456 Flashcards
(111 cards)
1
Q
immunity biologically is
A
resistance to pathogens
2
Q
immune system
A
The collection of cells, tissues, and molecules that mediate reactions
3
Q
immune response
A
coordinated response of the immune system to pathogens and other substances
4
Q
What consequence does the immune systems defense against infections have
A
Deficient immunity results in increased liability to infections eg: AIDS
5
Q
Vaccination function
A
Boosts immune defenses and protects against infections
6
Q
Defense against tumors implies
A
Potential for immunotherapy of cancer
7
Q
Control of tissue regeneration and scarring leads to
A
Repair for damaged tissues
8
Q
The immune system causes allergies, autoimmune and inflammatory diseases, why?
A
Because it can injure cells and induce pathological inflammation
9
Q
Host defenses are divided into
A
Innate immunity
Adaptive immunity
10
Q
…… provides immediate protection against microbial invasion,
A
Innate immunity
11
Q
….. develops slowly and provides more specialized defense against infections
A
Adaptive immunity
12
Q
Adaptive immunity is split into
A
Humoral immunity
Cell mediated immunity
13
Q
How are extracellular microbes fought off in the adaptive immunity
A
By humoral immunity:
The responding lymphocytes in B lymphocyte and its mechanisms is secretion of antibodies.
14
Q
Functions of b lymphocytes
A
Produce antibodies which block infections and eliminate extracellular microbes
15
Q
How are phagocytosed microbes in the macrophages fought off
A
Cell mediated immunity:
Responding lymphocyte: helper T lymphocyte it’s mechanism is secretion of cytokines in activated macrophages
16
Q
Purpose of helper T lymphocyte
A
Elimination of phagocytosed microbes
17
Q
How are intracellular microbes which replicate within the cell (eg: virus) fought off in the innate immune system
A
Cell mediated immunity: responding lymphocyte: cytotoxic T lymphocyte.
18
Q
Functions of cytotoxic t lymphocytes
A
Kill infected cells and eliminate reservolrs of infection
19
Q
Humoral immunity
A
combating pathogens via antibodies, which are produced by B cells and can be found in bodily fluids.
20
Q
Antibodies can be transferred between individuals, why?
A
to provide passive immune protection
21
Q
Cell-mediated immunity
A
the work of pathogen- specific T lymphocytes, which can act directly to eradicate the infectious agent as well as aiding other cells in their work.
22
Q
Properties of adaptive immune responses
A
Specificity Diversity Memory Clonal expansion Specialization Contraction and homeostasis Non reactive to self
23
Q
Specificity in adaptive immunity
A
Ensures that immune responses are precisely targeted to microbial pathogens
24
Q
Diversity in adaptive immunity
A
Enables immune system to respond to a variety of antigen
25
Memory in adaptive immunity
Leads to enhanced responses to repeated exposure to the same antigen
26
Clonal expansion in the adaptive immunity
Increases number of antigen specific lymphocytes from a small number of naive lymphocytes
27
Specialization in adaptive immunity
Generates responses that are optimal for defense against different types of microbes
28
Contraction and homeostasis in immunity
Allows immune system to respond to newly encountered antigens
29
Nonreactivity to self in adaptive immunity
Prevents injury to the host during responses to foreign antigens
30
All lymphocytes arise from
Common lymphoid precursor cells in the bone marrow
31
Where do B &T lymphocytes mature
B lymphocytes mature in the bone marrow, and T lymphocytes mature in the thymus
32
After maturing in the bone marrow, b lymphocytes are ....., but t lymphocytes are...
Immature B lymphocytes
| Naive T lymphocytes
33
After maturing, B & T lymphocytes go to
Blood lymph
34
After the blood lymph, naive T lymphocytes and immature B lymphocytes go to
the peripheral (secondary) lymphoid organs like lymph nodes, spleen, and mucousal cutaneous lymphoid tissues.
35
After going to the secondary lymphoid organs, B and T cells are ............ as ....
Recirculated to blood lymph
| Mature naive B lymphocytes and naive T lymphocytes
36
What are the generative lymphoid organs
Thymus
| Bone marrow
37
The common portals of entry for microbes are
the skin and gastrointestinal, respiratory, and genitourinary tracts
38
Antigen-Presenting Cells
specialized cells located in the epithelium of common portals of entry for microbes that capture antigens, transport them to peripheral lymphoid tissues, and display (present) them to lymphocytes.
39
APC
Antigen presenting cells
40
Phases of adaptive immunity
Activation phase
| Effector phase
41
Examples of APC
macrophages, dendritic cells, and b-cells
42
Talk about the activation phase
1. An invading bacteria is phagocytized by an APC
2. Lysosomes containing digestive enzymes combines with the phagosome to process the antigens
3. Processed in tissues combined with the MHC class ll proteins and are presented on the surface of the APC
4. Helper T cells recognize the displayed antigen on the APC and bind to the MHC class II-antigenic peptide complex
5. The binding of helper T cells triggers the APC to release the cytokine IL-1 which activates the helper T cell.
6. activated helper T cells release the cytokine IL-2 which stimulates the T cell to proliferate
7. Many helper T cells are produced each with a receptor specific for the original antigen
43
Cd4+
Helper T cells
44
Function of MHC class ll
The main function of major histocompatibility complex (MHC) class II molecules is to present processed antigens
45
What is MHC
major histocompatibility complex
46
Effector phase in adaptive immunity
1. Begins when a B cell that exhibits on its surface an Ig receptor specific for the same antigen originally engulfed by the APC encounters and binds the antigen.
2. B cell engulfs the complex by receptor-mediated endocytosis.The phagosome containing the antigen fuses with a lysosome.The antigen is processed.
3. The processed antigen binds to the MHC class ll protein and is displayed on the surface of the B cell.
4. Helper T cells bind to displayed on the surface of the cell causing the helper T cell to release cytokine IL2
5. Cytokine stimulate the B cell to divide and proliferate into identical B cells
6. B cells differentiate into antibody producing cells and memory cells
7. Plasma cells release antibodies with a specification identical to that in the surface receptors of the B cells that carries out the goal of fighting the invaders.
8. Antibodies bind in a lock and key fashion to the antigen on the surface of the original bacterial invader which make it easier for killer cells to phagocytose and complement system punctures holes in the bacteria.
47
Plasma cells are
differentiated B-lymphocyte capable of secreting immunoglobulin, or antibody
48
Immunoglobulin is
Antibodies
49
After maturation of b lymphocytes in the bone marrow these cells are released into
the blood and they keep recirculating between lymph, blood and secondary lymphoid tissues
50
B cells are differentiated into
Mature B cells that recognize the antigen through their BCR.
Effector B cells
(Antibody secreting cells)
51
Effector B cells are called
Plasma Cells
52
BCR
B cell Receptors
53
Antibodies
circulating proteins that are produced in vertebrates in response to exposure to foreign structures known as antigens, cand are the mediators of humoral immunity against all classes of microbes.
54
Ig
Immunoglobulin
| Antibody
55
What does the term immunoglobulin refer to
the immunity-giving portion of the globulin fraction of serum or plasma
56
Antigens
substances that stimulate production of antibodies
57
Plasma
liquid, cell-free part of blood, that has been treated with anti-coagulants and contains clotting factors like fibrinogen
58
Cogulate
change to a solid or semi-solid state.
59
Plasma =
Serum + clotting factors
60
Serum
Liquid part of blood after you leave the blood to coagulate ( no anti coagulants added). It doesn’t contain any clotting factors (fibrinogen)
61
antiserum
serum sample that contains detectable antibody molecules that bind to a particular antigen
62
serology
The study of antibodies and their reactions with antigens.
63
All antibody molecules share the same .......but display remarkable variability in .......
basic structural characteristics
| the regions that bind antigens.
64
Antibodies belong to what fraction of proteins and are what
gamma globulin fraction
| Glycoproteins
65
Glycoproteins
proteins which contain oligosaccharide chains covalently attached to amino acid side-chains.
66
Basic structure of antibody resembles a
Y shape
67
What are the 2 forms of antibodies
Membrane-bound antibodies
| Secreted antibodies
68
Membrane-bound antibodies are found in ... and function as ......
surface of B lymphocytes
antigen receptors
69
Secreted antibodies are found in ...... and their function is .......
the plasma, in mucosal secretions, and in the interstitial fluid of tissues.
protect against microbes
70
Structure of an antibody molecule
An antibody molecule has a symmetric core structure composed of two identical light chains and two identical heavy chains.
71
Antibodies can be single molecules like .....
| Double like .... or in groups of 5 like....
IgD, IgE, IgG
IgA
IgM
72
The lower part of antibodies is called the ......... and the upper part is called........
```
Fc region ( fragment crystalizable)
Fab region (fragment antigen binding)
```
73
The heavy chain consists of
3 constant domains and 1 variable domain
74
The light chain consists of
1 constant domain and 1 variable domain
75
The amino-terminal variable definition and function
The variable domains of the heavy and light chains (VH and VL)
participate in antigen recognition
76
carboxy-terminal constant (C) regions definition and function
```
the Constant (C) regions of the heavy and light chains
C regions of the heavy chains that help mediate some of the effector functions of antibodies.
```
77
IgM is a ........... antibody but IgG is a ...... antibody
| Secreted or membrane
Membrane
| Secreted
78
IgG has ... constant domains in the heavy chain but IgM has .....
3
| 4
79
What is a domain
series of repeating homologous structural units, each about 110 amino acid residues in length, that fold independently in a globular motif
80
Light chains have a molecular weight of...... and contains...... amino acids
25 kilo dalton
| 220
81
There are two classes, or isotypes, of light chains, called
kappa (κ)
| Lambda (λ)
82
Each antibody molecule has either
two identical κ light chains or two identical λ light chains but never one and the other
83
κ chains are encoded on chromosome ...but λ chains are encoded on ....
2
| 22
84
The longer subunits of Antibodies structure
Heavy chains
85
Each heavy chain has a molecular weight of .... and has ..... amino acids
50-70 kilo dalton
| 440 amino acids
86
There are ..... types or classes of heavy chains in humans, all encoded chromosome .....
5
| 14
87
The classes of antibody molecules are also called....... and are named......
isotypes
| IgA, IgD, IgE, IgG, and IgM
88
```
What heavy chain does each antibody have?
IgA1
IgA2
IgD
IgE
```
α1(alpha 1)
α2
δ (beta)
ε
89
What heavy chain does each antibody have?
IgG1, IgG2, IgG3, IgG4
IgM
γ1, γ2, γ3, γ4
| μ
90
Variable regions VRs
first 110 amino acids of the N-terminal regions of both light and heavy chains.
91
amino acids sequences (ترتيبهم يعني) in variable regions has
great variability that’s precisely organized
92
CDRs
Complementarity Determining Regions alsp known as hypervariable regions
93
There are ..... CDRs in each variable region and they are designated as ........
3
| CDR1, CDR2, CDR3
94
Each CDR is ..... amino acids long
10
95
How many CDRs in an antibody
12
96
Framework Residues
Intervening sequences between the CDRs
97
FRs
Framework residues
98
How many constant regions in heavy chains
3-4
99
What forms the basis of antibody classification
Heavy chains
100
Proteolytic treatment of immunoglobulin with 2 enzymes and they are
Papain
| Pepsin
101
Papain acts on what area and how does it cleave igG
Hinge region just before the disulfide bond
| It cleaves it into 3 separate pieces (FAB, FAB, FC)
102
Why is FC (fragment crystallizable) named that way
Because when treated by papain in has the tendency to self associate and crystallize into a lattice.
103
Pepsin acts on what area and how does it cleave igG
the distal hinge region and cleaves the IgG into two parts, generating a F(ab′)2 fragment of IgG with the hinge and the interchain disulfide bonds intact and two identical antigen- binding sites and the other part is just peptide fragments.
104
Antibody-mediated effector functions
1. Neutralization of microbes or toxic microbial products
| 2. Recruiting effector cells and molecules to kill the pathogens
105
How do antibodies aid in Recruiting effector cells and molecules to kill the pathogens
1. Activation of the complement system
2. Opsonization of pathogens for enhanced phagocytosis
3. Antibody-dependent cell-mediated cytotoxicity, by which antibodies target infected cells for lysis by cells of the innate immune system
4. Antibody-mediated mast cell activation to expel parasitic worms.
106
Neutralization in antibodies is
Blocking the pathogen from entering the cells
107
How does neutralization occur
Antibodies bind to their specific microbes or microbial toxins, then block the pathogens entry into the host cell and neutralize
their infectivity
108
How do microbes cause disease
by binding to the surface molecules of the host cell.
109
Purpose of opsonization
Enhances the process of phagocytosis
110
Antibodies coat the surface of the pathogen by
binding to specific antigenic determinants.
111
Phagocytic cells have...... on their surface.
specific FC receptors
