IMMUNOLOGY- Lymphocytes Flashcards
1
Q
Which are the types of immunity?
A
Innate and Adaptative
2
Q
These cells composed the Innate immunity
A
Neutrophils, machophages, monocytes, dendritic cells, NK cells (lymphoid origin), complement
3
Q
Which are the cells that manage adaptative immunity?
A
T cells, B cells and circulating antibodies
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
5
Q
This is the mechanism of Resistance to adaptative immunity
A
Variation through V (D) J recombination during lymphocyte development
6
Q
In this immunity the microbial resistance is not heritable
A
Adaptative immunity
7
Q
The immune response to pathogen is nonspecific
A
Innate immunity
8
Q
How much time does it takes for Innate immunity to respond to pathogens?
A
Occurs rapidly (Minutes to hours)
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
10
Q
These are physical barriers for innate immunity
A
Epithelial tight juctions, mucus
11
Q
For innate immunity these are the secreted proteins
A
Lysozyme, complement, CRP, defensins
12
Q
Which are the secreted proteins for adaptative immunity?
A
Immunoglobulins
13
Q
Pattern recognition receptors that recognize pathogen- Associated molecular patterns (PAMPs)
A
Toll like receptors (TLRs)
14
Q
These are the key features in pathogen recognition for innate immunity
A
Toll like receptors (TLRs)
15
Q
Which are consider pathogen associated molecular patterns (PAMPs)?
A
LPS (gram negative bacterias)
Flagellin (bacteria)
ssRNA (viruses)
16
Q
For this immunity we find the pathogen associated molecular patterns (PAMPs)
A
Innate immunity
17
Q
Which cells manage the pathogen recognition for adaptative immunity?
A
Memory cells
18
Q
In adaptative immunity what are the memory cells?
A
Activated B and T cells
19
Q
How do Memory cells work?
A
Subsequent exposure to a previously encountered antigen→ Stronger immune response
20
Q
How encodes MHC?
A
HLA genes
21
Q
What is the function of MHC?
A
Present antigen fragments to T cells and bind TCRs
22
Q
How many types of MHC exist?
A
MHC I
MHC II
23
Q
Which are the loci for MHC I?
A
HLA-A, HLA- B, HLA-C
24
Q
These are the loci for MHC II
A
HLA-DR
HLA- DP
HLA- DQ
25
These are the sites where MHC I bind
TCR and CD8
26
For MHC II these are the binding sites
TCR and CD4
27
Whcih cells express MHC I?
On all nuclated cells
| Not expressed onRBCs
28
Who can express MHC II?
Only on APCs
29
Which is the function of MHC I?
Present endogenousky synthesized antigens (eg viral) to CD8+ cytotoxic T cells
30
How does MHC II works?
Present exogenously synthesized proteins (eg bactrerial proteins, viral capsid proteins) to T- helper cells
31
How are the antigen loaded for MHC I?
Antigen peptides loaded onto MHC I in RER after delivery via TAP peptide transporter
32
This is the way antigen load in MHC II
Antigen loaded following release ofinvariant chain in an acidified endosome
33
Who manages the mode of transport to cell surface in MHC I?
β2 microglobulin
34
Which HLA subtype is associated with Hemochromatosis?
A3
35
These diseases are associated to B27 HLA subtype
Psoriatic arhrhritis
Ankylosing spondylitis
Arthritis of inflammatory bowel disease
Reactive arthritis (formerly Reiter syndrome)
36
Which are consider seronegative arthropathies?
```
The ones associated to B27 subtype
Psoriatic arhrhritis
Ankylosing spondylitis
Arthritis of inflammatory bowel disease
Reactive arthritis (formerly Reiter syndrome)
```
37
These HLA subtypes are related to Celiac disease
DQ2/ DQ8
38
Which diseases are related to DR2 HLA subtype?
Multiple sclerosis, hay fever, SLE, Goodpasture syndrome
39
These diseases are related to DR3
Diabetes mellitus type 1, SLE, Graves disease
40
For DR4 HLA subtype these are the related diseases
Rheumatoid arthritis, Diabetes mellitus type 1
41
These health problems are related to DR5 subtype
Pernicious anemia → vitamin B12 deficiency, Hashimoto thyroiditis
42
Which cells are affected by Natural Killers?
Virally inffected cells and tumor cells
43
What is the effect of Natural Killers to Virally inffected cells and tumor cells?
Use perforin and granzymes to induce apoptosis
44
Who enhance the activity of Natural killers?
By IL-2, IL-12, IFN-β and IFN α
45
What induces the activity of Natural killers?
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
46
This is another mechanism of how Natural killers kills
Via antibody dependent cell mediated cytotocixity
47
How does Via antibody dependent cell mediated cytotocixity makes natural killer work?
CD 16 binds Fc region of bound Ig, activating the NK cell
48
Which are the three functions of B cells?
Recognize antigen
Produce antibody
Maintain immunologic memory
49
How do B cells recognize antigen?
Undergo somatic hypermutation to optomize antigen specificity
50
This is the way B cells produce antibodies
Differentiate into plasma cells to secrete specific immunoglobulins
51
How do B cells immunologic memory work?
Memory B cells persist and accelerate future response to antigen
52
These cells manage acute and chronic cellular organ rejection
T cells
53
Which is the function of CD4+ T cells?
Help B cells make antibody and produce cytokines to activate other cells of immune system
54
This is the function of CD8+ T cells
Kill virus-infected cells directly
55
Who manages delayed cell mediated hypersensitivity?
T cells
56
Which is the immunologic type related to cell mediated hypersensitivity?
IV
57
This MHC is related to CD4+ T cells
MHC II
58
Which T cells are related to MHC I?
CD8+ T cells
59
Where is produced T cell precursor?
Bone marrow
60
Which organ manages positive and negative selection of T cells?
Thymus
61
Which cells pass through positive selection?
Indiferentiated T cell CD4+ and CD8+
62
Where is carried the Positive selection of T cells?
Cortex of Thymus
63
Which cells can survive positive selection?
T cells expressing TCRs capable of binding surface sekf MHC molecules survive
64
This is the site for Negative selection of T cells
Medulla
65
What is the negative selection of T cells?
T cells expressing TCRs with high affinity for self antigens undergo apoptosis
66
Which is the differentiation procees of T cells
1º T cell precursor (Bone Marrow)
2º Positive selection (Cortex Thymus)
3º Negative selection (Medulla Thymus)
4º Action in lymph nodes
67
This is the effect of CD8+ T cells
Kills virus infected cells
Neoplastic cells
Donor graft cells
68
Which are the main differentiated T cell types of Helper T cell?
Th1 cell
Th2 cell
Th17 cell
T reg
69
Who stimulates Th1 cell conversion?
IL-12
70
This interleucin stimulates the conversion of CD4 T cell to Th2 cell
IL-4
71
Who stimulates Th17 cell conversion from T helpers?
TGF β + IL-6
72
Who stimulates T reg cell conversion from T helpers?
IL-6
73
This is another name for CD4 T cell
Helper T cell
74
Who are consider Antigen presenting cells (APC)?
B cells
Macrophages
Dendritic cells
75
Which are the two signals require to activate T cells?
B cell activation
| Class swithching
76
Which is the procces of NAive T cell activation?
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
Which is the mechanism of B cell activation and class swithching?
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
Which are the two main groups of Helper T cells?
Th1
| Th2
79
What does Th1 secretes?
IFN γ
80
Which cells can be activated by Th1?
Macrophages and cytotoxic T lymphocytes (CTLs)
81
Who inhibits Th1 cell?
IL-4 and IL-10
82
Who produces IL-4 and IL-10 that inhibits Th1 cell?
Th-2
83
Which interleucins are secreted by Th-2?
IL-4, IL-5, IL-6, IL-13
84
Which is the funtion of TH2 cell?
Recruits eosinophils for parasite defense and promotes IgE production by B cells
85
Who can inhibit Th-2?
Inhibited by IFN-γ (from Th1 cell)
86
How does Macrophage- lymphocyte interaction works?
Macrophage release IL-12, which stimulates T cells to differentiate into Th1 cells. Th1 cells relase IFN γ to stimulate macrophages
87
Who binds MHC II on APC?
Helper T cell have CD4
88
How does Cytotoxic T cells kill virus infected, neoplastic and donor graft cells?
Indcuing Apoptosis
89
This is the mechanism of action of Cytotoxic T cells
Release cytotoxic granules containing preformed proteins
90
Which are preformed proteins produced by Cytotoxic T cells?
Perforin
Granzyme B
Granulysin
91
Which is the function of perforins?
Helps deliver the content of granules into target cell
92
What is the Granzyme B?
A serine protease, activates apoptosis inside target cell
93
This is how Granulysin work
Antomicrobial, induces apoptosis
94
Binds to MHC I on virus infected cells
Cytotoxic T cells have CD8
95
Which is the function Regulatory T cells?
Help maintain specific immune tolerance by suppressing CD4 and CD8 T cell effector function
96
Who identifies Regulatory cells?
Expression of cell surface markers CD3, CD4, CD25 (α chain of IL-2 receptor) and transcription factor FOXP3
97
What do Activated regulatory T cells produce?
Anti-inflamatory cytokines like IL-10 and TGF β
98
In Antibody structure who recognizes antigens?
Variable part of L and H chains
99
Who fixes complement?
Fc portion of IgM abd IgG
100
Who contributes fo Fc and Fab fractions?
Heavy chain contributes
101
Who contributes only to Fab fraction?
Light chain
102
What is the purpose of Fab fragment?
Antigen-binding fragment
103
What does Fab fragment identifies?
Determines idiotype: unique antigen binding pocket
104
How many antigens can a B cell expressed?
Only 1 antigen expressed per B cell
105
Which are the characteristics of Fc fraction?
Constant
Carboxyl terminal
Complement binding
Carbohydrate side chains
106
What does Fc fraction determines?
Determines Isotype (IgM, IgD, etc)
107
Who generates antibody diversity?
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
Which are the light chains?
V (D)J genes
109
This is the light chain
VJ genes
110
When does the Somatice hypermutation happens?
Following antigen stimulation
111
What happens during the opsonization?
Antibody promotes phagocytosis
112
What happens in the neutralization by antibodies?
Antibody prevents bacterial adherence
113
What is the relationship of Antibodies and Complement?
Antibodies activate complement, enhancing opsonization and lysis
114
Which are the immunoglobulin isotypes?
```
IgG
IgA
IgM
IgD
IgE
```
115
Which are the immunoglobulin isotypes expressed by mature lymphocytes on their surfaces?
IgM and IgD
116
Where do B lymphocytes diffetentiate?
Germinal centers of lymph nodes by isotype switching
117
What is isotype switching?
Gene rearrangement; mediated by cytokines and CD40 ligand
118
What is the product of Isotype switching of B lymphocytes?
Plasma cells that secrete IgA, IgE or IgG
119
Main antibody in secondary (delayed) response to an antigen
IgM
120
Which is the most abundant immunoglobulin isotype in serum?
IgM
121
Which are the main functions of IgM?
Fixes complement, crosses the placenta, opsonizes bacteria, neutralizes bacterial toxins and viruses
122
This immunoglobulin isotype crosses placenta providing infants with passive immunity
IgM
123
Prevents attachment of bacteria and viruses to mucous membranes
IgA
124
Does IgA fixes complement?
No
125
Which are the forms of IgA?
Monomer
| Dimer
126
When is presented IgA monomer and when dimer?
IgA monomer in circulation
| IgA dimer when secreted
127
How does IgA crosses epithelial cells?
By transcytosis
128
Which is the most produced antibody overall?
IgA
129
Where can we find IgA?
In secretions (tears, salivan mucus) and early breast milk
130
What name does early breast milk receives?
Colostrum
131
What does IgA does before secretion?
Picks up secretory component from epithelial cells
132
Immunoglobulin isotype produced in the primary (immediate) response to an antigen
IgM
133
Which are the alternative names to antigen for response?
Primary (immediate)
| Secondary (delayed)
134
Which is the function of IgM?
Fixes complement but does not cross the placenta
135
Where is located IgM?
Antigen receptor on to the surface of B cells
136
Which are the forms of IgM? When can we find each form?
Monomer on B cell
| Pentamer when secreted
137
Which is benefeat of pentamer shape of IgM?
Allows it to efficiently trap free antigens out of tissue while humoral response evolves
138
Which Immunoglobulin isotypes does not cross the placenta?
IgM and IgA
139
This Immunoglobulin isotype crosses placenta
IgG
140
Which is the function of IgD?
Unclear function
141
Where is IgD found?
Surface of many B cells and in serum
142
This Immunoglobulin isotype has the lowest concentration in serum
IgE
143
Which are the functions of IgE?
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
How does IgE mediates immunity to worms?
By activating eosinophils
145
Which reaction does IgE mediates?
Immediate hypersensitivity (Type I)
146
How are classified Antigens types?
Thymus independent antigens
| Thymus dependent antigens
147
Which antigens are classified as Thymus independent antigens?
Antigens lacking a peptide component
148
Give an example of Antigens lacking a peptide component
Lipopolysaccharides from gram negative bacteria
149
Which is the characteristic of Thymus independent antigens?
Cannot be presented by MHC to T cells
150
How immunogenic are Thymus independent antigens consider?
Weakly or nonimmunogenic
151
What do Vaccines require in Thymus independent antigens?
Require boosters (eg pneumococcal polysacharide vaccines)
152
What are the Thymus dependent antigens?
Antigens containing a protein component
153
Which vaccine is an example of antigen containig a protein component?
Diphteria vaccine
154
When does the class switching and immunologic memory occurs in Thymus dependent antigens?
Occurs as a result of direct contact of B cells with Th cells (CD40-CD40 ligand interaction)
