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BMS2052 > Host Responses to Microbial Infection > Flashcards

Host Responses to Microbial Infection Flashcards

1
Q

Definition

the second branch of immunological tolerance, after central tolerance. It takes place in the immune periphery (after T and B cells egress from primary lymphoid organs). Its main purpose is to ensure that self-reactive T and B cells which escaped central tolerance do not cause autoimmune disease.

A

Peripheral tolerance

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2
Q

The _________ is a multimolecular cytoplasmic protease

A

The proteosome is a multimolecular cytoplasmic protease

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3
Q

Triggering PRR can lead to Type ___ interferon production

A

Triggering PRR can lead to Type I interferon production

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4
Q

Define

Scavenger receptors

A

receptors on macrophages and other cells that bind to numerous ligands, such as bacterial cell-wall components, and remove them from the blood

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5
Q

What is the name of the region of the MHC that the peptide sits?

A

Peptide-binding cleft

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6
Q

What are B-cell receptors composed of?

A

2 identical heavy chains and 2 identical light chains

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7
Q

Definition

one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the C3b protein directly binds a microbe

A

Alternative pathway

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8
Q

Which cells can display cross presentation? Why does it occur?

A

Only occurs in some highly specialised dendritic cell populations and it is thought to be criticaclly important in initiating CD8 T cell responses

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9
Q

What type of cells can Type I interferons activate?

A

NK cells

Dendritic cells

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10
Q

Definition

T cell with CD8 receptor that recognizes antigens on the surface of a virus-infected cell and binds to the infected cell and kill it

A

CD8+ T-cell

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11
Q

What are the two types of lymphocytes?

A

T-cells

B-cells

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12
Q

What is the main Nod-like receptor that recognises bacterial and viral DNA and RNA?

A

NLRP3

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13
Q

What does triggering PRR do to T cell immunity?

A
  1. Increases MHC expression and promotes antigen presentation
  2. Increases costimulation
  3. Promotes cytokine production
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14
Q

Where are adaptive immune responses initiated?

A

Initiated by dendritic cells in the secondary lymphoid organs (nodes and spleen)

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15
Q

Concerning B cell responses:

Select one:

a. IFNg drives switching to some subclasses of IgG
b. The isotype first secreted by B cells is high affinity IgM
c. All B cell responses require T cell help
d. Cytokine secretion by T cells is sufficient to drive isotype switching

A

Concerning B cell responses:

Select one:

a. IFNg drives switching to some subclasses of IgG

b. The isotype first secreted by B cells is high affinity IgM
c. All B cell responses require T cell help
d. Cytokine secretion by T cells is sufficient to drive isotype switching

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16
Q

True or False:

Antigen receptors are not germline encoded

A

True

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17
Q

Define

Alternative pathway

A

one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the C3b protein directly binds a microbe

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18
Q

Which protein families are PRRs encoded by?

A

Toll-like receptors (TLR)

Lectins

Scavenger receptors

NOD-like receptors

RIG-like helicases

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19
Q

What do CD4 cells differentiate into?

A

Thelper cells

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20
Q

Definition

conserved molecular structures produced by microorganisms and recognized as foreign by the receptors of the innate immune system

A

Pathogen associated molecular patterns (PAMPs)

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21
Q

How are peptides displayed on MHC I?

A
  • Cellular proteins are degraded in the cytoplasm by the proteasome
  • Peptides are pumped into the endoplasmic reticulum by TAP, where the bind to class I MHC
  • Class I MHC/peptide is then transported to the cell surface
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22
Q

Define

Chemokines

A

a family of small cytokines, or signaling proteins secreted by cells. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells

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23
Q

Define

Ubiquitin

A

a compound found in living cells which plays a role in the degradation of defective and superfluous proteins. It is a single-chain polypeptide

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24
Q

What does IL-12 do in the inflammatory response?

A

Activates NK cells

Induces the differentiation of CD4 T cells into Thelper cells

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25
Q

What are the three types of antigen presenting cells?

A

Dendritic cell

Macrophage

B lymphocyte

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26
Q

Definition

a heterogeneous group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells

A

Antigen presenting cells (APC)

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27
Q

Definition

A substance that is produced by a predecessor protein or in response to the presence of foreign material in the body and that triggers or participates in a complement reaction

A

Complement

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28
Q

Define

Mannose binding lectin

A

a lectin that is instrumental in innate immunity as an opsonin and via the lectin pathway

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29
Q

Definition

a biochemical process in the blood that helps or ‘complements’ cells of the immune system to eliminate invading pathogens

A

Complement cascade

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30
Q

Definition

a colourless cell which circulates in the blood and body fluids and is involved in counteracting foreign substances and disease; a white (blood) cell. There are several types, all amoeboid cells with a nucleus, including lymphocytes, granulocytes, and monocytes

A

Leukocytes

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31
Q

Which complement(s) are responsible for opsonisation and phagocytosis?

A

C3b

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32
Q

Definition

A protein that transports a peptide from the cytoplasm into the lumen of the endoplasmic reticulum

A

TAP

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33
Q

What determines the specificity of MHC molecules?

A

The amino acids in MHC that contact the peptides determine precisely which peptide an MHC molecule can present

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34
Q

Which complement protein is the most potent?

A

C5a

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35
Q

Definition

a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated complement proteins further down the cascade

A

Lectin pathway

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36
Q

How many different PRRs does a single innate immune cell express?

A

Many

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37
Q

Which region of the MHC does alleleic variation occur?

A

Peptide-binding region

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38
Q

Definition

the process of eliminating any developing T or B lymphocytes that are reactive to self. Through elimination of autoreactive lymphocytes, tolerance ensures that the immune system does not attack self peptides

A

Central tolerance

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39
Q

What happens in the Alternative pathway?

A

C3 is activated and binds directly to the pathogen surface (via a chemical reaction) - non-specific

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40
Q

Define

TAP

A

A protein that transports a peptide from the cytoplasm into the lumen of the endoplasmic reticulum

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41
Q

Define

Leukocytes

A

a colourless cell which circulates in the blood and body fluids and is involved in counteracting foreign substances and disease; a white (blood) cell. There are several types, all amoeboid cells with a nucleus, including lymphocytes, granulocytes, and monocytes

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42
Q

Definition

the process by which T cells and B cells randomly assemble different gene segments – known as variable, diversity and joining genes – in order to generate unique receptors (known as antigen receptors) that can collectively recognize many different types of molecule

A

VDJ recombination

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43
Q

What are the adhesion molecules that allow leukocytes to stably ashere?

A

Integrins

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44
Q

Define

Pathogen associated molecular patterns (PAMPs)

A

conserved molecular structures produced by microorganisms and recognized as foreign by the receptors of the innate immune system

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45
Q

Definition

one of two primary classes of major histocompatibility complex (MHC) molecules and are found on the cell surface of all nucleated cells in the bodies of jawed vertebrates. They also occur on platelets, but not on red blood cells.

A

MHC I

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46
Q

Definition

any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells

A

Cytokines

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47
Q

What are the two major types of MHC?

A

Class I

Class II

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48
Q

Define

CD8+ T-cell

A

T cell with CD8 receptor that recognizes antigens on the surface of a virus-infected cell and binds to the infected cell and kill it

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49
Q

True or False:

MHC is expressed co-dominantly

A

True

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50
Q

Definition

an interleukin that is naturally produced by dendritic cells, macrophages, neutrophils, and human B-lymphoblastoid cells (NC-37) in response to antigenic stimulation

A

IL12

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51
Q

Define

IL6

A

an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine

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52
Q

What are the first blood cell to arrive at the site of infection?

A

Neutrophils

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53
Q

What are the key features of the adaptive immune system?

A

Specificity

  • Immunity to a particular antigen due to:
    • Specific antigen receptors on T and B cells
    • Specificity of antibody molecules and effector T cells

Diversity

  • Extremely large number of lymphocyte clones, each with a particular antigen specificity
  • At least 109 distinct antigenic determinants can be recognised

Discrimination between self and non-self

  • Normally immune receptors are to foreign antigens and not to self antigens
  • Self-tolerance is established during development of the immune system

Memory

  • Primary and secondary immune responses
  • Secondary immune response is always greater in magnitude

Self-regulation

  • Immune responses are self-limiting
  • Antigen cleared from the system
  • Lymphocyte lifespan
  • Feedback mechanisms
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54
Q

What does activation of PRR lead to in innate immune cells?

A
  • Inflammatory response
  • Type I interferon production
  • The oxidative burst
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55
Q

The T-cell receptor recognised peptide antigen presented by what?

A

MHC

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56
Q

Definition

One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. Made mainly by macrophages, and helps the lymphocytes fight infections.

A

IL-1β

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57
Q

MHC I tends to display intracellular/extracellular peptides

A

MHC I tends to display intracellular​ peptides

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58
Q

What are the 2 major types of T lymphocyte?

A

CD4+ T-cells

CD8+ T-cells

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59
Q

True or False:

MHC is the same in everyone

A

False

MHC is highly polymorphic

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60
Q

How are peptides displayed on MHC II?

A
  • Extracellular proteins are endocytosed/phagocytosed
  • Proteins are degraded by the lysosome
  • MHC class II is generated in the ER, in association with the invariant chain MIIC vesicle
  • MHC vesicles fuse with endo/lysosomes, peptides are loaded onto Class II in MIIC vesicles
  • MHC II/peptide is exported to the cell surface
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61
Q

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 4: HLA-A, HLA-B, HLA-C, HLA-D
b. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR
c. 3: HLA-DP, HLA-DQ, HLA-DR.
d. 1: HLA-class II

A

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 4: HLA-A, HLA-B, HLA-C, HLA-D

b. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR

c. 3: HLA-DP, HLA-DQ, HLA-DR.
d. 1: HLA-class II

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62
Q

Define

Cytokines

A

any of a number of substances, such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells

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63
Q

Define

B-cell

A

a lymphocyte not processed by the thymus gland, and responsible for producing antibodies

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64
Q

Define

Lectin pathway

A

a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated complement proteins further down the cascade

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65
Q

Definition

adhesion molecules that allow leukocytes to stably adhere

A

Integrins

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66
Q

The adaptive immune system works via ______ selection

A

The adaptive immune system works via clonal selection

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67
Q

Definition

A type of immune cell that is one of the first cell types to travel to the site of an infection

A

Neutrophil

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68
Q

Definition

antigen-presenting cells(also known as accessory cells) of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems.

A

Dendritic cell

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69
Q

Define

Mast cell

A

a cell filled with basophil granules, found in numbers in connective tissue and releasing histamine and other substances during inflammatory and allergic reactions.

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70
Q

Definition

a lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response.

A

T-cell

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71
Q

Definition

a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction.

A

TNFα

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72
Q

What 3 signals from antigen presenting cells are needed by T-cells?

A
  1. Antigen + MHC
  2. Costimulation (CD80 and CD86)
  3. Cytokines to differentiate T cells into effector cells
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73
Q

Define

Complement

A

A substance that is produced by a predecessor protein or in response to the presence of foreign material in the body and that triggers or participates in a complement reaction

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74
Q

What happens in the Classical pathway?

A

C3 is activated by antibody (IgM and IgG) bound to antigen

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75
Q

How many receptor types does each lymphocyte have?

A

One

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76
Q

When is self-tolerance developed?

A

During development of the immune system

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77
Q

Define

Integrins

A

adhesion molecules that allow leukocytes to stably adhere

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78
Q

Definition

a class of proteins that play a key role in the innate immune system. They are single, membrane-spanning, non-catalytic receptors usually expressed on sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from microbes

A

Toll-like receptors

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79
Q

What are the characteristics of activated/mature dendritic cells?

A
  • Low phagocytosis
  • High MHC II (high Ag presentation)
  • High co-stimulation
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80
Q

What happens in the Lectin pathway?

A

C3 is activated by mannose binding lectin (a soluble recognition receptro found in serum) that binds to mannose residues found exclusively on surface glycoproteins of microbes

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81
Q

What are Type I interferons?

A

Cytokines with potent antiviral activity

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82
Q

Which parts of microbes can be recognised by Toll-like receptors?

A

Diacyl lipopeptides

Triacyl lipopeptides

Flagella

LPS

CpG DNA

ssRNA

dsRNA

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83
Q

Dendritic cells activated by _______ migrate from the periphery to _________

A

Dendritic cells activated by PAMPs migrate from the periphery to draining lymph node

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84
Q

What are the Type I interferons?

A

IFNα

IFNβ

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85
Q

What is required for an NK cell to kill another cell?

A

Activation of their activation receptor (stress ligand receptor)

No activation of their inhibitory receptor (indicates no MHC I present)

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86
Q

What does IL-1 do in the inflammatory response?

A

Activates vascular endothelium

Activates lympocytes

Local tissue destruction

Increased access of effector cells

Leads to fever

Leads to production of IL-6

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87
Q

Define

Toll-like receptors

A

a class of proteins that play a key role in the innate immune system. They are single, membrane-spanning, non-catalytic receptors usually expressed on sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from microbes

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88
Q

Define

Macrophage

A

a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.

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89
Q

Define

NOD-like receptors

A

a group of pattern recognition receptors that are expressed in the cell cytosol. They can sense molecules that are associated with infection (for example, bacterial peptidoglycans) and induce inflammatory immune responses that help clear the infection

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90
Q

What is TAP?

A

An ATP-dependent peptide pump that is embedded in the ER membrane an pumps peptides from the cytoplasm to the lumen of the ER

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91
Q

What are the two major branches of the immune syste?

A

Innate and adaptive

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92
Q

Define

Lymphocytes

A

a form of small leucocyte (white blood cell) with a single round nucleus, occurring especially in the lymphatic system

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93
Q

What pro-inflammatory cytokines and chemokines are involved in the inflammatory response?

A

Cytokines: IL-1, IL-6, TNF-α, IL-12

Chemokines: CXCL8

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94
Q

What does TNF-α do in the inflammatory response?

A

Activates vascular endothelium

Increases vascular permeability which leads to increased entry of IgG, complement and cells to tissues and increase fluid drainage to lymph node

Leads to fever

Leads to mobilisation of metabolites

Can lead to shock

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95
Q

Define

Natural Killer (NK) cells

A

a lymphocyte able to bind to certain tumour cells and virus-infected cells without the stimulation of antigens, and kill them by the insertion of granules containing perforin

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96
Q
A
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97
Q

Define

RIG-like helicases

A

a type of intracellular pattern recognition receptor involved in the recognition of viruses by the innate immune system

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98
Q

Define

Dendritic cell

A

antigen-presenting cells(also known as accessory cells) of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems.

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99
Q

Definition

a cell filled with basophil granules, found in numbers in connective tissue and releasing histamine and other substances during inflammatory and allergic reactions.

A

Mast cell

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100
Q

Why is there an evolutionary advantage for offspring to have diversity in MHC?

A

To protect from disease

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101
Q

Which cells express MHC class II?

A

Antigen presenting cells

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102
Q

Define

TNFα

A

a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction.

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103
Q

Define

MHC I

A

one of two primary classes of major histocompatibility complex (MHC) molecules and are found on the cell surface of all nucleated cells in the bodies of jawed vertebrates. They also occur on platelets, but not on red blood cells.

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104
Q

Why is MHC a major barrier to transplantation?

A

The immune system recognised allogeneic MHC as foreign

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105
Q

NK cells can kill stressed/infected cells that lose expression of ________

A

NK cells can kill stressed/infected cells that lose expression of MHC I

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106
Q

Which cells express MHC class I?

A

All nucleated cells (so not blood cells)

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107
Q

Only _________ cells can initated the adaptive immune response

A

Only dendritic cells can initated the adaptive immune response

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108
Q

What chemicals are used to kill microbes that have been phagocytosed?

A

ROS, NO and lysosomal enzymes

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109
Q

Definition

a form of small leucocyte (white blood cell) with a single round nucleus, occurring especially in the lymphatic system

A

Lymphocytes

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110
Q

Which complement(s) are responsible for lysis of microbe?

A

C6-9

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111
Q

Definition

an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine

A

IL6

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112
Q

Definition

a type of intracellular pattern recognition receptor involved in the recognition of viruses by the innate immune system

A

RIG-like helicases

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113
Q

What is CD4?

A

CD4 is a cell surface molecule that can bind, in a peptide independent manner, to MHC class II

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114
Q

What does CXCL8 do in the inflammatory response?

A

Chemotactic factor recruits neutrophils, basophils and T cells to site of infection

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115
Q

Define

CD4+ T-cell

A

cells that help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes(B cells), and CD8 T lymphocytes (CD8 cells), to fight infection

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116
Q

What do T-cells and B-cells recognise?

A

T-cells recognise peptide antigen presented by MHC

B-cells (antibody) recognises free antigens

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117
Q

Started onWednesday, 4 September 2019, 12:42 AM

StateFinished

Completed onWednesday, 4 September 2019, 12:44 AM

Time taken1 min 39 secs

Grade2.00 out of 4.00 (50%)

Question 1

Incorrect

Mark 0.00 out of 1.00

Question text

Pattern Recognition Receptor(s):

Select one:

a. Are generated by recombination of V, D and J gene segments during lymphocyte development
b. Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells
c. Are cell surface membrane proteins that recognise Pathogen Associated Molecular Patterns (PAMPs) shared by pathogens
d. Recognise pathogens non-specifically

Feedback

Your answer is incorrect.

The correct answer is: Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells

Question 2

Correct

Mark 1.00 out of 1.00

Question text

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 4: HLA-A, HLA-B, HLA-C, HLA-D
b. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR
c. 3: HLA-DP, HLA-DQ, HLA-DR.
d. 1: HLA-class II

Feedback

Your answer is correct.

The correct answer is: 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR

Question 3

Incorrect

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Question text

Which one of the following statements about IgG is true?

Select one:

a. It is a low avidity and high affinity antibody isotype.
b. Greater levels are found in serum in week one post-infection relative to week three.
c. It is the only isotype found on the surface of B cells.
d. It is a potent trigger of anaphylaxis

A

Started onWednesday, 4 September 2019, 12:42 AM

StateFinished

Completed onWednesday, 4 September 2019, 12:44 AM

Time taken1 min 39 secs

Grade2.00 out of 4.00 (50%)

Question 1

Incorrect

Mark 0.00 out of 1.00

Question text

Pattern Recognition Receptor(s):

Select one:

a. Are generated by recombination of V, D and J gene segments during lymphocyte development
b. Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells
c. Are cell surface membrane proteins that recognise Pathogen Associated Molecular Patterns (PAMPs) shared by pathogens
d. Recognise pathogens non-specifically

Feedback

Your answer is incorrect.

The correct answer is: Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells

Question 2

Correct

Mark 1.00 out of 1.00

Question text

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 4: HLA-A, HLA-B, HLA-C, HLA-D
b. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR
c. 3: HLA-DP, HLA-DQ, HLA-DR.
d. 1: HLA-class II

Feedback

Your answer is correct.

The correct answer is: 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR

Question 3

Incorrect

Mark 0.00 out of 1.00

Question text

Which one of the following statements about IgG is true?

Select one:

a. It is a low avidity and high affinity antibody isotype.

b. Greater levels are found in serum in week one post-infection relative to week three.
c. It is the only isotype found on the surface of B cells.
d. It is a potent trigger of anaphylaxis

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118
Q

True or False:

The innate immune system is non-specific

A

False

The innate immune system can distinguish between diacyl and triacyl lipopeptides

119
Q

Define

Lectins

A

any of a class of proteins, chiefly of plant origin, which bind specifically to certain sugars and so cause agglutination of particular cell types

120
Q

Define

T-cell

A

a lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response.

121
Q

What are T-cell receptors composed of?

A

An alpha and a beta chain

122
Q

What are the immunological consequences of complement activation?

A

Inflammation (leukocyte recruitment), opsonisation (phagocytosis) and bacterial lysis

123
Q

Define

IL12

A

an interleukin that is naturally produced by dendritic cells, macrophages, neutrophils, and human B-lymphoblastoid cells (NC-37) in response to antigenic stimulation

124
Q

Definition

a cytokine that provides one of the first lines of host defense against virus infection and can rapidly protect cell culture against infection by all FMDV serotypes

A

Type I interferon

125
Q

Triggering PRR activates the oxidative burst in _________

A

Triggering PRR activates the oxidative burst in phagocytes

126
Q

Definition

adhesion molecules that allow leukocytes to roll on the vascular endothelium

A

Selectins

127
Q

What receptors do NK cells have?

A
  • Activated receptors that recognise stress ligands on infected cells
  • Inhibitory receptors that recognise MHC I
128
Q

How do innate immune cells recognised pathogens as foreign?

A

Pattern recognition receptors (PRR) recognise structures shared by many microbes

129
Q

Define

Type I interferon

A

a cytokine that provides one of the first lines of host defense against virus infection and can rapidly protect cell culture against infection by all FMDV serotypes

130
Q

Why is the invariant chain essential in MHC II antigen processing?

A
  • The invariant chain blocks the peptide binding groove in the ER lumen (to prevent MHC II binding endogenous peptide)
  • It directs MHC II to the MIIC vesicles, here it is degraded to form CLIP peptide which continues to block the groove
  • CLIP is exchanged for exogenous peptides, a reaction catalysed by HLA-DM
131
Q

Definition

a lymphocyte able to bind to certain tumour cells and virus-infected cells without the stimulation of antigens, and kill them by the insertion of granules containing perforin

A

Natural Killer (NK) cells

132
Q

Definition

any of a class of proteins, chiefly of plant origin, which bind specifically to certain sugars and so cause agglutination of particular cell types

A

Lectins

133
Q

Define

Antigen presenting cells (APC)

A

a heterogeneous group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells

134
Q

Define

MHC II

A

a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses.

135
Q

Define

Selectins

A

adhesion molecules that allow leukocytes to roll on the vascular endothelium

136
Q

What molecules allow leukocytes to roll on the vascular endothelium?

A

Selectins

137
Q

Definition

a chemokine produced by macrophages and other cell types such as epithelial cells, airway smooth muscle cells and endothelial cells

A

CXCL8

138
Q

Define

Peripheral tolerance

A

the second branch of immunological tolerance, after central tolerance. It takes place in the immune periphery (after T and B cells egress from primary lymphoid organs). Its main purpose is to ensure that self-reactive T and B cells which escaped central tolerance do not cause autoimmune disease.

139
Q

Proteins targeted for destruction are conjugated with which small protein?

A

Ubiquitin

140
Q

Why is extreme MHC diversity important?

A

To make sure that all viral proteins can be displayed

141
Q

MHC II tend to display intracellular/extracellular peptide

A

MHC II tend to display extracellular ​peptide

142
Q

Definition

a lectin that is instrumental in innate immunity as an opsonin and via the lectin pathway

A

Mannose binding lectin

143
Q

Definition

The primary pathway in the innate immune system, consisting of the activation of complement by an antigen-antibody complex

A

Classical pathway

144
Q

How is complement activated?

A

Complement is activated in 3 ways:

  • Alternative pathway
  • Lectin pathway
  • Classical pathway
145
Q

Pattern Recognition Receptor(s):

Select one:

a. Are generated by recombination of V, D and J gene segments during lymphocyte development
b. Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells
c. Are cell surface membrane proteins that recognise Pathogen Associated Molecular Patterns (PAMPs) shared by pathogens
d. Recognise pathogens non-specifically

A

Pattern Recognition Receptor(s):

Select one:

a. Are generated by recombination of V, D and J gene segments during lymphocyte development

b. Signalling leads to increased phagocytosis, pro-inflammatory cytokine production, activation of the vascular epithelium and increased co-stimulatory activity by antigen presenting cells

c. Are cell surface membrane proteins that recognise Pathogen Associated Molecular Patterns (PAMPs) shared by pathogens
d. Recognise pathogens non-specifically

146
Q

What costimulatory molecules are displayed by antigen presenting cells?

A

CD80 and CD86

147
Q

Definition

membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell

A

Endosomes

148
Q

What does IL-6 do in the inflammatory response?

A

Lymphocyte activation

Increased antibody production

Leads to fever

Induces acute-phase protein production

149
Q

Definition

a family of small cytokines, or signaling proteins secreted by cells. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells

A

Chemokines

150
Q

Definition

cells that help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes(B cells), and CD8 T lymphocytes (CD8 cells), to fight infection

A

CD4+ T-cell

151
Q

CD8+ T-cells recognised class __ MHC

A

CD8+ T-cells recognised class I MHC

152
Q

Which of the branches of the immune system is essential early in infection?

A

Innate immune system

153
Q

Define

Endosomes

A

membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell

154
Q

CD4+ T-cells recognised class __ MHC

A

CD4+ T-cells recognised class II MHC

155
Q

What is cell mediated immunity?

A

The form of adaptive immunity that is mediated by T lymphcytes

156
Q

Which complement(s) is responsible for initial inflammation?

A

C3a

157
Q

Definition

play a key role in the innate immune response by recognizing conserved pathogen associated molecular patterns(PAMPs) which are unique to each pathogen, and are essential molecular structures required for the pathogens survival.

A

Pattern Recognition Receptors (PRR)

158
Q

Definition

a lymphocyte not processed by the thymus gland, and responsible for producing antibodies

A

B-cell

159
Q

What do CD8 cell differentiate into?

A

Cytotoxic T-cells

160
Q

Define

Complement cascade

A

a biochemical process in the blood that helps or ‘complements’ cells of the immune system to eliminate invading pathogens

161
Q

Definition

a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.

A

Macrophage

162
Q

Define

Neutrophil

A

A type of immune cell that is one of the first cell types to travel to the site of an infection

163
Q

Define

IL-1β

A

One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. Made mainly by macrophages, and helps the lymphocytes fight infections.

164
Q

How many major class I and major class II genes are there?

A

3 Major class I genes: HLA-A, HLA-B and HLA-C

3 Major class II genes: HLA-DP, HLA-DQ and HLA-DR

165
Q

What are the characteristics of quiescent/immature dendritic cells?

A
  • Highly phagocytic
  • Low MHC II (low Ag-presentation)
  • Low co-stimulation
166
Q

How many different major MHC genes do we each express?

A

12

Maternal: class I x 3 + class II x 3

Paternal: class I x 3 + class II x 3

167
Q

Define

Classical pathway

A

The primary pathway in the innate immune system, consisting of the activation of complement by an antigen-antibody complex

168
Q

Definition

a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses.

A

MHC II

169
Q

Which complement(s) are resonsible for late inflammation?

A

C5a

170
Q

Where in the cell can PRRs be expressed?

A

Cell surface, endosomes and in the cytoplasm

171
Q

Define

Central tolerance

A

the process of eliminating any developing T or B lymphocytes that are reactive to self. Through elimination of autoreactive lymphocytes, tolerance ensures that the immune system does not attack self peptides

172
Q

Define

VDJ recombination

A

the process by which T cells and B cells randomly assemble different gene segments – known as variable, diversity and joining genes – in order to generate unique receptors (known as antigen receptors) that can collectively recognize many different types of molecule

173
Q

What is CD8?

A

CD8 is a cell surface molecule that can bind to MHC class I in a peptide independent manner

174
Q

What are the two types of tolerance developed to self-cells?

A

Central tolerance: self reactive lymphocytes are deleted during development in the thymus or bone marrow

Peripheral tolerance: Some self-reactive lymphocytes escape deletion. Peripheral tolerance mechanism keeps them in check

175
Q

Definition

receptors on macrophages and other cells that bind to numerous ligands, such as bacterial cell-wall components, and remove them from the blood

A

Scavenger receptors

176
Q

Define

Pattern Recognition Receptors (PRR)

A

play a key role in the innate immune response by recognizing conserved pathogen associated molecular patterns(PAMPs) which are unique to each pathogen, and are essential molecular structures required for the pathogens survival.

177
Q

True or False:

PRR undergo VDJ recombination

A

False

They are germline encoded

178
Q

How does triggering PRR lead to an inflammatory response?

A
  • Bacteria trigger macrophages to release cytokines and chemokines
  • Vasodilation and increased vascular permeability cause redness, heat and swelling
  • Inflammatory cells migrate into tissue, releasing inflmmatory mediators that cause pain
179
Q

Why is the secondary immune response always greater in magnitude?

A

Due to memory T and B cells generated during first contact with antigen

180
Q

What type of protein are most complement? What does this allow?

A

Many complement proteins are proteases which cleave one another sequentially to form the complement cascade

181
Q

How many hypervariable loops come together to form the antigen binding site?

A

6

182
Q

Definition

a group of pattern recognition receptors that are expressed in the cell cytosol. They can sense molecules that are associated with infection (for example, bacterial peptidoglycans) and induce inflammatory immune responses that help clear the infection

A

NOD-like receptors

183
Q

Define

CXCL8

A

a chemokine produced by macrophages and other cell types such as epithelial cells, airway smooth muscle cells and endothelial cells

184
Q

What happens during costimulation?

A
  • APC display costimulatory molecules CD80 and CD86 (B7.1 and B7.2)
  • These interact with the T cell molecule CD28
  • CD28 transduces signals (signal 2) that synergise with signal 1 and lead to T cell proliferation
185
Q

Definition

a compound found in living cells which plays a role in the degradation of defective and superfluous proteins. It is a single-chain polypeptide

A

Ubiquitin

186
Q

What is crosspresentation?

A
  • Crosspresentation is an exception to the MHC I/endogenous antigen, MHC II/exogenous antigen rule.
  • Here exogenous antigen escapes the phagolysosome, and enters the cytoplasm
  • It then enters the ER and therefore the class I pathway
187
Q

Define

Adaptive humoral mediated immunity

A

the form of adaptive immunity that is mediated by B lymphocytes

188
Q

Define

Granzymes

A

serine proteases released by cytoplasmic granules within cytotoxic T cells and natural killer (NK) cells. They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infected with viruses or bacteria

189
Q

Define

IgA

A

an antibody that plays a crucial role in the immune function of mucous membranes

190
Q

Define

IgD

A

an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually co-expressed with another cell surface antibody called IgM

191
Q

Define

IgE

A

a type of antibody produced by the immune system. If you have an allergy, your immune system overreacts to an allergen by producing this antibody type

192
Q

Define

IgG

A

a type of antibody. Representing approximately 75% of serum antibodies in humans, it is the most common type of antibody found in blood circulation

193
Q

Define

IgM

A

one of several isotypes of antibody (also known as immunoglobulin) that are produced by vertebrates. It is the largest antibody, and it is the first antibody to appear in the response to initial exposure to an antigen

194
Q

Define

Opsonisation

A

the molecular mechanism whereby molecules, microbes, or apoptotic cells are chemically modified to have a stronger attraction to the cell surface receptors on phagocytes and NK cells

195
Q

Define

Perforin

A

a pore forming cytolytic protein found in the granules of cytotoxic T lymphocytes (CTLs) and Natural Killer cells (NK cells)

196
Q

Define

Plasma cells

A

white blood cells that originate in the bone marrow and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens

197
Q

Define

Th1

A

A type of T-helper cell that produce interferon-gamma, interleukin (IL)-2, and tumour necrosis factor (TNF)-beta, which activate macrophages and are responsible for cell-mediated immunity and phagocyte-dependent protective responses

198
Q

Define

Th17

A

play a critical role in the induction of the tissue inflammation and tissue destruction that are hallmarks of many immune-inflammatory diseases

199
Q

Define

Th2

A

A type of T-helper cell that produce IL-4, -5, -10, and -13 and help regulate humoral immune responses to extracellular parasites and bacterial infections

200
Q

Definition

the form of adaptive immunity that is mediated by B lymphocytes

A

Adaptive humoral mediated immunity

201
Q

Definition

serine proteases released by cytoplasmic granules within cytotoxic T cells and natural killer (NK) cells. They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infected with viruses or bacteria

A

Granzymes

202
Q

Definition

an antibody that plays a crucial role in the immune function of mucous membranes

A

IgA

203
Q

Definition

an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually co-expressed with another cell surface antibody called IgM

A

IgD

204
Q

Definition

a type of antibody produced by the immune system. If you have an allergy, your immune system overreacts to an allergen by producing this antibody type

A

IgE

205
Q

Definition

a type of antibody. Representing approximately 75% of serum antibodies in humans, it is the most common type of antibody found in blood circulation

A

IgG

206
Q

Definition

one of several isotypes of antibody (also known as immunoglobulin) that are produced by vertebrates. It is the largest antibody, and it is the first antibody to appear in the response to initial exposure to an antigen

A

IgM

207
Q

Definition

the molecular mechanism whereby molecules, microbes, or apoptotic cells are chemically modified to have a stronger attraction to the cell surface receptors on phagocytes and NK cells

A

Opsonisation

208
Q

Definition

a pore forming cytolytic protein found in the granules of cytotoxic T lymphocytes (CTLs) and Natural Killer cells (NK cells)

A

Perforin

209
Q

Definition

white blood cells that originate in the bone marrow and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens

A

Plasma cells

210
Q

Definition

A type of T-helper cell that produce interferon-gamma, interleukin (IL)-2, and tumour necrosis factor (TNF)-beta, which activate macrophages and are responsible for cell-mediated immunity and phagocyte-dependent protective responses

A

Th1

211
Q

Definition

play a critical role in the induction of the tissue inflammation and tissue destruction that are hallmarks of many immune-inflammatory diseases

A

Th17

212
Q

Definition

A type of T-helper cell that produce IL-4, -5, -10, and -13 and help regulate humoral immune responses to extracellular parasites and bacterial infections

A

Th2

213
Q

What do Th1 cells do?

A

Activate macrophages to kill intracellular bacteria

214
Q

What do Th2 cells do?

A

Destroy helminths

215
Q

What do Th17 cells do?

A

Mobilise neutrophils to kill rapidly proliferating extracellular bacteria

216
Q

What three signals from antigen-presenting cells are required by T-cells?

A
  1. Antigen + MHC
  2. Costimulation (CD80 and CD86)
  3. Cytokines to differentiate T-cells into effector cells
217
Q

What do CD4+ cells do?

A

Activation of macrophages, B-cells and other cells

218
Q

What do CD8+ cells do?

A

Killing of infected cells; macrophage activation

219
Q

What are the major types of CD4 T-cells?

A

Th1

Th2

Th17

220
Q

Which cytokines are produced by Th1 cells in response to intracellular pathogens?

A

IFNγ

221
Q

Which cells are activated by the IFNγ released by Th1 cells?

A

Macrophages (mainly)

222
Q

What is the role of Th1 cells in disease?

A

Autoimmunity

Chronic inflammation

223
Q

Which cytokines are produced by Th2 cells in response to parasites?

A

IL-4

IL-5

IL-13

224
Q

Which cells are activated by the IL-4, -5 and -13 produced by Th2 cells?

A

Eosinophils

225
Q

What is the role of Th2 cells in disease?

A

Allergy

226
Q

Which cytokines are produced by Th17 cells in response to extracellular pathogens?

A

IL-17

IL-22

227
Q

Which cells are activated by the IL-17 and -22 produced by Th17 cells?

A

Neutrophils

228
Q

Which CD4 cells are important for fighting bacteria and viruses?

A

Th1 and Th17 cells

229
Q

Do CD4 T-cells recognise peptides displayed from MHC I or MHCII?

A

MHCII

230
Q

Which categorie of interferon does IFNγ fit into?

A

Type II interferon

231
Q

Which cytokines are required for the maturity of Th1 cells from Th0 precurosors?

A

IL-12

IFNγ

232
Q

Which cytokines are required for the maturity of Th2 cells from Th0 precurosors?

A

IL-4

233
Q

Which cytokines are required for the maturity of Th17 cells from Th0 precurosors?

A

TGFβ

IL-6

IL-23

IL-1β

234
Q

Which cells produce the cytokines responsible for the differentiation of Th0 cells?

A

Dendritic cells (and other immune cells)

235
Q

Early in an immune response, _________ are a source of IL-12 and ___________ a good source of IFNγ

A

Early in an immune response, dendritic cells are a source of IL-12 and natural killer cells a good source of IFNγ

236
Q

Early in an immune response, ___________ and _____________ are a good source of IL-1, -6 -23 and TGFβ

A

Early in an immune response, dendritic cells and macrophages are a good source of IL-1, -6 -23 and TGFβ

237
Q

Which cells have receptors for IFNγ? What does activation do?

A

Macrophages have receptors for IFNγ

IFNγ activates macrophages to become superb killers of intracellular microorganisms

238
Q

What is the second way (other than IFNγ) that Th1 cells activate macrophages?

A

Th1 cells express CD40 ligands for which macrophages have a receptor for

239
Q

What do macorphages do in response to activation from a Th1 cell?

A

Increase production of cytokines: TNFα, IL-1 and -12

This induces production of antimicrobial agents: NO and O2-

Increased expression of MHC and costimulatory molecules

240
Q

How does the IL-17 produced by Th17 cells act indirectly to mobilise neutrophils?

A
  • Acts directly on non-immune cells and causes them to secrete chemokines
  • Chemokines attract and activate neutrophils
  • Neutrophils phagocytose and kill rapidly growing extracellular bacteria
241
Q

What does the IL-22 produced by Th17 cells do to epithelial cells?

A

Increases their integrity

242
Q

Which molecule is responsible for mediating neutrophil rolling?

A

Selectins

243
Q

How many types of CD8+ effector cells are there? List them

A

1

Cytotoxic T-lymphocyte

244
Q

Cytotoxic T-lymphocytes recognise and destroy infected cells by ____________ ___________

A

Cytotoxic T-lymphocytes recognise and destroy infected cells by inducing apoptosis

245
Q

Which MHC do CTLs recognise?

A

Class I MHC

246
Q

How do CTLs destroy infected cells?

A

The release cytotoxic granules towards the target cells that contains perforin and granzymes

247
Q

What does perforin (released by CTLs) do?

A

Perforin enables the granzymes to enter the target cell

248
Q

What do granzymes (released by CTLs) do?

A

Granzymes activate the target cells apoptotic pathways leading to cell death

249
Q

What type of MHC does B-cells recognise?

A

Trick question ;)

No MHC is needed, they recognise free antibodies

250
Q

What are activated B-cell called?

A

Plasma cells

251
Q

What are the 5 types of Antibody isotypes?

A

IgM

IgD

IgG

IgE

IgA

252
Q

How many types of antibody light chains are there?

A

2

λ and κ

253
Q

What is the funciton of IgD?

A

Receptor of naive B-cells

Not secreted

Function obscure

254
Q

What is the function of IgM?

A

Receptor of naive B-cells

Pentamer, hexamer

The first antibody secreted in the adaptive immune response

Low affinity

High avidity (10 antigen-binding sites!)

Best antibody at activating complement

255
Q

Which antibody has low affinity but high avidity?

A

IgM

256
Q

Which antibody is a pentamer?

A

IgM

257
Q

What is the function of IgA?

A

2 subclasses

Major antibody in mucosal surfaces

258
Q

Which antibody is a dimer?

A

IgA

259
Q

What is the function of IgG?

A

4 subclasses

Major serum antibody

Fixes complement

Opsonisation

Meonatal immunity

260
Q

What is teh function of IgE?

A

Specialised to fight helminths

Causes allergy

Interacts with mast cells, eosinophils and basophils

261
Q

In what ways do antibodies fight infectious disease?

A
  1. Nautralisation (only high affinity IgG and IgA)
  2. Opsonisation (IgG and IgA; also IgM via complement)
  3. Lysis (Only IgG and IgM)
262
Q

What antibody is secreted from plasma cells if there is no help from other immune cells?

A

IgM

263
Q

What antibody is secreted from plasma cells if there is T-cell help?

A

IgG

IgA

IgE

264
Q

What is the first type of antibody produced in response to infection?

A

IgM

265
Q

B-cells present antigens to T-cells on which type of MHC?

A

MHC II

266
Q

T-cells stimulate B-cells with _______ and ________

A

T-cells stimulate B-cells with CD40L and cytokines

267
Q

Which cytokine drives isotype switching to IgG?

A

IFNγ

268
Q

Which cytokine drives isotype switching to IgE?

A

IL-4

269
Q

Which cytokine drives isotype switching to IgA?

A

TGFβ

270
Q

Which PRR are important for recognising viral PAMPs?

A
  • Endosomal PRRs
    • TLR-3, -7 and -9
  • Cytoplasmic PRRs
    • E.g. Rig-like helicases
271
Q

Which type of IFN inhibits viral replicaiton?

A

Type I IFN

272
Q

What is the role of Type I interferons in acquired immunity?

A

Type I IFNs inhibit viral replication

Type I IFNs also acitvate dendritic cells and NK cells

273
Q

What do the activating and inhibitory receptors of NK cells recognise?

A

Activating receptors: stress ligands on infected cells

Inhibitory receptors: Class I MHC

274
Q

MHC class I presentation is particularly important for which pathogen type?

A

Viruses

275
Q

_____________ are the principal cellular effector mechanism in anti-viral immunity

A

Cytotoxic T-cells are the principal cellular effector mechanism in anti-viral immunity

276
Q

Which antibodies can block viral attachment and entry into cells?

A

IgA (mucosa)

IgG (blood)

277
Q

Once a virus has entered a host cell, which immune cells are needed?

A

CTLs and NK cells

278
Q

Which parts of the bacteria are commonly used as PAMPs?

A

Pili

Capsule

Cell wall

279
Q

Which cytokine promotes Th1 differentiation and cytotoxic activity in CTLs and NK cells?

A

IL-12

280
Q

What are some examples of bacteria that cause disease almost exclusively by the release of toxins?

A

Vibro cholerae

Corynebacterium diptheriae

Bordetella pertussis

Bacillus anthracis

281
Q

How does Uropathogenic E. coli (UPEC) causes disease?

A
  1. UPEC pili bind specifically to receptors expressed by the bladder epithelium
    • Type 1 pili (FimH at the pilin tip) to bind to specific mannose-containing glycoproteins in the urinary tract
  2. UPEC secrete toxins
  3. After binding UPEC invade bladder epithelial cells
    • FimH binds to integrins (an adhesion molecule)
282
Q

The type of immunity effective against bacteria will vary with bacterial pathogenesis. What is important for extracellular microbes?

A

Humoral immunity plus Th17 cells are important for extracellular microbes

283
Q

The type of immunity effective against bacteria will vary with bacterial pathogenesis. What is important for intracellular microbes?

A

Cellular immunity (Th1 cells and CTLs) are important for intracellular pathogens

284
Q

Which type of Th cells are important against obligate intracellular organisms?

A

Th1 responses are important against obligate intracellular organisms

285
Q

What changes induced in activated macrophages?

A
  • Increased production of cytokines:
    • TNF- , IL-1 (pro-inflammatory)
    • IL-12, IFN-(Th1 differentiation)
  • Production of antimicrobial agents such as lysosomal enzymes, NO, ROS
  • Increased expression of MHC and costimulatory molecules
286
Q

What type of immunity tends to be irrelevant for obligate intracellular organisms? Why?

A

Humoral immunity tends to be irrelevant for obligate intracellular organisms.

These organisms are rapidly phagocytosed via multiple receptors

Antibodies can’t penetrate cell membranes

287
Q

Which cells are of critical importance for extracellular bacteria? Why?

A

Th17 cells are of critical importance for extracellular bacteria

Th17 cells secrete IL-17

IL-17 leads to the production of proinflammatory cytokines and chemokines; which leads to a rapid influx of neutrophils

288
Q

Both ________ and ___________ are opsonins which can bind to the bacterial surface and make it more recognisable to phagocytes

A

Both complement and antibody are opsonins which can bind to the bacterial surface and make it more recognisable to phagocytes

289
Q

What can high affinity antibodies do in response to bacterial infection?

A

High affinity antibodies can neutralise bacterial toxins

High affinity antibodies can prevent bacterial colonisation

290
Q
A
291
Q

Comparing the innate and adaptive immune systems:

Select one:

a. Innate immune cells express many different Pattern Recognition Receptors, Adaptive immune cells express an antigen receptor of unique specificity
b. Innate immune cells are all generated in the bone marrow, adaptive immune cells are all generated in the thymus
c. Innate immune responses generate memory that is essential in vaccination
d. Adaptive immune cells kill pathogens as they are highly phagocytic

A

Comparing the innate and adaptive immune systems:

Select one:

a. Innate immune cells express many different Pattern Recognition Receptors, Adaptive immune cells express an antigen receptor of unique specificity

b. Innate immune cells are all generated in the bone marrow, adaptive immune cells are all generated in the thymus
c. Innate immune responses generate memory that is essential in vaccination
d. Adaptive immune cells kill pathogens as they are highly phagocytic

292
Q

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR
b. 3: HLA-DP, HLA-DQ, HLA-DR.
c. 1: HLA-class II
d. 4: HLA-A, HLA-B, HLA-C, HLA-D

A

How many alleles of classical MHC class II molecules does an activated human dendritic cell typically express?

Select one:

a. 6: 2 alleles of HLA-DP, 2 alleles of HLA-DQ, 2 alleles of HLA-DR

b. 3: HLA-DP, HLA-DQ, HLA-DR.
c. 1: HLA-class II
d. 4: HLA-A, HLA-B, HLA-C, HLA-D

293
Q

Which one of the following statements about IgG is true?

Select one:

a. It is a low avidity and high affinity antibody isotype.
b. Greater levels are found in serum in week one post-infection relative to week three.
c. It is the only isotype found on the surface of B cells.
d. It is a potent trigger of anaphylaxis

A

Which one of the following statements about IgG is true?

Select one:

a. It is a low avidity and high affinity antibody isotype.

b. Greater levels are found in serum in week one post-infection relative to week three.
c. It is the only isotype found on the surface of B cells.
d. It is a potent trigger of anaphylaxis

294
Q

Concerning B cell responses:

Select one:

a. The isotype first secreted by B cells is high affinity IgM
b. All B cell responses require T cell help
c. IFNg drives switching to some subclasses of IgG
d. Cytokine secretion by T cells is sufficient to drive isotype switching

A

Concerning B cell responses:

Select one:

a. The isotype first secreted by B cells is high affinity IgM
b. All B cell responses require T cell help

c. IFNg drives switching to some subclasses of IgG

d. Cytokine secretion by T cells is sufficient to drive isotype switching

BMS2052 (6 decks)

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