time after an encounter with a pathogen?

A

In case the body re-encounters this pathogen

155
Q

Cytokine environments can cause B cells to switch what?

A

Heavy chains

Based on the pathoehn experienced

156
Q

Which factors influence the type of helper T cell that differentiates from a CD4+ T cell?

A

Cytokines present that dendritic cells secrete

The cytokines released by dendritic cells is influeced by the type of PAMP, danger and inflammatory signals

157
Q

Effector TH cells can stimulate which other immune cells?

A
  • B cells (TFH)
  • Macrophages (TH1)
  • CD8+
  • CD4+
158
Q

Antigen activated CD4+ T cells secrete what cytokine when they proliferate in reponse to the antigen and co-stimulation?

A

IL-2

159
Q

IL-2 can stimulate which type of immune cell to do what?

A

CD8+ to differentiate into cytotoxic T cells

160
Q

How do TH1 cells enter inflamed tissue?

A

Trans-endothelial migration

161
Q

TH1 cells will express what cytokine in inflamed tissue and what is its purpose?

A

Interferon gamma

(as well as other co-stimulatory molecules)

This is to induce expression of nitrous oxide synthase in the macropage allowing the pathogen to be destroyed

This is superactivation of macrophages - similar to how NK cells do this

162
Q

What is the full process of B cell activation involving TFH cells?

A
  • Initially B cells encounter opsonised antigen and become partially activated
  • The antigen/antibody complex is internalised
  • The antigen is presented by MHC class II on the surface
  • T cells complex with the MHC class II/antigen complex which allows B cells to become fully activated
163
Q

How do TFH cells stimulate B cells to clonally proliferate?

A

Via CD40L (on TFH cell) and CD40 interactions

Effector TFH cells secrete cytokines the further activate B cells and stimulate the germinal centre response

164
Q

What does the germinal response entail?

A
  • B cell proliferation
  • Antibody heavy chain switching
  • Generation of high affinity antibodies
  • Differentiation into plasma cells
  • Differentiation into memory B cells
165
Q

What is the overall aim within the germinal centre and how is it brought about?

A

To produce high affinity antibodies by inducing mutations into heavy and light Ig chains

This is mediated by activation induced deaminase (AID) which can mutate antibodies

The downside to this is that it can cause lymphoma

166
Q

Cytotoxic T cells bind to what on infected cells?

A

MHC class I and the presenting antigen

167
Q

What do cytotoxic T cells do to infected cells?

A

Introduce pore-like structures causing osmotic lysis or by initiating apoptosis

They can express Fas ligand whcih results in the release of cytochrome c - a pro-apoptotic protein

168
Q

When there is no longer inflammation, what cytokine is released from macrophages?

A

IL-10

This stops the inflammatory respons eand initiates tissue repair

169
Q
A

Principles (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions