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Flashcards in BRS Immunology Deck (228):
1

Function of immune system?

Removal of foreign material/microorganisms

2

Is innate immunity specific or non specific?

Nonspecific

3

Innate immunity is developed when?

By birth

4

The protective factors in innate immunity are independent of what?

Antigenic stimulus.

5

Is innate immunity fast or slow?

Fast

6

Is innate immunity first or second?

First

7

Is adaptive immunity specific or nonspecific?

Specific

8

How is adaptive immunity actively acquired? (2

Infection or vaccination

9

How is adaptive immunity passively acquired? 2

Placental transfer
Injection of specific antibody

10

4 main types of physical and chemical barriers to microbial invasion in innate immunity?

1. Skin and mucus membranes block and secrete
2. Defensins in phagocytic vacuoles are secreted and damage bacteria
3. Cathelicidins are released in granules to cause pores to form in bacteria
4. Lysozyme is released in lacrimal and saliva secretions

11

What cells are involved in early detection of pathogens? (3)

1. Macrophages
2. Neutrophils
3. Dendritic cells

12

Macrophages, neutrophils, and dendritic cells all possess what type of special receptor?

Pattern Recognition receptors

13

Pattern recognition receptors recognize what?
Which are found where?

Pathogen-Associated Molecular patterns (PAMP's)

Found on many microorganisms

14

One of the most important types of PRR's is what?

Toll-like receptors

15

Toll like receptors recognize what?

PAMP's on selective microorganisms

16

Upon binding a toll-like receptor to a PAMP, what does the cell do?

Releases Interleukin

17

Function of interleukin? 3

1. Incite inflammation
2. Incite phagocytosis
3. Removal of organism

18

Natural killer cells detect host cells with what main feature?

Depressed levels of major histocompatability class I molecules which is caused by viruses

19

NK cells binding to an infected cell's MHC class I is through what receptor?

Killer-activated receptor

20

How can a cell with adequate MHC class I levels prevent destruction by NK cells?

NK cells have a Killer Inhibition Receptor which determines if a cell has adequate MHC I levels

21

What initiates inflammation?

Microbial induced release of pro-inflammatory cytokines

22

Pro-inflammatory cytokines include? (2)

TNF-Alpha
IL-1

23

Pro-inflammatory cytokines induce what? 2

Adhesion molecules on leukocytes (Integrins)
Adhesion molecules on endothelial cells (selectins)

24

How do neutrophils slow their flow in order to undergo diapedesis into injury site?

By neutrophils' integrins binding to endothelial selectins and intracellular adhesion molecules (ICAM)

25

Phagocytic cells are recruited by what chemokines? 3

IL-8
Macrophage inflammatory protein (MIP)
Interferon-gamma (IFN-gamma)

26

First cells to arrive at seen of infection?

Neutrophils

27

What follows neutrophils to infection site? (3)

1. Macrophages
2. Monocytes
3. Lymphocytes

28

Phagocytized membrane-enclosed organisms are destroyed in phagocytic vacuoles by what? 4

1. Lysosomal enzymes
2. hydrogen peroxide
3. Nitric oxide
4. O2-anion

29

Repair of the damage caused by excessive inflammation is done by what two ways?

1. Down-regulate cytokines
2. Produce extracellular matrix

30

How are cytokines down-regulated in post-infection?

IL-4, IL-10, and TGF-Beta down regulate the cyotkines

31

How is extracellular matrix produced in post-infection?

PDGF and TGF-Beta induce it following increased proliferation and activation of fibroblasts

32

Chemokines are induced to release by what event?

Injury

33

How do chemokines function?

Transmit signals through seven transmembrane receptors that activate and recruit leukocytes to tissue damage sites

34

Two categories of chemokines based on sequence pair of amino acid cysteine?

1. C-X-C Chemokines (Alpha)
2. C-C Chemokines (Beta)

35

Alpha chemokines attract what mostly?

Neutrophils

36

Examples of alpha chemokines include what? 5

IL-8, platelet factor 4, IFN-gamma, inducible protein 10, macrophage activation factors

37

What do beta chemokines attract mainly?

Monocytes and T lymphocytes

38

Examples of beta chemokines include what?

MCP's
MIP
RANTES

39

What are cyotkines?

Intracellular signaling proteins acting locally by binding to high affinity receptors

40

Two main characteristics of chemokines as a whole?

1. Redundant: Many cytokines induce same response
2. Pleiotrophic: A single cytokine can induce many different responses

41

Steps of Neutrophils undergoing diapedesis? 6

1. Injury occurs and induces release of IL-1 and TNF-alpha
2. IL-1 and TNF-alpha cause selectins to be expressed
3. Endothelial selectins bind to PMN's selectin receptor to cause "rolling"
4. IL-8, MIP, and MCP release cause activation of PMN's integrins
5. Integrins bind to endothelial ICAM's
6. Diapedesis occurs and is facilitated by PECAM-1

42

What are lymphokines?

Cytokines made by lymphocytes

43

What are examples of endogenous pyrogens? (3)

IL-1
IL-6
TNF-alpha

44

What induces MCP, IL-8, and the acute phase resposne?

Endogenous pyrogens (IL-1, IL-6, TNF-alpha)

45

Functions of TGF-Beta 5

1. Wound healing
2. Immunosupressive
3. Inhibits IL-2
4. Inhibits proliferation of many cells
5. promotes switching of B cell synthesis to IgA

46

Humoral immunity is mediated by what?

Antibodies

47

Humoral immunity is responsible for what?

Neutralizing microorganisms and toxins and removes antigens in the body fluids by amplifying phagocytosis or lysis by complement

48

Cell-mediated immunity is mediated by what types of cells? (3)

Cytotoxic T
NK Cells
Activated macrophages

49

Cell-mediated immunity is responsible for what?

Eradicating microorganisms inside body cells

50

Two central lymphoid organs?

Bone marrow
Thymus

51

What happens at the central lymphoid organs?

Immunocompetent cells are developed

52

Peripheral lymphoid organs include what? (4)

1. spleen
2. lymph nodes
3. Tonsils
4. peyer's patches

53

What happens at peripheral lymphoid organs?

Immunocompetency is expressed

54

Multipotential stem cells oiginate where? (2)

1. fetal liver
2. bone marrow

55

When stem cells migrate to fetal thymus, they acquire what?

Phenotypic characteristics of T cells

56

T cells are characterized by what special protein markers?

Clusters of Differentiation (CD)

57

What are the major CD's on all peripheral T cells?

CD2 and CD3

58

CD4 defines what subset of T Cells?

Helper T cells

59

Helper T cells do what?

Aid responsiveness of B cells and other immunocompetent cells

60

Helper T cells differentiate into what 3 types?
Based on what?

Th0, Th1, Th2

Cytokines expressed

61

CD8 defines what subset of T cells?

Cytotoxic T cells

62

Regulatory T cells (Tregs) are composed of what two types?

1. Naturally occurring with (CD4, CD25, and FoxP3 markers)
2. Adapative

63

Naturally occurring Tregs can do what?

Supress other T cells

64

Adaptive Tregs are functional when?

End of immune response

65

Antigenic receptors are specific for what?

Each antigen epitope

66

What are the two types of antigenic receptors on T cell membranes?

Alpha:Beta TcR
Gamma:Delta TcR

67

The homing area exists where?

Periarteriolarly in spleen
Paracortical and deep cortical regions in lymph
GI
Bronchus

68

What percentage of T cells leave thymus?
What happens to rest?

1-2%

Apoptosis

69

What are the stages of development of Th1 cell? 8

1. CD34 Stem cell is the start
2. After getting thymic hormones, becomes cortical thymocyte
3. Acquire CD2, CD25, CD44
4. Acquire CD1, CD2, CD4, CD8 and lose CD44 and CD25
5. Acquire TCR-CD3 complex and lose CD1 in medulla
6. Leave thymus and 90% obtain alpha:Beta TCR
7. 70% become ThO with CD4+ and CD8-
8. Become Th1 and secrete IL-2, IFN-gamma, and TNF-alpha

70

What are the stages of development of Th2 cell? 8

1. CD34 Stem cell is the start
2. After getting thymic hormones, becomes cortical thymocyte
3. Acquire CD2, CD25, CD44
4. Acquire CD1, CD2, CD4, CD8 and lose CD44 and CD25
5. Acquire TCR-CD3 complex and lose CD1 in medulla
6. Leave thymus and 90% obtain alpha:Beta TCR
7. 70% become ThO with CD4+ and CD8-
8. Become Th2 and secrete IL-4, IL-5, IL-6, IL-10, IL-13

71

What are the stages of development of cytotoxic and supressor T cells? 8

1. CD34 Stem cell is the start
2. After getting thymic hormones, becomes cortical thymocyte
3. Acquire CD2, CD25, CD44
4. Acquire CD1, CD2, CD4, CD8 and lose CD44 and CD25
5. Acquire TCR-CD3 complex and lose CD1 in medulla
6. Leave thymus and 90% obtain alpha:Beta TCR
7. 25% become CD8+ and CD4-
8. Differentiate into either cytotoxic or suppressor T cell

72

What are stages of development of gamma:delta TCR T cells?

1. CD34 Stem cell is the start
2. After getting thymic hormones, becomes cortical thymocyte
3. Acquire CD2, CD25, CD44
4. Acquire CD1, CD2, CD4, CD8 and lose CD44 and CD25
5. Acquire TCR-CD3 complex and lose CD1 in medulla
6. Leave thymus and 4% obtain gamma:delta TCR with CD3+, CD8-, and CD4-

73

What do T cells with alpha:beta TcR's respond to?

Peptide antigens bound to MHC

74

What do T cells with gamma:delta TcR's respond to?

Nonpeptide antigens but lack MHC restrictions

75

Function of T cells with gamma-delta receptors? 2

1. antibacterial
2. Increased Cell mediated immunity against viruses

76

Th1 cells are involved in what? 3

1. Activation of B cells, Tc cells, Th cells, and APC's
2. Downregulation of Th2 cell functions
3. Increased CMI

77

Th2 cells are involved in what? (5)

1. B cell differentiation
2. Activation of eosinophils
3. Downregulation of Th1 cell functions
4. Class switching
5. increased antibody

78

If stem cells remain in bone marrow, they acquire what?

Phenotypic CD markers of B cells

79

What distinguishes the B-cell antigenic receptor from the T cell?

Membrane bound, epitope-specific, monomeric IgM antibody

80

Upon antigenic and cytokine stimulus, what will B cells do?

Synthesize and secrete its antibody

81

B cell homing areas exist primarily where? (4)

Splenic follicles
Red pulp
Lymph nodes
MALT

82

T and B cells gain immunocompetency when?

Antigenic stimulus

83

What is the clonal selection theory

The total population of T and B cells is made up of millions of individual clones of cells, each dfined by specific receptor for a particular antigen epitope.

84

Antigen is modified by by what?

APC's

85

Antigen selects what cells upon presentation?

Those T or B cells with membrane-bound receptor specific for its epitope

86

What are the stages of B cell development?

1. Stem cells
2. Gains CD19, CD22, and mu chain D-J gene arrangements to become pro-B Cell
3. Addition of CD9, CD10, and V-DJ-C gene arrangements with mu chains appearing to become Pre-B cell
4. Add CD20, CD21, CD37 and lose CD9 and CD10 while IgM and IgD receptors appear to become immature B cell
5. Become mature B cell
6. Activation by antigen and T cell cytokines IL-2, IL-4, IL-5, and IL-6 cause B cell to activate
7. Activated B cell becomes either plasma cells or memory cells

87

Plasma cells secrete what antibody?

IgM

88

Plasma cells have an Ig switch to what?

IgG, IgA, IgE

89

What is an epitope?

Short sequence of amino acids or sugars in an antigen molecule that binds to the hypervariable region on an antibody

90

What is the number of repeats of an epitope called?

Valence

91

Does a microorganism have more than one epitope?

yes

92

What is a hapten?

Portion of antigen molecule that contains epitope

93

A superantigen can do what?

Link multiple T cells to MHC of APC via T-cell regions independent of their specific peptide binding sites resulting in activation of many nonspecific T cells and APC, causing secretion of extraordinary amounts of cytokines

94

What can thymus independent antigens do?

Activate B cells polyclonally without regard to B-cell specificity and without Th cell involvement

95

Thymus independent antigens are found where?

LPS on Gram negative bacteria

96

What is an antibody?

Mucoproteins found in gamma-globulin fraction of serum on electrophoresis

97

General structure of antibodies?

Four chain protein with two heavy and two light chain polypeptides linked by disulphide bonds

98

What determines which of the five classes an antibody is?

Amino acid sequence on H chain

99

H and L chains are each divided into what regions?

1. constant region
2. variable region

100

The amino acid sequence of variable regions on heavy and light chains varies with what?

The epitope toward which the particular antibody is directed.

101

What area of the variable region is extremely specific for each H and L chain?

Hypervariable region

102

The hypervariable region of each H and L chain associate to form what?

Two epitope binding regions known as the antibody idiotype

103

What is a monoclonal antibody?

Antibody of a single specificity

104

How do you make a monoclonal antibody?

Fuse splenic B cells from immunized animal with malignant plasma cells to form hybridoma that secretes the desired antibody

105

IgG is composed of what chains?

Two L and Two H chains

106

Four subclasses of IgG?

Lambda 1, lambda 2, lambda 3, lambda 4

107

What does papain cleave igG into?

1. Two Fab fragments
2. One Fc fragment

108

What can Fab do?

Contains one reactive site so can bind antigen but cannot agglutinate antigen

109

What can Fc do? (4)

1. Activate complement
2. Control catabolism of IgG
3. Fix IgG to tissues or cells via Fc receptor
4. mediates placental transfer of antibody

110

What can pepsin do to IgG?

Splits IgG behind the disulfide bond leaving the two Fab's together to form F(ab')2 and Fc

111

What can F(ab')2 do?

Is bivalent so can bind antigen and form lattice to remove antigens

112

What happens to Fc after pepsin action?

Degraded

113

Which is removed faster from circulation, F(ab')2 or intact IgG?

F(ab')2

114

How common is IgG of all antibodies?

Most common

115

What does IgG look for when binding to a cell?

Cell that possesses a receptor for the Fc fragment from IgG

116

What are the two structural forms of IgM?

Monomer
Pentamer

117

IgM monomer is made by what cells?

B cells

118

IgM is kept where?
And has what function?

B cell membrane
Serves as B-cell receptor specific for a single antigenic epitope

119

How does the hypervariable region of IgM monomer differ between cells?

It differs for each B-cell clone

120

Secreted igM exists as what?

Pentamer form

121

What is structure of IgM pentamer?

Five monomeric IgM molecules joined together by J chain

122

What causes IgM pentamer to be secreted?

Antigen and cytokine activation of B cells

123

How similar are IgM pentamer and IgM monomer hypervariable regions of the same cell?

The same

124

Of the 10 binding sites on IgM pentamer, how may are high affinity?

5

125

When is IgM release in relation to other immunoglobulins?

First

126

What does IgM do?

Fixes complement

127

What are three forms of IgA?

1. Monomer
2. Dimer
3. Dimer plus secretory piece

128

IgA dimer is transported across what barriers?
Via what?
Which is a receptor for what?

Respiratory and intestinal mucosal barriers

Secretory piece

IgA Fc region on the mucosal epithelium

129

The secretory piece also has what function besides transport of IgA dimer?

Protect IgA from ptoeolysis

130

Two subclasses of IgA?

Alpha1 and alpha2

131

IgA is found in high concentrations in what?

Secretions

132

IgA is found in what locations or secretions? (4)

Mucosal tissues
Saliva
Tears
Colostrum

133

What does IgA do?

Blocks bacteria, viruses, and toxins from binding to host cells

134

IgE has how many constant domains?

4

135

What mediates the B-cell switch to igE production?

IL-4

136

Why are IgE levels so low?

Its Fc region binds avidly to mast cells and basophils

137

How does IgE bind to mast cells and basophils?

Via Fc epsilon receptors on these cells

138

Binding of antigen to cells with IgE triggers release of what?

Vasoactive amines such as histamine that cause atopic disease such as hives and anaphylaxis

139

Does IgE cross placenta?

No

140

Does IgE fix complement conventionally?

No

141

Binding of IgE to IL5 activated eosinophils results in what?

Elimination of parasitic Helminths

142

IgD is found where?

B-cell membranes of 15% of ewborns and on adult blood lymphocytes in conjunction with IgM

143

IgD acts as what on B cells?

Receptor for antigen

144

3 main reasons for diversity of antibodies in humans?

1. Genetic diversity
2. Random Selection
3. Allelic exclusion

145

Do the same genes or different genes code for the variable and constant regions of H and L chains?

Different

146

Explain the rearrangement of genes in antibody synthesis?

The variable region and constant region genes are rearranged during differentiation such that any one of the different variable region genes can be linked to a single constant region gene.

147

For formation of the L chain, what additional gene sequence is needed?
What does it link?

Joining segment

Links VL gene to the CL region gene

148

For formation of the H chain, how are all the genes linked?

A diversity segment links the VH gene to the J gene. These genes are then fused with the CH gene

149

What determines H chain class switching?

Rearrangement of class genes in the CH region determines the switch from mu and delta to gamma3, gamma1, alpha1, gamma2, gamma4, epsilon, and alpha2.

150

What mediates H chain class switching?

T-cell cytokines (IL-4, IL-13, IFN-gamma, TGF-Beta

151

Explain the steps of Kappa light chain synthesis?

1. Germ line DNA has one V region joined to a J region resulting in B-cell DNA (Rearrangement)
2. B-cell DNA is transcribed into primary RNA.
3. Splicing forms a mature mRNA
4. Translated into Kappa L-chain polypeptide

152

How does Lambda light chain synthesis differ from kappa?

Instead of just one constant gene for Kappa, there are six possible constant exons that can be used.

153

Random selection by each B cell from the variety of V, D, and J germ line genes results in what?

A huge variety of possible structures for VL and VH epitope binding regions.

154

Why does allelic exclusion occur in antibody synthesis?

Only one of the two parental alleles is expressed by a single B cell

155

What do HLA's control?

1. Discrimination between self and nonself
2. Antigen presentation to T cells

156

One restriction on HLA's control?

Only can control discrimination and presentation to the same HLA type since self-MHC restriction occurs

157

HLA's determine what?

Individual's susceptibility to immunologic disorders and infections agents.

158

HLA's are organized into what three classes of MHC?

MHC-I
MHC-II
MHC-III

159

Class I HLA/MHC are what type of molecule?
Found where?

Glycoproteins

Membranes of most nucleated cells

160

Class I HLA's are linked to what cell?
Through what molecules? (2)

Cytotoxic T Cell

1. CD8
2. Present epitopes to specific Tc receptors

161

What is structure of Class I MHC?

Alpha chain with 3 domains
Beta-2 microglobulin (invariant protein)

162

The peptide binding site is where on class I MHC's?

Between domains alpha1 and alph2

163

MHC I's bind peptides of what length?

8 to 10 AA's

164

Class II HLA's are what type of mlecules?
Found where?

Glycoproteins
Membranes of dendritic cells, macrophages, activated T cells, and B cells

165

What are the three regions that encode Class II HLA's?

DP, DQ, and DR

166

Class II HLA's are linked to what type of cell?

Through what molecules? (2)

Helper T cells

1. CD4
2. Present epitopes to specific Helper T cell receptors

167

What is the structure of Th cell?

Two chains alpha and beta with two domains each

168

The peptide binding site of MHC II's is formed by what?

Juxtaposition of alpha1 and beta1 domains

169

What size of peptide do MHC II's bind?

13-18 AA's

170

Class III HLA's control what?

Certain cerum proteins

171

Describe the polymorphism of HLA's

Many alleles of class I and II are present at each locus on chromosome 6 allowing haplotypes from both parents to be inherited and expressed codominantly.

172

The TCR is a dimer of what? 2

Either alpha and beta chains (95%)
Or gamma and delta chains (5%)

173

What do TCR's recognize

Antigenic epitopes as peptidic fragments bound to either class I or clas II HLA molecules on an APC

174

What determines whether humoral or cell-mediated immunity will occur?

The coreceptors on the T Cell (CD4 or CD8)

175

What two things must bind together for humoral immunity?

CD4 to Class II

176

What two things must bind together for cell mediated immunity?

CD8 to Class I

177

Union of specific TCR and coreceptor with the peptide HLA membrane complex is associated with what?

Signal transduction of CD3 complex into cytoplasm

178

Genetic diversity in TCR's are accomplished through what?

TCR's

179

How are TCR's synthesized? 3

1. Germ line DNA undergoes rearrangement by recombinase enzymes RAG-1 and RAG-2
2. Randomly selected V gene is joined to a J gene and is transcribed
3. Transcript combined with Constant region gene and translated

180

What controls the genetic expression of TCR's?

Allelic exclusion

181

What is affinity the measure of?

Binding energy between an antibody and univalent epitope

182

What is avidity?

Total binding energy between an antibody and a multivalent antigen

183

What is the complement complex a part of?

Both innate and adaptive immunity

184

The complement complex is comprised of what?

Nine major factors (C1 to C9) most of which are pro-enzymes present at constant levels in serum.

185

What does the classical complement pathway result in?

Lysis of microbial or mammalian cells to which IgM or a doublet of IgG1, IgG2, or IgG3 antibody has been bound to the membrane followed by sequential fixation of C to the antigen-antibody complex.

186

What are the steps of the classical complement pathway? 8

1. C1qrs is bound initially via C1q
2. Cleavage of C4 and C2
3. C4b and C2a bind to the cell surface as C4b2a
4. C4b2a act as C3 convertase that cleaves C3 into C3a and C3b
5. C3b complexes with C4b2a to become a C5 convertase that cleaves C5 into C5a and C5b
6. C5b combines with C6 and C7 and insert into cell membrane
7. C8 and C9 combine with C5b,6,7 complex to form the membrane attack complex ( MAC)
8. The MAC causes increased permeability leading to cell lysis

187

The alternate pathway is activated by what? 4

1. Cell walls of certain Gram-negative and Gram-positive bacteria
2. Viruses
3. Yeasts
4. Aggregated IgA

188

The alternate pathway acts independent of what? (4)

1. Antibody
2. C1
3. C2
3. C4

189

Steps of alternate pathway of complement? 5

1. Initiation by cell wall absorption of small amounts of C3b in normal serum
2. Binding of Factor B to C3b
3. Factor D catalyzes Factor B into Ba and Bb
4. The resulting complex C3bBb has C3 convertase activity to generate additional C3b
5. C3bBbC3b forms and acts as C5 convertase leading to further reactions resulting in MAC.

190

The mannose-binding lectin pathway follows what?

Binding of an acute phase protein, MBL, onto mannose residues on cell walls of certain bacteria, fungi and viruses

191

The MBL complex acts similar to what?

C1 and so follows classical pathway forming C3 and C5 convertases that result in cell lysis via MAC.

192

C3a and C5a also have what functions?

1. Vasodilators
2. Chemotaxis allowing cells and cytokines to join response

193

Binding of fragment C3b to microorganisms promotes what?

Opsonization through C3b receptor on phagocytic cells

194

If antigen entry is intravenous, where is it taken up?

Spleen

195

If antigen entry is non-intravenous what happens

Antigen is trafficked to the lymph node draining the site of entry and then processed by APC's

196

What are the steps of exogenous protein antigen processing?

1. Pinocytosis from extracellular environment
2. Processed in acidic endosomal vesicles
3. Vesicles then bind to the cleft in MHC class II molecules
4. Molecules are transported to cell membrane where they can be presented to CD4 T Cells
5. CD4 T cells activate B cells for antibody synthesis

197

Viruses and intracellular parasitic antigens are processed in what steps? 4

1. Synthesized endogenously within APC cytoplasm and ER
2. Processed to peptides by proteasomes
3. Peptides bind to the cleft in MHC class I molecules
4. MHC's migrate to the APC membrane where they are presented to CD8 T cells to initiate CMI

198

CMI is directed against who?

Intracellular-dwelling microorganisms and aberrant, endogenous cells such as cancer cells

199

What is antibody-dependent cellular cytotoxic reaction?

Feector cell is linked to the target cell by an antibody bridge with the Fab portion binding to the specific membrane antigen on the target cell and the Fc portion binding to the Fc receptor on an activated effector cell

200

Activation of T cells is initiated when?

Specific CD4 or CD8 T cell receptor binds to the appropriate APC peptide-HLA complex

201

What molecules strenghten the binding of TcR to APC:HLA complex? 3

1. CD28
2. CD2
3. LFA-1

202

What is function of CD28?

Binds to B7.1 on APC and increases IL-2 synthesis

203

What is function of CD2?

Binds to leukocyte functional antigen (LFA-3)

204

What is function of CTLA4?

Binds to B7.2 which down regulates IL-2 synthesis following activation

205

An activation signal to the T cell is transduced through what?

CD3 complex of 3 polypeptides: gamma, delta, epsilon, and two zeta

206

Th1 cell induces what?
Following what?

CMI

Binding of Th1 to the peptide-class I MHC

207

What do Th1 cells secrete? 5

1. IL-2
2. IFN-gamma
3. TNF-alpha
4. IL-12
5. IL-18

208

Function of IL-2

Necessary for T and B cell transformation

209

Function of IGN-gamma?

1. Enhances CMI by activating macrophages and NK cells
2. Triggers HLA antigen presentation by endothelial cells
3. Suppress antibody formation by down-regulating IL-4 synthesis

210

Function of TNF-alpha

Activates macrophages, and syergizes with IL-1 in inducing and stimulating the acute phase response

211

IL-12 and IL-18 function?

Aid the transition of macrophages, Tc cells, and NK cells to CMI

212

The Th2 cell induces what?
Following what? (2)

Activation of B Cells and humoral immunity

1. Binding to peptide-class II MHC
2. Stimulation by IL-2

213

Th2 secretes what upon activation?

1. IL-4
2. IL-5
3. IL-10
4. IL-13

214

IL-4 does what? 4

1. Develops antibody synthesis by stimulating B-cell differentiation
2. Helps in IgE production
3. Down regulates IFN-gamma by Th1
4. Suppress CMI

215

IL-5 does what? 3

1. Works with IL-4 and IL-2 to aid B-cell differentiation
2. Stimulates growth of eosinophils
3. Facilitates IgA synthesis

216

IL-10 does what?

Inhibits Th-1 release of IFN gamma and IL-2 thus reducing activation by IFN-gamma

217

IL-13 does what?

Mimics IL-4 actions, inhibiting Th1 cytokine release

218

B-cell response is initiated by what?

Antigen selecting the clone of B cells with the membrane-bound IgM antigen receptor that is specific for the antigen epitope

219

What triggers differentiation of B-cell clone into a large blast cell? 2

1. Binding of antigen
2. Stimuli from IL-2 and IL-4 from T cells

220

What stimulates continuation of B cell differentiation?

IL-5

221

H and L chains of B cell antibodies are synthesized under stimulation of what?

IL-5

222

What causes the B cell to differentiate into a plasma cell and secrete IgM?

IL-6

223

Gene arrangements on B cells result in what?

Switch to IgG, IgA, and IgE synthesis

224

What stimulates a plasma cell's switch to IgG production? (2)

IL-4 and IFN-gamma

225

What influences the plasma cell's switch to IgA production?

TGF-Beta

226

What stimulates a plasma cell's switch to IgE?

IL-4

227

What binding is required for a B cell to switch its antibody production?

CD40 on B cell to ligand on Th cell

228

A secondary response to the same antigen can result in what? 4

1. Shorter induction period to antibody synthesis
2. More class switching from IgM to IgG
3. Increased IgG with antibodies of higher affinity
4. Predominant IgA synthesis in mucosal tissues