Immunology Flashcards
1
Q
receptors of macrophage
A
TLR
Mannose R
CR R
Fc R
C3a and C5a R
2
Q
receptors of neutrophil
A
TLR
CR R
Fc R
C3a and C5a R
3
Q
receptors of basophil
A
IgE R
4
Q
receptors of mast cell
A
IgE R
C3a and C5a R
5
Q
receptors of NK cell
A
MICA stress R
MHC I R
Fc R
6
Q
receptors of dendritic cell
A
TLR
Mannose R
7
Q
cytokines produced by macrophages
A
TNF-alpha
IL6
IL1
CXCL8
IL12.
8
Q
cytokines produced by neutrophil
A
TNF-alpha
9
Q
cytokines produced by eosinophil
A
prostaglandins
unspecific cytokines
10
Q
cytokines produced by basophil
A
histamine IL4
11
Q
cytokines produced by mast cell
A
histamine
12
Q
cytokines produced by NK cell
A
IFN-gamma
perforin
granzymes
13
Q
cytokines produced by dendritic cell
A
Co-stimulatory proteins
TNF-alpha
IL6 IL1
IL12
IFN-alpha
14
Q
Functions of macrophages
A
phagocytosis
inflammation
T-cell activation
tissue repair
15
Q
functions of neutrophil
A
phagocytosis
inflammation
16
Q
functions of eosinophil
A
parasitic defense
phagocytosis
allergies
inflammation
17
Q
functions of basophil
A
inflammation
parasitic defense
allergies
18
Q
functions of mast cell
A
inflammation
19
Q
functions of NK cell
A
viral control
tumour apoptosis
20
Q
Ways in which macrophage work
A
form phagolysosome
APC
21
Q
Ways in which neutrophils work
A
- form phagolysosme (oxygen independent and dependent)
- form NET (neutrophil extracellular trap):
- – toxic granules
- – chromatin
22
Q
Ways in which eosinophils work
A
kill large parasites (by highly toxic granules and ROS)
cause inflammation (prostaglandins and cytokines)
levels increase when TH2 secretes IL5
23
Q
ways in which basophils work
A
promote TH2 development
24
Q
ways in which mast cells work
A
C3a and C5a cause histamine release
25
ways in which NK cells work
Apoptosis (by perforin and grazymes) when:
-- Increased stress receptor
-- Decreased MHC i
-- Cell coated in antibody
26
ways in which dendritic cells work
form phagolysosome
activated further by IFN-alpha and IFN-beta
Moves (via chemokine gradient) to the nearest lymph node to activate T lymphocytes
27
what does TNF-alpha do?
enhances endothelium permeability
expression of adhesion molecules
inflammation
28
what does IL6 do
* makes liver produce acute-phase proteins
* -c reacitve protein
* -mannose binding lectin
* fever
* TH17 differentiation
* TFH differentiation
29
what does IL1 do
fever
30
what does CXCL8 do
recruits neutrophils from bloodstream
31
what does IL12 do
activates NK cells causes production of TH1 cells
32
What does IFN-gamma do
activates macrophages
TH1 differentiation
Suppersses TH2
Increases MHC processing
IgG1 and IgG3 production
33
what does IFN-alpha do
activates NK cells
activates dendritic cells
increases MHC I production
34
what does IFN-beta do
activates dendritic cells
35
what does IL2 do
helps promote cytotoxic t cell proliferation
36
What does c reactive protein do
acts as opsonin on microbes activates classical complement
37
what does mannose binding lectin do
activates mannose binding complement pathway
38
what does ferritin do
binds iron - inhibits microbe iron uptake
39
what does fibrinogen do
causes coagulation
40
what does factor VIII do
causes coagulation
41
what does serum amyloid A do
recruitment of immune cells to inflammatory sites
42
steps of ADCC. What does ADCC stand for?
stands for Antibodhy dependent cellular cytotoxicity)
1: antibody binds antigens
2: Fc R on immune cells recognise antibody
3: cross-linking of Fc R signals immune cell to kill antigen
4: cell dies by apoptosis
43
Describe the steps of inflammation
1- tissue injury
2- release of chemical signals (eg. histamine)
3- dilation of vessels and increased permeability of vessels
4- migration of phagocytes to area
44
What causes pain when you have inflammation
released mediators such as
1. TNF-alpha
2. Bradykinin
3. Histamine
STIMULATE NERVE ENDINGS
45
What are the functions of inflammation
1- prevents spread of damaging agents
2- phagocytosis (eg. cell debris and pathogens)
3- alerts adaptive immune system
4- sets stage for tissue repair
46
What are the primary lymphoid organs
bone marrow
thymus
47
What immune cells does the bone marrow produce
myeloid cells
NK cells
B and T lymphocytes
48
Where do T lymphocytes complete development
in the thymus
49
what initiates extravasion
chemokines and expression of adhesion molecules on endothelial cells
50
what causes endothelial cells to express cell adhesion moleulces
TNF-alpha and C5a
51
what is the main cell adhesion molecule used in extravasion
P selectin
52
What are chemokines
molecules that form chemotactic gradient that directs leukocytes to site of infection
53
What are the five steps of extravasion
rolling adhesion
tight adhesion
transmigration
breakdown of basement membrane
Cells follow chemokine gradient
54
What causes rolling adhesion in the extravasion process
Carbohydrate ligands (on pathogen) bind to P selectin molecules
55
What causes tight adhesion in the extravasion process
IFA integrins on leukocytes are activated by (inside-out) chemokine signalling
Bind to ICAM Receptors on endothelial cells tightly
Stop rolling
56
What causes transmigration in the extravasion process
PECAM proteins present on leukocytes and on junctions between endothelial cells
Enables leukocytes to move through the gap
57
What causes the break down of the basement membrane in the extravasion process
MMP. It is an enzyme produced by leukocytes.
58
What are the physical barriers in the immune response
MECHANICAL BARRIERS
Mucous secretion and ciliated tract
Secretion of tears
Flushing action of urine
BIOCHEMICAL FACTORS
Lysozyme in tears
HCl of stomach
MICROBIAL FACTORS
Commensal bacteria
59
What do CR receptors do
Complement receptors Recognise 3b
60
What do Fc receptors do
Receptor of Fc (constant region) of antibody
61
What are the receptors to recognise PAMP (pathogen-associated moecular pattern)
TLR 1 (TLR6=heterodimer): Peptidoglycan
TLR4: LPS
TLR5: Flagellin
TLR 3 (Intracellular): dsRNA
62
Explain the process of phagocytosis
- phagocyte binds via receptor
- gets engulfed
- forms phagosome fuses with lysosome
- phagolysosome gets destroyed via an oxygen-dependent or oxygen-independent pathway
63
Describe the process of oxygen-independent phagocytosis
Lysosome and basic proteins
64
What activates the complement proteins
Cutting of complement proteins into fragments
65
What are the main complement chemo-attractants
C3a and C5a
66
What are the main complement opsonins
C3b
67
What forms the MAC
C5b6789999
68
What are the functions of effector CD4 T cells
activate dendritic cells to increase activation of CD8 T cells (cause production of B7)
Increase activation of macrophages that present peptides on MHC II
Activate B cells to become plasma cells that present peptides on MHC II
69
What are examples of mucosa-associated lympoid tissue
Tonsils
Peyers patches
appendix
70
What determines the function of an antibody
the constant region
71
What causes production of acute phase proteins
IL1 and IL6 which stimulate the liver to produce acute phase proteins
72
Explain inflammation caused by the complement
C3a and C5a
Chemo-attraction recruits cells
Release of histamine by mast cells
Increase permeability by endothelial cells
73
Explain the classical complement pathway
74
Explain the lectin pathway
75
Explain the alternate pathway
76
How does a mature dendritic cell activate a T cell
77
How does a CD8 cell kill an infected cell
78
How does a T cell activate a macrophage
79
How does a T cell activate a B cell
Sends survival signals
80
What two chains does a MHC I consist of
Beta2 microglobin
alpha chain
81
What encodes MHC
HLA (Human Leukocyte Antigen)
82
How many amino acids is each peptide attached to MHC I
8-10
83
Explain antigen processing in a cell expressing MHC I
1. Viral proteins degraded by LMP Proteasome -- 8-10 amino acids in length
2. TAP1 and TAP2 (Transporters associated with antigen processing) translocate peptides from cytosol to ER lumen
3. MHC I helped by chaperon eproteins due to it being unstable until it binds to protein
4. MHC I moves through ER, attaches protein, moves through golgi and gets packaged into vesicle to be expressed on surface
84
What are the kinds of MHC I that each person has
_A maternal and paternal version of:_
HLA-A
HLA-B
HLA-C
85
What type of MHC is associated with Ankylosing Spondylitis
HLA-B27
86
What type of MHC is associated with recovery from lethal malaria
HLA-B53
87
What two protein chains are associated with MHC II? What forms the peptide binding cleft
alpha and beta chains
alpha-1 and beta-1 form the peptide binding cleft
88
What are the types of MHC II in humans
_Materal and Paternal copies of:_
HLA-DP
HLA-DQ
HLA-DR
89
How many amino acids does each MHC II bind
Bind peptides of 13-17 amino acids in length
90
What is different between the way that MHC I binds peptides and the way that MHC II binds peptides
MHC I - attached at one site
MHC II - attached along entire length
91
Explain the antigen processing in MHC II
1. MHC II is made on ER
2. Invarient chain binds to prevent cytoplasmic peptide binding and travels to endosome in vesicle
3. Acid proteases cleave invarient chain. Leaves CLIP blocking the peptide groove
4. Protein HLA-DM swops CLIP for pathogen peptides
5. Packaged into vesicle
6. Expressed on cell membrane
92
Which MHC is associated with Coeliac disease? What is coeliac disease?
HLA-DQ2 and HLA-DQ8
Coeliac disease is Gluten Sensitive Enteropathy
93
What is the structure of a TCR
94
What type of recombination does an alpha chain undergo (of a T cell)
V-J recombination
95
What type of recombination does a beta chain undergo (of a T cell)
V-D-J recombination
96
What enables TCR diversity
* Ingeritence of multiple germline genes
* somatic recombination
* Junctional diversity: imprescise joining and insertion of small sets of nucleotides at the junctions
* Random selection of alpha and beta chains
97
Explain the process of positive selection
1. MHC I and MHC II come into contact with developing T cells (thymocytes)
2. CD4 == MHC I. CD8 == MHC II
3. If they don't bind, they die by neglect
98
Explain the process of negative selection
1. Rare pepulation of thymic cells generally expressed outside the thymus make AIRE (autoimmune regulator) which is:
1. Transcription factor
2. Enables expression of proteins which are only produced in specific cells (E.g. insulin)
2. If a thymocyte binds too strongly to this, they die by apoptosis
99
Where does positive selection of T cells happen
In the cortex of the thymus
100
Where does negative selection of T Cells happen
In the medulla of the Thymus
101
What do effector CD4 cells secrete
IL12 -- promotes CD8 cell proliferation
102
What cytokines do CD8 T cells secrete
IL2
103
How does the extrinsic pathway of the CD8 T cell work
FAS ligand binds to FAS
104
How does the intrinsic pathway of the CD8 T cell work
Perforin and Granzyme are secreted which cause apoptosis of the antigen
105
What determines the differentiation of a CD4 T cell?
What are the associated cytokines with each CD4 T cell?
What kind of cytokines are present when it is differentiating
* IFN-gamma + IL12 = TH1
* IL4 = TH2
* TGF-beta + IL6 = TH17
* IL6 = TFH
* TGF-beta + IL2 = TReg
106
What cytokine does TH1 secrete
IFN-gamma (activates macrophages)
107
What does TH1 activate? How does it do this?
Macrophages
Via a CD40 + CD40-L synapse
108
What is the main role of TH1
to destroy microbes that persist in macrophage vesicles
109
What cytokines do TH2 secrete
IL4 and IL5
These recruit granulocytes
110
what is the main function of TH2
to destroy extracellular parasites
111
What happens if TH2 is activated inappropriately?
Allergies in most cases
112
What is the first effector helper cell to be generated in the presence of IL6 and TGF-beta
TH17
113
What cytokine does TH17 secrete? What is its function?
IL17
Causes fibroblasts and epithelial cells to secrete IL6, CXCL8, G-CSF
114
What is the main role of TH17
amplifies the acute inflammatory response by the innate emmune system. It's main role is to recruit neutrophils important in fighting extracellular bacteria and fungi.
115
Where are TFH located?
Stay in the follicles of secondary lumphoid organs (lymph nodes and spleen)
116
What cytokines do TFH secrete
IFN-gamma
IL4
TGF-beta
117
What is the main role of TFH
to activate B cells:
* To somatic hypermutate the variable region
* To class switch to produce new antibodies
* To become plasma cells
118
How does TFH activate B cells
Makes a CD40 + CD40-L immunological synapse
119
In the presence of \_\_\_, B cells produce \_\_\_
1. IFN-gamma; IgG1 and IgG3
2. IL4; IgE
3. TGF-beta; IgA
120
What enables memory T cells to block the apoptotic death of some lymphocytes
Expression of BCL2
121
What are the two types of Tregs
Natural Tregs
Adaptive Tregs
122
Where do natural tregs develop
thymus
123
What do natural tregs secrete
IL10 and TGF-beta
Inhibit T cell proliferation. Prevents dendritic cell from secreting IL12, thus preventing CD4 differentiation into TH1
124
Where do adaptive tregs develop
in the periphery
125
What do adaptive tregs secrete
IL10
IL4
TGF-beta
126
What does a lack of adaptive tregs result in
autoimmune disease in gut
inflammatory bowel disease
127
Where do B cells develop? Where is its receptor made
In the bone marrow
128
Describe a BCR
2 heavy and 2 light chains
Heavy chains: variable and constant region
Light chains: variable and constant region
Disulphide bonds join them
129
Explain the recombination of the B cell heavy chain
V-D-J recombination
Variable region is attached to the first constant region mu.
If mRNA is produced and cannot be translated into functional protein, other chromosome is recombined instead.
130
Explain the recomination of the B cell light chain
V-J recombination
Two gene coding loci:
* Kappa (attempted first) --- 2x as many
* Lambda
131
Explain the process of negative selection of BCR
If BCR binds too strongly to antigen - undergoes apoptosis
132
Where does a naive B cell recieve its survival signals from?
From the lymph node when it is circulating
133
How long does a naive B cell survive
3 days
134
Where in the lymph node is a B cell found
In the primary lymphoid follicle
135
Explain the process of activation of a B cell
* BCR binds to antigen on Follicular Dendritic Cell and presents them on MHC II after endocytosing antigen.
* TFH cell recognises peptide and activates B cell
* Some B cells are activated to proliferate and become plasma cells that secrete IgM
* Class switching and Somatic hypermutation happen due to the TFH binding
136
What are the factors that lead to diversity of the BCR repertoire
1. Combined Diversity (VDJ)
2. Junctional diversity (addition of nucleotides)
3. Combination of heavy and light chain
4. Somatic hypermutation
137
How does class switching occur
1. Change in the constant region of the heavy chain in a gene. This requires preceding constant regions to be removed as first is always selected. This results in excised DNA segment
2. Results in a different antibody
THE ANTIBODY IS DETERMINED BY THE CYTOKINES THAT ARE PRESENT
138
What is the variable region of an antibody also called
Fab (Fragment antibody binding)
139
What is the constant region of an antibody also called?
Fc (Fragment constant)
140
What are the different antibody constant regions? What isotype/class do they produce?
mu = IgM
delta - IgD
gamma = IgG
epsilon = IgE
alpha = IgA
141
What is the structure of IgM
Pentamer == 4 constant regions
142
How long does an IgM last
5 days
143
What is the structure of an IgG
Monomer == 3 constant domains
144
What is the function of IgG
Fixes complement
145
Which cells recognise IgG
macrophages, neutrophils and dendritic cells
146
How long does IgG last
23 days
147
What is the structure of IgA
Dimer == 3 constant regions
148
What is the function of IgA
Primarily acts as a neutralising agent
149
How long does IgA last
6 days
150
How does IgA get into the hollows of organs
Secreted by plasma cells in MALT
Binds to receptor and is internalised
Carried through cytoplasm of epithelial cell to lumen
Cleaved enzymatically at lunial surface which results in the release of IgA with part of receptor (secretory component) attached
151
What is the structure of IgE
Monomer
152
What is the function of IgE? How does it work?
Binds to FC-epsilon-R on mast cell and eosinophil
Remains on surface of mast cells, waiting for second exposure to antibody.
If an antibody binds a large mulivalent pathogen again, IgE is cross-linked on mast cell surface which results in degranulisation
153
How long does IgE last
6 hours
154
Which antibody is important in allergies
IgE
155
What does JAK-STAT signalling regulate
Cellular responses to cytokines and clood cell growth factors (poeitins):
haemopoeisis
Immune development
Immune activation
156
What results from the dysregulation of JAK-STAT signalling
Inflammatroy disease
Erythrocytosis
Immune deficiency
Leukaemias and Myeloproliferative disorders
157
Explain the process of JAK-STAT signalling
1. Cytokine binds to tyrosine receptor and causes it to dimerise
2. JAK (on the tyrosine receptor) phosphorylates the tyrosine receptor. This causes it to attract STAT
3. JAK phosphorylates STAT which then leaves the receptor
4. STAT dimerises, enters nucleus and acts as a transcription factor
158
What are the types of cytokines that are most commonly used in JAK-STAT signalling
IL2, IFN-gamma, Erythropoeitin, GH
159
Explain the process of TCR Signalling
1. TCR + CD4 complex binds to MHC II
2. LCK (tyrosine kinase) phosphoryates part of the TCR
3. The phosphorylated TCR results in activation of ZAP-70 (tyrosine kinase)
4. ZAP-70 phosphorylates LAT and SLP-76 (both scaffold proteins)
5. Scaffold proteins are held together by GADs (adaptor proteins). Phosphorylation of the scaffold proteins results in activation of PLC-gamma (phospholipase C)
6. Remain steps follow that of the Gq signalling pathway
160
Explain the process of BCR signalling
BCRs are cross-linked by an antigen
This stimulates SRC Tyrosine Kinases inside of the cell to be activated
161
What is a NF-kappa-B
A transcription factor
162
What does NF-kappa-B simulate the production of
cytokines
acute phase proteins
apoptotic regulators
163
Explain the NF-kappa-B family
Class
Protein
Aliases
I
NF-kappa-B1
P105 – P50
NF-kappa-B2
P100 – p52
II
Rel A
P65
Rel B
C-Rel
164
Explain the significance of having Class I and Class II NF-kappa-B. Also explain the difference thereof.
Class I need to be bound to class II
Class I: large precursors are converted into mature proteins (by degradation of the C terminal)
Class II are ready to activate the gene due to having TAD (Transactivation domain)
Class I has no TAD. Results in suppression of gene unless bound to Class II
165
What are the parts of NF-kappa-B that binds to DNA
N-terminal Rel homologous domain
166
What are cytokines and receptors that work together to activate the NF-kappa-B
TNF-alpha via TNFR
IL1 VIA IL1 R.
BCR and TCR also activate pathways
167
Explain the process of NF-kappa-B signalling
* I-kappa-B naturally inhibits dimerisation of the pathway
* IKK-beta is in a complex with IKK-alpha and NEMO
1. Cytokine binds to a Receptor
2. TAK1 gets activated, through adaptor proteins, by the TNF Receptor
3. TAK1 phosphorylates IKK-beta and activates it
4. This phosphorylated IKK-beta phosphorylates I-kappa-B with tags it for polyubiquination
5. Heterodimer is now able to form
168
What are the different receptors used in NK-kappa-B signalling? What are their functions?
BCR/TCR --\> Adaptive immune response
TLR --\> Innate immune response
TNF-beta and IL-1R1 --\> Inflammatory response
169
What are the diseases that have an effect on the NF-kappa-B pathway? What do they do?
* Viruses
* HIV Proteins
* Binding sites for NF-kappa-B controls expression of the viral gene
* Yersina Pestis (causes plague)
* Secretes YopP that prevents ubiquination of I-kappa-B which causes blockage of the person's immune response
* Cancers
* Inappropriate activation of NF-kappa-B
* Inflammatory diseases
* Exploit this pathway
170
Regarding monoclonal antibodies, what can be conjugated to them
Fluorochromes and Enzymes
171
What are examples of in-vitro diagnostic agents
ELISA
Flow Cytometry
Immunohistochemistry
Western Blotting
172
Explain the process of Indirect ELISA
Detects antibody in serum
1. The well is coated with antigen
2. Serum is added and the antibodies bind
3. Well is washed and antibodies are added that are anti-human
4. Washed again and a substrate is added that changes colour
173
What is the major difference between Direct and Indirect ELISA
Indirect ELISA - Detects antibody in serum
Direct ELISA - Detects antigen in serum
174
What are the properties that can be tested for using flow cytrometry
Particle/cell size (forward scatter - a shadow)
Particle/cell complexity (side scatter - granules, nuclear lobes)
Surface or intracellular markers (fluorochromes linked to MoAB)
175
In flow cytrometry, what are the antigens that are targetted by fluorochrome labelled monoclonal antibodies
B-cells --\> CD19, CD20, CD22
T-cells --\> CD3, CD4, CD8
Myeloid Cells --\> CD13, CD33
176
What are all the things required for cell cytrometry?
1. Cells need to be in single file.
1. In sheath fluid (a special solution)
2. Hydrodynamic focusing: Uses energy to focus small particles to centre
2. Laser
3. Optics --\> mirrors and Filters
4. Electronic detection system
5. Computer software
177
What do you use to sample and identify components of a solid tumour
Immunohistochemistry
Stain with monoclonal antibodies with associated colour change
178
Explain the process of western blotting
1. Separate proteins using gel elctrophoresis
2. Stain separated proteins with antibodies to see which ones they are
(helps in detection of HIV)
179
What is the difference between monoclonal and polyclonal antibodies
Polyclonal = Many antibodies that are different that recognise the same antigen
Monoclonal = Antibodies that are identical (come from same B cell)
180
How are monoclonal antibodies produced using mice
1. Mouse injected with antigen
2. Reinject mouse later to get a greater secondary immune response
3. Take lymph nodes and spleen and put into tube to get B lymphocytes
4. Add myeloma cells:
1. live long
2. some form hybridomas with B lymphocytes
5. Need to select for hybridoma cells
181
Explain the selection for hybridomas
* B cells
* short-lived and die in a few days
* Myeloma cells
* no enzymes for salvage pathway
* De Novo pathway blocked
* Screening and purication of most appropriate antibodies from the most appropriate hybridome
* You need one type of hybridoma in one plating well in order to select hybridoma secreting correct antibody
182
Explain the selection of Fab (variable region) using bacteriophages in creating monoclonal antibodies
1. Isolate populations of genes encoding antibody variable regions
2. Construct fusion protein of V region with a bacteriophage coat protein
3. Cloning a random population of variable region gives rise to a phage-display library
4. Selection of phage with desired V region occurs by specific binding of antibody to antigen
183
What are the examples of drugs that use monoclonal antibodies? What do they do?
Trastuzumab: Inhibits growth factor receptor found on surface of some breast cancer cells
Infliximab: Targets TNF-alpha in inflammatory diseases
Abciximab: Targets an integrin, preventing activated platelets from aggregating
184
185
What does IL5 do?
Recriuts and activates eosinophils
B cell proliferation
186
What does IL4 do
Recruits and activates mast cells
Recruits and activates basophils
Proliferation of TH2
IgE production
Inhibits TH1 development
187
What does G-CSF do
Recruits granulocytes (neutrophils, eosinophils, basophils)
188
What does erythropoeitin do
increases RBC production
189
What does Thrombopoein do
Increases production of platelets
190
What does IL10 do
Supresses the immune system
191
What does IL17 do
activates fibroblasts
activates endothelial cells
proinflammatory
recruits neutrophils
192
What does TGF-beta do
IgA production
TH17 differentiation
Promotes Treg
Inhibits immune system
