Brainscape's Knowledge GenomeTM

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


See full index

Immunology > Exam II > Flashcards

Exam II Flashcards

1
Q

what is antigen processing?

A

series of intracellular events in which antigen presenting cells make antigen available for T cells

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

Antigen processing involves

A
  1. Uptake of antigens (proteins)
  2. Degradation to peptides of MHC I or II
  3. Transport to the cell surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is antigen presentation?

A

Presentation of MHC peptide complexes on the cell surface for the stimulation of T cells

Typically done by antigen presnting cells (APC)
1. Dendritic cells
2. macrophages
3. B cells

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

Types of APC?

A

Dendritic Cells
Macrophages
B cells

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

T cell receptor binds to both

A

peptide and MHC molecule

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

T cells must have

A

MHC in order to be able to respond to an antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cytotoxic T cells

A

CD8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

CD8 complex consists of

A

alpha and beta

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

Helper T cell

A

CD4

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

CD8 T cell, their T cell receptor binds to

A

alpha3 domain of MHC class I

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

CD4 T Cell, their T cell receptor binds

A

Beta2 domain of MHC class II

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

Endocytic processing pathway

A

Exogenous (antigens from outside the cell) or MHC Class II processing pathway

Bound to MHC Class II and taken into the cell

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

Cytosolic

A

Endogenous (proteins that exist in the cytoplasm) or MHC Class I processing pathway

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

Endocytic Pathway

A
  1. Antigen is taken up from the extracellular space into intracellular vesicles
  2. In early endosomes of neutral pH, endosomal proteases are inactive
  3. Acidification of vesicles activates proteases to degrade antigen into peptide fragments
  4. Vesicles containing peptides fuse with vesicles containing MHC Class II molecules

The MCH class II binds to the peptide.

lower pH, more degradation

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

MHC II molecule is synthesized in

A

lumen of ER

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

How MHC class II gets to the processed peptides

A
  1. Invariant chains blocks binding of peptides to MHC class II molecules in the ER
  2. In vesicles, invariant chain is cleaved, leaving the CLIP fragment bound
  3. CLIP blocks binding of peptides to MHC Class II in vesicles
  4. HLA-DM facilitates release of CLIP, allowing peptides to bind
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

MHC Class II - endocytic

A

presents peptide antigens

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

Invariant chain - endocytic

A

directs class II away from secretory pathway to endocytic pathway and blocks peptide loading in the ER

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

HLA-DM -endocytic

A

acts as a chaperone or catalyst to facilitate exchange of CLIP with antigenic peptides

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

pH - endocytic

A

low pH and degradative environment facilitates denaturation of antigenic proteins

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

proteases - endocytic

A

cathepsins and other degradative enzymes chew up antigens into peptides

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

Cytoplasmic pathway (antigens are in the cytoplasm)

proteasome - degrades the antigen protein into peptides,

A
  1. class I is heavy chain is stabilized by calnexin until B2-microglobulin binds
  2. Calnexin is released and the heterodimer of class I heavy chain and b2m forms the peptife loading complex with calreticulin, tapasin, TAP, ERp57, PDI
  3. A peptide delivered by TAP binds to the class I heavy chain, forming the mature MHC class I molecule
    TAP (I and II)- transport port through the ER membrane.
  4. The class I molecule dissociates from the peptide loading complex and is exported from the endoplasmic reticulum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

MHC class I protein

A

alpha chain (3 domains) - transmembrane protein

beta 2 microglobulin - associated with all MHC 1 - stabilizes it.

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

peptides that are produced in the cytosol are transported into the ER

A

Peptides re generated in the cytoplasm and then transported through TAP into the ER and associate with MHC class I

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

MHC class I - cytosolic

A

presents antigenic peptides to T cells

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

proteasome - cytosolic

A

multi catalytic enzyme complex that degrades proteins into peptides

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

TAP - cytosolic

A

transport that shuttles peptides from cytosol to ER

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

peptide loading complex - cytosolic

A

calnexin, calreticulin, tapasin, Erp57: stabilize MHC class I and facilitate association with TAP to enable peptide loading

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

site where MHC II gets loaded with peptides

A

endosome

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

site where MHC I gets loaded with peptides

A

ER

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

Cytosolic pathogen

  • Degraded in:
  • peptides bind to:
  • Presented to:
  • Effect on presenting cell
A

Degraded in - cytosol

Peptides bind to - MHC I

Presented to - effector CD8 T cells

Effect on presenting cell - cell death

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

Intravesicular pathogens

Degraded in:
- peptides bind to:
- Presented to:
- Effect on presenting cell

A

Degraded in: endocytic vesicle (low pH)

Peptides bind to: MHC class II

Presented to: Effector CD4 T cell

Effect on presenting cell: Activation to kill intravesicular bacteria and parasites

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

How T cell receptors bind to MHC

A

They do directly bind to MHC molecule -> Polymorphic reside of MHC and T cell contact reside of peptide

But

they also have direct contain with the peptide bound to MHC. T cell contact reside of peptide

  • “pocket of MHC”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Major histocompatability complex (MCH)

A

refers to the complex of genes that encode molecules on the cell surface that:

  1. mediate T cell reactivity to pathogen infection -> present peptides derived from pathogens to T cells)
  2. Compatability of organ transplants
  3. susceptibility to certain autoimmune diseases

Known as HLA in humans and H-2 in mice

divided into three groups: MHC class I, II and III

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

HLA

A

Human Leukocyte Antigen

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

MHC class I structure

A

Peptide binding cleft: alpha 1+ alpha 2
1 Transmembrane domain
Associates with beta2Microglobulin (always)
CD8 binds to alpha3

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

MHC class II structure

A

Peptide binding cleft: alpha 1+ beta 1
alpha 2 and beta 2 are distal from the binding cleft

2 transmembrane regions

CD4 binds to beta 2 domain.

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

Difference in structure of MHC I and II

A

I - beta chain is not a transmembrane protein
II - beta chain is a transmembrane protein

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

Both MHC I and II consists of a

A

base of beta pleated sheets

and walls are formed of 2 alpha helices.

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

MHC class I - restricted

A

strict binding site, allows peptides of 8-10 aa in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

MHC class II - flexible

A

flexible peptide binding site allows peptides of 10-24+ aa in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Where is the variablility?

A

MHC I - peptide binding cleft on both beta pleated sheets and alpha helices

MHC II - majority is in the beta chain. both alpha helix and beta pleated sheets

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

MHC is both

A

polymorphic - every gene locus, more than one allele

polygeny - many different MHC molecules/genes expressed

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

genetic polymorphism

A

variants or alternative forms of a gene present in a population at a stable frequency

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

allele

A

one type of variant

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

homozygous

A

having two identical alleles of the same gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

heterozygous

A

having two distinct alleles of the same gene

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

haplotype

A

the collective set of MHC alleles present on an individual chromosome

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

Human types of MHC class I isotypes

Highly polymorphic

A

HLA - A
HLA - B
HLA - C

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

Human MHC Class II isotypes

Polymorphic

A

HLA - DP
HLA - DQ
HLA - DR (Oligomorphic + highly polymorphic)

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

Which HLA is the most polymorphic

A

HLA-B

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

Which MHC class is most selective?

A

MHC class II

BCells, macrophages, dendritic cells only. but these cells are also expressed by class I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

MHC Class I expressed by every cell except

A

erythrocytes

54
Q

MHC Class I overview

A

expressed by “all cells”
expression constitutive, but can be up-regulated by Type I interferon ( alpha or beta)

55
Q

MHC class II overview

A

expressed by antigen presenting cells: B cells, DC, macrophages – Can be upregulated on these cell types by IFN-gamma / type II interferon

expression inducible above basal levels: interferon gamma and CIITA ( transcription factor)

56
Q

CIITA

A

transcription factor that upregulates the expression of MHC Class II

57
Q

MHC genes are expressed

A

co-dominantely

58
Q

constitutive -> Immunoproteasome

A

constitutive proteasome ( 19S cap + beta chains)

IFN -gamma initiates exchange of beta subunits —improves generation of peptides that bind to MHC class I

immunoproteasome - (PA28 cap + new subunits)

59
Q

exchange of beta subunits

A

improves generation of peptides that bind MHC class I

Different caps - speeds up export of peptides

60
Q

complement induces

A

inflammation -> initiates adaptive immune response

61
Q

inflammation awakens adaptive immunity through DC

A

DC are the sentinels if the immune system, communicating between the innate and adaptive immune system

DC at the sites of infection become triggered to “mature” in response to PAMPs or inflammation

DC migrate through lymphatics to draining lymph nodes interacting with many T and B cells

Maturation of DC greatly enhances their ability to stimulate B and T cells

62
Q

Immature dendritic cells

A

Tissue resident, resting

Highly endocytic, phagocytic

low level expression of costimulatory molecules

poor stimulators of T cells

63
Q

Mature dendritic cells

A

homes to lymph node

endocytosis shut down

high level expression of costimulatory molecules and cytokines

highly stimulatory for T cells

64
Q

Mature dendritic cells

A

homes to lymph node

endocytosis shut down

high level expression of costimulatory molecules and cytokines

highly stimulatory for T cells

65
Q

local infection, innate immunity ->

A

dendritic cells take infection to lymph node and stimulates adaptive immune system (T cells)

66
Q

The lymph node

A

T and B cells have different regions in the lymph nodes

67
Q

B cell zone

A

lympohoid follicle
germinal center - clonal expansion

68
Q

primary lymphoid organs

A

bone marrow
thymus

sites where B or T cells undergo selection and development

69
Q

secondary lymphoid organs

A

spleen
lymph nodes

sites where B or T cells undergo activation

70
Q

primary lymphoid organs

A

Bone marrow and thymus

sites where leukocytes undergo hematopoiesis (development and differentiation). Houses naive leukocytes

71
Q

Secondary lymphoid organs

A

all other lymphoid organs, spleen and lymph nodes. sites at which naive, activated and memory cells are housed.

72
Q

B cell receptor

A

expressed on surface (named B cell receptor) or secreted (antibody)

2 identical heavy chains + 2 identical light chains

2 antigen binding sites. -> each consists of a variable light chain region + variable heavy chain region.

73
Q

B cell receptor

A

expressed on surface (named B cell receptor) or secreted (antibody)

2 antigen binding sites (most variable).

74
Q

Life stages of B and T cells

A
  1. Generating a receptor
  2. Selection
  3. Activation
  4. Differentiation
75
Q

generating a receptor

A

rearrangement

76
Q

selection

A

making sure the receptor does not react with self

77
Q

activation

A

providing all of the signals needed to cause clonal expansion

78
Q

Differentation

A

signals received during activation dictate the differentiation of the cells and its specific function

79
Q

T and B cell receptors are the products of

A

gene rearrangement (somatic)

every cell line has same germ-line configuration, except for B and T cells

80
Q

after rearrangement T and B cells

A

no longer have the germline configuration. however, they did before rearrangement

81
Q

memory cause

A

long term changes in repertoire

82
Q

Each lymphocyte bears

A

a single type of receptor with a unique specificity

83
Q

interaction between a foreign molecule and

A

a lymphocyte receptor capable of binding that molecule with high affinity leads ro lymphocyte activation

84
Q

the differentiated effector cells derived from an activated lymphocyte will bear receptors of

A

identical specificity to those of the parental cell from which that lymphocyte was derived

85
Q

lymphocytes bearing receptors specific for ubiquitous self molecules

A

are deleted at an early stage in lymphoid cell development and are therefore absent from the repertoire of mature lymphocytes

86
Q

B cells “see”

A

native antigen through BCR

87
Q

T cells “see”

A

antigenic peptides (digested or processed pieces of antigens) presented by MHC molecules

88
Q

specific antibody are good for

A

neutralization and opsonization

89
Q

B cells can both be

A

expressed on the cell surface, but after activation, B cells may be secreted

90
Q

antibody function is critical for viral or bacterial infection

A

first line of defense at mucosal sites; critical in limiting the dissemination of pathogen in secondary infection (and following vaccination)

91
Q

autoimmunity

A

anti-DNA antibodies have been detected in patients with autoimmune syndromes

92
Q

research

A

critical for assays such as western blots, ELISAs, flow cytometry and immunohistochemistry

93
Q

clinically

A

cancer therapy (non-Hodgkin’s lymphoma) and autoimmunity (rheumatoid arthritits)

94
Q

immunoglobin

A

Secreted form of B cell receptor

composed of two heavy chains (50KDa) and two light chains ( 25KDa)

the two heavy chains are identical as are the two light chains

there are multiple disulfide bonds, both intra and interchain

contains discrete antigen binding regions in the N terminus from both the heavy and light chains. Binding region consists of one region from the heavy chain and one region from the light chain

Fc portion - bottom part of the heavy chains

95
Q

heavy chain consists of

A

one variable regions
several constant regions - changes between different isotypes

96
Q

variable region of the heavy chain is

A

the part that forms the antigen binding site and can vary

97
Q

light chain consist of

A

one variable region, and one constant

98
Q

Fc region

A

fraction crystalize

Formed by two constant heavy chains

they do not change (no rearrangement)

99
Q

Fab region

A

Fragment antigen binding

variable + constant constant of both heavy and light chains (all of light chains)

100
Q

antibody structure

A

allows for flexibility and binding to a range of antigens

101
Q

determines the antibody isotype

A

Fc region

102
Q

B cell receptor cytoplasmic tails

A

very little …

must co-reside with signaling molecules in the membrane known as IgBeta and IgAlpha

103
Q

IgBeta + IgAlpha

A

provide the longer cytoplasmic tail needed by B cell receptors to bind with kinases and to initiate signaling cascades and phosphorylation

if there is no IgBeta and IgAlpha - the B cell receptor cannot be expressed on the surface

104
Q

CDRs ( complementarily determining regions)

A

“fingers” sticking out of the VH and VL region of the antigen binding site

105
Q

Each antigen may be contacted by

A

6 hyper-variable loops, 3 in the light chain, 3 in the heavy chain

most of the diversity between antibodies is in these regions

106
Q

the most diversity is observed in the complementary determining region

A

CDR3 (most likely to make contact with the antigen because it is located outside)

The highest number of Ab:Ag contacts are usually with the CDR3 region

107
Q

conformational determinant

A

if an antibody is folded in its native form and it is then heated or chemically treated, the antibody will lose its form by denaturation

the epitope would be unwound and not able to bind to that same receptor

108
Q

linear determinant

A

Ig binds to determinant in both native and denatured protein - not sensitive

Ig binds to determinant in denatured protein only - not to the native form of the protein

109
Q

five major types of isotypes of human antibodies - no difference in the antigen binding sites. The Fc portion is what changes between the different isotypes

A

IgG
IgM
IgD
IgA
IgE

110
Q

IgM

A

first expressed isotype + first one to be secreted.

But through the lifetime of a B cell, it may express many of the isotypes

111
Q

IgM + IgA = can be expressed as a monomer or multimer

A

when IgM binds to J-chain, it is expressed as a pentameric IgM.

112
Q

IgA can be expressed as a

A

dimer, when it binds to the J-Chain

113
Q

Valency and Avidity of antigen-antibody interactions

A

Valency of interaction ( monovalent, bivalent, polyvalent - essentially how many binding sites of the antibody is occupied by the antigen)

Avidity - the collective affinity of an interaction.

Ex:
valence of interaction: monovalent -> avidity of interaction:low

Valence of interaction: polyvalent -> avidity of interaction: very high

114
Q

IgM function

A

Mostly activation of complement

+IgG

115
Q

IgG function

A

Neutralization
Opsonization
Sensation for killing by NK cells
Complement activation
Transport across placenta
Diffuse into extravascular sites

116
Q

IgA function

A

Neutralization
Transport across epithelium

117
Q

IgE function

A

Sensitization of Mast cells
Sensitization of Basophils

118
Q

IgA Isotype function

A

transport across mucosa, neutralizatio n

119
Q

IgD isotype function

A

antigen receptor on naive B cells, Sensitizes Basophils

120
Q

IgE Isotype function

A

immediate hypersensitivity, sensitizes Mast Cells

121
Q

IgG Isotype function

A

Neutralization, opsonization, complement activation, neonatal immunity (crosses placenta)

122
Q

IgM isotype function

A

antigen receptor on naive B cells, complement activation

123
Q

How to generate monoclonal antibodies

A

Isolate spleen cells from mouse immunized with antigen X

Mixture of spleen cells including some producing anti-X-antibody (B cells) fusing with myeloma cells (tumor cells)

HAT medium - allows for killing of myeloma cells and B cells that had not fused

Selective group of hybridomas (fused version of B and myeloma cells)

Grow the cell that has the highest affinity -> hybridomas producing monoclonal anti-X-antibody

124
Q

Flow cytometry

A

good for measuring antibody labeled cells

125
Q

monoclonal cells originally was developed from

A

mouse cells

126
Q

Four types of therapeutic monoclonal antibody

A

mouse
chimeric
humanized
human

127
Q

antibodies as drugs in Rheumatoid Arthritis

A

Anti-TNF monoclonal antibodies
TNF receptors

128
Q

combinatorial diversity

A

multiple germ line gene segments

129
Q

Heavy chain locus

A

V, D, J regions

130
Q

Light chain locus

A

V, J regions

131
Q

Heavy chain event (first)

A

Germline DNA

  • somatic recombination

DJ joined DNA

  • somatic recombination

VDJ-joined rearranged DNA - these attach to a constant region

132
Q

Light chain event

A

Germline DNA

  • somatic recombination

VJ joined rearranged DNA - then attaches to a constant region

Immunology (18 decks)

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