IMMUNOLOGY- Lymphocytes Flashcards

1
Q

Which are the types of immunity?

A

Innate and Adaptative

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2
Q

These cells composed the Innate immunity

A

Neutrophils, machophages, monocytes, dendritic cells, NK cells (lymphoid origin), complement

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3
Q

Which are the cells that manage adaptative immunity?

A

T cells, B cells and circulating antibodies

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4
Q

Which is the mechanism of resistance to innate immunity?

A

Germline encoded

Resistance persists through generations, does not change within an organisms lifetime

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5
Q

This is the mechanism of Resistance to adaptative immunity

A

Variation through V (D) J recombination during lymphocyte development

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6
Q

In this immunity the microbial resistance is not heritable

A

Adaptative immunity

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7
Q

The immune response to pathogen is nonspecific

A

Innate immunity

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8
Q

How much time does it takes for Innate immunity to respond to pathogens?

A

Occurs rapidly (Minutes to hours)

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9
Q

How is the response to pathogens in adaptative immunity?

A

Highly specific, refined over time

Develops over long periods; memory response is faster and more robust

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10
Q

These are physical barriers for innate immunity

A

Epithelial tight juctions, mucus

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11
Q

For innate immunity these are the secreted proteins

A

Lysozyme, complement, CRP, defensins

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12
Q

Which are the secreted proteins for adaptative immunity?

A

Immunoglobulins

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13
Q

Pattern recognition receptors that recognize pathogen- Associated molecular patterns (PAMPs)

A

Toll like receptors (TLRs)

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14
Q

These are the key features in pathogen recognition for innate immunity

A

Toll like receptors (TLRs)

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15
Q

Which are consider pathogen associated molecular patterns (PAMPs)?

A

LPS (gram negative bacterias)
Flagellin (bacteria)
ssRNA (viruses)

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16
Q

For this immunity we find the pathogen associated molecular patterns (PAMPs)

A

Innate immunity

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17
Q

Which cells manage the pathogen recognition for adaptative immunity?

A

Memory cells

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18
Q

In adaptative immunity what are the memory cells?

A

Activated B and T cells

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19
Q

How do Memory cells work?

A

Subsequent exposure to a previously encountered antigen→ Stronger immune response

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20
Q

How encodes MHC?

A

HLA genes

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21
Q

What is the function of MHC?

A

Present antigen fragments to T cells and bind TCRs

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22
Q

How many types of MHC exist?

A

MHC I

MHC II

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23
Q

Which are the loci for MHC I?

A

HLA-A, HLA- B, HLA-C

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24
Q

These are the loci for MHC II

A

HLA-DR
HLA- DP
HLA- DQ

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25
Q

These are the sites where MHC I bind

A

TCR and CD8

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26
Q

For MHC II these are the binding sites

A

TCR and CD4

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27
Q

Whcih cells express MHC I?

A

On all nuclated cells

Not expressed onRBCs

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28
Q

Who can express MHC II?

A

Only on APCs

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29
Q

Which is the function of MHC I?

A

Present endogenousky synthesized antigens (eg viral) to CD8+ cytotoxic T cells

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30
Q

How does MHC II works?

A

Present exogenously synthesized proteins (eg bactrerial proteins, viral capsid proteins) to T- helper cells

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31
Q

How are the antigen loaded for MHC I?

A

Antigen peptides loaded onto MHC I in RER after delivery via TAP peptide transporter

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32
Q

This is the way antigen load in MHC II

A

Antigen loaded following release ofinvariant chain in an acidified endosome

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33
Q

Who manages the mode of transport to cell surface in MHC I?

A

β2 microglobulin

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34
Q

Which HLA subtype is associated with Hemochromatosis?

A

A3

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35
Q

These diseases are associated to B27 HLA subtype

A

Psoriatic arhrhritis
Ankylosing spondylitis
Arthritis of inflammatory bowel disease
Reactive arthritis (formerly Reiter syndrome)

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36
Q

Which are consider seronegative arthropathies?

A
The ones associated to B27 subtype
Psoriatic arhrhritis
Ankylosing spondylitis
Arthritis of inflammatory bowel disease
Reactive arthritis (formerly Reiter syndrome)
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37
Q

These HLA subtypes are related to Celiac disease

A

DQ2/ DQ8

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38
Q

Which diseases are related to DR2 HLA subtype?

A

Multiple sclerosis, hay fever, SLE, Goodpasture syndrome

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39
Q

These diseases are related to DR3

A

Diabetes mellitus type 1, SLE, Graves disease

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40
Q

For DR4 HLA subtype these are the related diseases

A

Rheumatoid arthritis, Diabetes mellitus type 1

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41
Q

These health problems are related to DR5 subtype

A

Pernicious anemia → vitamin B12 deficiency, Hashimoto thyroiditis

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42
Q

Which cells are affected by Natural Killers?

A

Virally inffected cells and tumor cells

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43
Q

What is the effect of Natural Killers to Virally inffected cells and tumor cells?

A

Use perforin and granzymes to induce apoptosis

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44
Q

Who enhance the activity of Natural killers?

A

By IL-2, IL-12, IFN-β and IFN α

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45
Q

What induces the activity of Natural killers?

A

Induced to kill when exposed to a nonspecific activation signal on target cell and/ or to an absence of class I MHC on target cell surface

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46
Q

This is another mechanism of how Natural killers kills

A

Via antibody dependent cell mediated cytotocixity

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47
Q

How does Via antibody dependent cell mediated cytotocixity makes natural killer work?

A

CD 16 binds Fc region of bound Ig, activating the NK cell

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48
Q

Which are the three functions of B cells?

A

Recognize antigen
Produce antibody
Maintain immunologic memory

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49
Q

How do B cells recognize antigen?

A

Undergo somatic hypermutation to optomize antigen specificity

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50
Q

This is the way B cells produce antibodies

A

Differentiate into plasma cells to secrete specific immunoglobulins

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51
Q

How do B cells immunologic memory work?

A

Memory B cells persist and accelerate future response to antigen

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52
Q

These cells manage acute and chronic cellular organ rejection

A

T cells

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53
Q

Which is the function of CD4+ T cells?

A

Help B cells make antibody and produce cytokines to activate other cells of immune system

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54
Q

This is the function of CD8+ T cells

A

Kill virus-infected cells directly

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55
Q

Who manages delayed cell mediated hypersensitivity?

A

T cells

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56
Q

Which is the immunologic type related to cell mediated hypersensitivity?

A

IV

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57
Q

This MHC is related to CD4+ T cells

A

MHC II

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58
Q

Which T cells are related to MHC I?

A

CD8+ T cells

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59
Q

Where is produced T cell precursor?

A

Bone marrow

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60
Q

Which organ manages positive and negative selection of T cells?

A

Thymus

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61
Q

Which cells pass through positive selection?

A

Indiferentiated T cell CD4+ and CD8+

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62
Q

Where is carried the Positive selection of T cells?

A

Cortex of Thymus

63
Q

Which cells can survive positive selection?

A

T cells expressing TCRs capable of binding surface sekf MHC molecules survive

64
Q

This is the site for Negative selection of T cells

A

Medulla

65
Q

What is the negative selection of T cells?

A

T cells expressing TCRs with high affinity for self antigens undergo apoptosis

66
Q

Which is the differentiation procees of T cells

A

1º T cell precursor (Bone Marrow)
2º Positive selection (Cortex Thymus)
3º Negative selection (Medulla Thymus)
4º Action in lymph nodes

67
Q

This is the effect of CD8+ T cells

A

Kills virus infected cells
Neoplastic cells
Donor graft cells

68
Q

Which are the main differentiated T cell types of Helper T cell?

A

Th1 cell
Th2 cell
Th17 cell
T reg

69
Q

Who stimulates Th1 cell conversion?

A

IL-12

70
Q

This interleucin stimulates the conversion of CD4 T cell to Th2 cell

A

IL-4

71
Q

Who stimulates Th17 cell conversion from T helpers?

A

TGF β + IL-6

72
Q

Who stimulates T reg cell conversion from T helpers?

A

IL-6

73
Q

This is another name for CD4 T cell

A

Helper T cell

74
Q

Who are consider Antigen presenting cells (APC)?

A

B cells
Macrophages
Dendritic cells

75
Q

Which are the two signals require to activate T cells?

A

B cell activation

Class swithching

76
Q

Which is the procces of NAive T cell activation?

A
  1. Foreign body is phagocytosed by dendritic cell
  2. Foreign antigen is presented on MHC II and recognized by TCR in Th (helper) cell. Antigen is presente on MHC 1 to Tc (cytotoxic) cells (signal 1)
  3. Costimulatory signal is given by interaction of B7 and CD28 (signal 2)
  4. Th cell activates and produces cytokines. Tc cell activates and is able to recognize and kill virus- infected cells
77
Q

Which is the mechanism of B cell activation and class swithching?

A
  1. Helper T cell activation
  2. B cell receptor- mediated endocytes; foreign antigen is presented in MHC II and recognized by TCR in Th cell (signal 1)
  3. CD 40 receptor on B cell binds CD40 ligand in Th cell (signal 2)
  4. Th cell secretes cytokines that determine Ig vlass switching of B cell. B cell activates and undergoes switching, affinity maturation and antibody production
78
Q

Which are the two main groups of Helper T cells?

A

Th1

Th2

79
Q

What does Th1 secretes?

A

IFN γ

80
Q

Which cells can be activated by Th1?

A

Macrophages and cytotoxic T lymphocytes (CTLs)

81
Q

Who inhibits Th1 cell?

A

IL-4 and IL-10

82
Q

Who produces IL-4 and IL-10 that inhibits Th1 cell?

A

Th-2

83
Q

Which interleucins are secreted by Th-2?

A

IL-4, IL-5, IL-6, IL-13

84
Q

Which is the funtion of TH2 cell?

A

Recruits eosinophils for parasite defense and promotes IgE production by B cells

85
Q

Who can inhibit Th-2?

A

Inhibited by IFN-γ (from Th1 cell)

86
Q

How does Macrophage- lymphocyte interaction works?

A

Macrophage release IL-12, which stimulates T cells to differentiate into Th1 cells. Th1 cells relase IFN γ to stimulate macrophages

87
Q

Who binds MHC II on APC?

A

Helper T cell have CD4

88
Q

How does Cytotoxic T cells kill virus infected, neoplastic and donor graft cells?

A

Indcuing Apoptosis

89
Q

This is the mechanism of action of Cytotoxic T cells

A

Release cytotoxic granules containing preformed proteins

90
Q

Which are preformed proteins produced by Cytotoxic T cells?

A

Perforin
Granzyme B
Granulysin

91
Q

Which is the function of perforins?

A

Helps deliver the content of granules into target cell

92
Q

What is the Granzyme B?

A

A serine protease, activates apoptosis inside target cell

93
Q

This is how Granulysin work

A

Antomicrobial, induces apoptosis

94
Q

Binds to MHC I on virus infected cells

A

Cytotoxic T cells have CD8

95
Q

Which is the function Regulatory T cells?

A

Help maintain specific immune tolerance by suppressing CD4 and CD8 T cell effector function

96
Q

Who identifies Regulatory cells?

A

Expression of cell surface markers CD3, CD4, CD25 (α chain of IL-2 receptor) and transcription factor FOXP3

97
Q

What do Activated regulatory T cells produce?

A

Anti-inflamatory cytokines like IL-10 and TGF β

98
Q

In Antibody structure who recognizes antigens?

A

Variable part of L and H chains

99
Q

Who fixes complement?

A

Fc portion of IgM abd IgG

100
Q

Who contributes fo Fc and Fab fractions?

A

Heavy chain contributes

101
Q

Who contributes only to Fab fraction?

A

Light chain

102
Q

What is the purpose of Fab fragment?

A

Antigen-binding fragment

103
Q

What does Fab fragment identifies?

A

Determines idiotype: unique antigen binding pocket

104
Q

How many antigens can a B cell expressed?

A

Only 1 antigen expressed per B cell

105
Q

Which are the characteristics of Fc fraction?

A

Constant
Carboxyl terminal
Complement binding
Carbohydrate side chains

106
Q

What does Fc fraction determines?

A

Determines Isotype (IgM, IgD, etc)

107
Q

Who generates antibody diversity?

A

Random “recombination” of VJ or V (D)J genes
Random combination of heavy chains with light chains
Somatic hypermutation
Adittion of nucleotides to DNA during recombination by terminal deoxynucleotidyl transferase

108
Q

Which are the light chains?

A

V (D)J genes

109
Q

This is the light chain

A

VJ genes

110
Q

When does the Somatice hypermutation happens?

A

Following antigen stimulation

111
Q

What happens during the opsonization?

A

Antibody promotes phagocytosis

112
Q

What happens in the neutralization by antibodies?

A

Antibody prevents bacterial adherence

113
Q

What is the relationship of Antibodies and Complement?

A

Antibodies activate complement, enhancing opsonization and lysis

114
Q

Which are the immunoglobulin isotypes?

A
IgG
IgA
IgM
IgD
IgE
115
Q

Which are the immunoglobulin isotypes expressed by mature lymphocytes on their surfaces?

A

IgM and IgD

116
Q

Where do B lymphocytes diffetentiate?

A

Germinal centers of lymph nodes by isotype switching

117
Q

What is isotype switching?

A

Gene rearrangement; mediated by cytokines and CD40 ligand

118
Q

What is the product of Isotype switching of B lymphocytes?

A

Plasma cells that secrete IgA, IgE or IgG

119
Q

Main antibody in secondary (delayed) response to an antigen

A

IgM

120
Q

Which is the most abundant immunoglobulin isotype in serum?

A

IgM

121
Q

Which are the main functions of IgM?

A

Fixes complement, crosses the placenta, opsonizes bacteria, neutralizes bacterial toxins and viruses

122
Q

This immunoglobulin isotype crosses placenta providing infants with passive immunity

A

IgM

123
Q

Prevents attachment of bacteria and viruses to mucous membranes

A

IgA

124
Q

Does IgA fixes complement?

A

No

125
Q

Which are the forms of IgA?

A

Monomer

Dimer

126
Q

When is presented IgA monomer and when dimer?

A

IgA monomer in circulation

IgA dimer when secreted

127
Q

How does IgA crosses epithelial cells?

A

By transcytosis

128
Q

Which is the most produced antibody overall?

A

IgA

129
Q

Where can we find IgA?

A

In secretions (tears, salivan mucus) and early breast milk

130
Q

What name does early breast milk receives?

A

Colostrum

131
Q

What does IgA does before secretion?

A

Picks up secretory component from epithelial cells

132
Q

Immunoglobulin isotype produced in the primary (immediate) response to an antigen

A

IgM

133
Q

Which are the alternative names to antigen for response?

A

Primary (immediate)

Secondary (delayed)

134
Q

Which is the function of IgM?

A

Fixes complement but does not cross the placenta

135
Q

Where is located IgM?

A

Antigen receptor on to the surface of B cells

136
Q

Which are the forms of IgM? When can we find each form?

A

Monomer on B cell

Pentamer when secreted

137
Q

Which is benefeat of pentamer shape of IgM?

A

Allows it to efficiently trap free antigens out of tissue while humoral response evolves

138
Q

Which Immunoglobulin isotypes does not cross the placenta?

A

IgM and IgA

139
Q

This Immunoglobulin isotype crosses placenta

A

IgG

140
Q

Which is the function of IgD?

A

Unclear function

141
Q

Where is IgD found?

A

Surface of many B cells and in serum

142
Q

This Immunoglobulin isotype has the lowest concentration in serum

A

IgE

143
Q

Which are the functions of IgE?

A

Binds mast cells and basophils
Cross links when exposed to allergen, mediating immediate hypersensitivity through release of inflammatory mediator such as histamine
Mediates immunity to worms

144
Q

How does IgE mediates immunity to worms?

A

By activating eosinophils

145
Q

Which reaction does IgE mediates?

A

Immediate hypersensitivity (Type I)

146
Q

How are classified Antigens types?

A

Thymus independent antigens

Thymus dependent antigens

147
Q

Which antigens are classified as Thymus independent antigens?

A

Antigens lacking a peptide component

148
Q

Give an example of Antigens lacking a peptide component

A

Lipopolysaccharides from gram negative bacteria

149
Q

Which is the characteristic of Thymus independent antigens?

A

Cannot be presented by MHC to T cells

150
Q

How immunogenic are Thymus independent antigens consider?

A

Weakly or nonimmunogenic

151
Q

What do Vaccines require in Thymus independent antigens?

A

Require boosters (eg pneumococcal polysacharide vaccines)

152
Q

What are the Thymus dependent antigens?

A

Antigens containing a protein component

153
Q

Which vaccine is an example of antigen containig a protein component?

A

Diphteria vaccine

154
Q

When does the class switching and immunologic memory occurs in Thymus dependent antigens?

A

Occurs as a result of direct contact of B cells with Th cells (CD40-CD40 ligand interaction)