Immunology Flashcards Preview

Molecular Medicine > Immunology > Flashcards

Flashcards in Immunology Deck (192):
1

receptors of macrophage

TLR

Mannose R

CR R

Fc R

C3a and C5a R

2

receptors of neutrophil

TLR

CR R

Fc R

C3a and C5a R

3

receptors of basophil

IgE R

4

receptors of mast cell

IgE R

C3a and C5a R

5

receptors of NK cell

MICA stress R

MHC I R

Fc R

6

receptors of dendritic cell

TLR

Mannose R

7

cytokines produced by macrophages

TNF-alpha

IL6

IL1

CXCL8

IL12.

8

cytokines produced by neutrophil

TNF-alpha

9

cytokines produced by eosinophil

prostaglandins

unspecific cytokines

10

cytokines produced by basophil

histamine IL4

11

cytokines produced by mast cell

histamine

12

cytokines produced by NK cell

IFN-gamma

perforin

granzymes

13

cytokines produced by dendritic cell

Co-stimulatory proteins

TNF-alpha

IL6 IL1

IL12

IFN-alpha

14

Functions of macrophages

phagocytosis

inflammation

T-cell activation

tissue repair

15

functions of neutrophil

phagocytosis

inflammation

16

functions of eosinophil

parasitic defense

phagocytosis

allergies

inflammation

17

functions of basophil

inflammation

parasitic defense

allergies

18

functions of mast cell

inflammation

19

functions of NK cell

viral control

tumour apoptosis

20

Ways in which macrophage work

form phagolysosome

APC

21

Ways in which neutrophils work

  • form phagolysosme (oxygen independent and dependent)

 

  • form NET (neutrophil extracellular trap):
  • -- toxic granules
  • -- chromatin

22

Ways in which eosinophils work

kill large parasites (by highly toxic granules and ROS)

cause inflammation (prostaglandins and cytokines)

levels increase when TH2 secretes IL5

23

ways in which basophils work

promote TH2 development

24

ways in which mast cells work

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

A image thumb
74

Explain the lectin pathway

A image thumb
75

Explain the alternate pathway

A image thumb
76

How does a mature dendritic cell activate a T cell

A image thumb
77

How does a CD8 cell kill an infected cell

A image thumb
78

How does a T cell activate a macrophage

A image thumb
79

How does a T cell activate a B cell

Sends survival signals

A image thumb
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

A image thumb
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