IMMUNOLOGY Flashcards
1
Q
What occurs at the Primary Lymphoid Organs
A
Sites where stem cells divide and immune cells develop
2
Q
What occurs at the Secondary Lymphoid Organs
A
Sites where most immune responses occur
3
Q
Primary Lymphoid Organs
A
- Bone Marrow (Yolk Sac and Fetal Liver in Embryo)
- Thymus
4
Q
Secondary Lymphoid Organs
A
- lymph nodes
- spleen
- lymphoid nodules
5
Q
Bone Marrow site where
A
B-cells mature
6
Q
Thymus site where
A
T cells mature
Atrophies after maturity
7
Q
The thymus contains what types of cells
A
Contains T cells, scattered dendritic cells, epithelial cells, and macrophages
8
Q
Produced in the bone marrow
A
Blood cells are produced here: B-cells and Immature T-cells
9
Q
Yolk Sac and Fetal Liver produces
A
Blood cells are produced here in the embryo
10
Q
Lymph nodes
A
Secondary Lymphoid Organ: Scattered throughout the body Filter microbes Macrophages in nodes phagocytize microbes that pass through in the lymph fluid
11
Q
Spleen
A
Secondary Lymphoid Organ:
Largest lymphoid organ
Removes microbes and dead or old erythrocytes
12
Q
Lymphoid Nodules
A
Secondary Lymphoid Organ:
Tonsils
Peyer’s Patches and MALT (Mucosal-Associated Lymphoid Tissues) Appendix
13
Q
Immune Cells Travel in the ____ and _______
A
Immune Cells Travel in the Blood and Lymphatic Vessels
14
Q
Immune Cells are
A
White Blood Cells/Leukocytes
15
Q
Produced from lymphoid stem cells
A
Lymphocyte
- T cells
- B cells
- NK cells
16
Q
Produced from myeloid stem cells
A
Erythrocyte Neutrophil Monocyte Eosinophil Basophil Megakaryocyte (platelets(
17
Q
Megakaryocyte produce
A
platelets
18
Q
myeloid cells
A
Neutrophil
Monocyte
Eosinophil
Basophil
19
Q
Macrophages and dendritic cells are
A
monocytes
20
Q
Eosinophils
A
Destroy parasites
21
Q
Basophils
A
Release a variety of chemicals Histamine, leukotrienes, prostaglandins
22
Q
Mast Cells
A
Release chemicals, histamine
23
Q
Neutrophils
A
Phagocytes
24
Q
Monocytes
A
Macrophages and Dendritic Cells Phagocytes
25
Lymphocytes
B lymphocytes
| T lymphocytes
26
T lymphocytes
TH and TC
27
Antigen
1. Immunogen – material that induces an immune response 2. Hapten (+ Carrier = Immunogen)
3. Allergen
4. Tolerogen
5. Ligand
28
Non-specific/Innate Immunity
Ability of the body to defend against microbes and other foreign substances - without recognition of the invading pathogen.
29
First Line of Defense
Physical Barriers
30
Second Line of Defense
Cellular Factors
| Humoral Factors
31
Physical Barriers
```
Skin
Mucus
Hair
Cilia
Sebum
Lysozyme
Gastric
Juice
```
32
Innate Immunity
No memory
33
Cellular Factors (2nd Line of Defense)
- Phagocytic Cells
neutrophils, macrophages, dendritic cells
- Cells with inflammatory mediators basophils, mast cells, eosinophils
- Natural Killer Cells
34
Humoral Factors (2nd Line of Defense)
- Inflammation and Fever
- Antimicrobial Substances
Acute Phase Reactants: C-Reactive Protein, Complement, Interleukin and Cytokines
- Interferon-alpha
35
Non-Specific Response to Tissue Damage
Inflammation
36
4 Distinct Signs and Symptoms of Inflammation
Redness
Heat
Pain
Swelling
37
3 Stages of Inflammation
1. Vasodilation*
2. Emigration of Phagocytes
3. Tissue Repair
38
Vasodilation
* Widening of blood vessels allows more blood flow to the site
* Increased permeability of capillaries allows substances to go to the damaged site
39
Antimicrobial Substances
Discourage Microbial Growth or Spread of Pathogen
40
Interferons
Binds to receptor on cells and sends signal to to activate genes for antiviral protien
41
Type I interferon
Prevents viral replication
42
Complement
a group of plasma proteins
43
Complement Protein Function
A large family of plasma proteins with multiple functions. 30 different proteins participate in the cascades.
A central protein in the complement cascade is C3.
44
A central protein in the complement cascade is
C3
45
Function of Complement C3b
As an opsonin
| Binds to phagocytes via the C3b receptor
46
Natural Killer Cells
a class of lymphocytes, similar to cytotoxic T cells, who target virus-infected cells and cancerous cells
47
T/F: Natural Killer Cells attack and kill these target cells without binding to them.
F: they attack and kill these target cells directly after binding to them.
48
Natural Killer Cells are/are not antigen-specific
are not
| NK cells do not need to recognize a specific antigen.
49
The similarity between cytotoxic T cells and NK cells
Like cytotoxic T cells, they attack and kill these target cells directly after binding to them.
50
How do NK cells kill body cells?
Release chemicals that lead to death of infected or abnormal body cells*
Release Perforin and granzyme
51
The difference between cytotoxic T cells and NK cells
Unlike cytotoxic T cells, they are NOT antigen-specific. NK cells do not need to recognize a specific antigen.
52
Perforin
polymerize and form a channel in target cell membrane
53
What do NK cells recognize on the cells
*Cells not expressing MHC-I
Virally-infected
or cancerous cells down-regulate MHC-1
54
What cells express MHC-I on their surface?
every nucleated cell in the body
55
Granzymes
induce programmed cell death (apoptosis) in the target cell
56
Phagocytes
Non-specifically engulf microbial invaders
57
Types of Phagocytes
Fixed-Tissue Macrophages Neutrophils
| Monocytes – Macrophages and Dendritic Cells
58
Phagocytosis steps
Steps: Adherence, Ingestion, Digestion, Killing
- Microbe
- Endocytosis
- phagosome formation
- Lysosome fusion with the phagosome
- Phagolysosome
- Release of end products into or out of the cell
59
How Does the Phagocyte Recognize Microbes?
Detect unique, conserved proteins that are essential to microbial
physiology (molecular signatures of infection)
• Pathogen-Associated Molecular Patterns(PAMPs)
60
PAMPS are recognized by
Immune system receptors called pattern recognition receptors (PRR), including Toll-Like Receptors
61
Toll-Like Receptors
A family of highly conserved transmembrane receptors Essential for microbial recognition via PAMPs
• Extracellular domain for recognition of pathogens
• Intracellular signalling domain
62
Emigration of Neutrophils (phagocytes)
Chemotaxis
Margination –
Diapedesis –
63
Chemotaxis
Chemically stimulated movement of phagocytes
64
Chemoattractants
Chemicals that attract phagocytes
65
Margination
Migration of phagocyte towards the tissue injury
66
Diapedesis
Phagocytes move across the capillary wall
67
Specific Role of Neutrophils in Inflammation
Neutrophils Die in the Process of Killing Bacteria
68
NETs – Neutrophil Extracellular Traps
are made of processed chromatin bound to granular and selected cytoplasmic proteins which come from the lysed neutrophils
69
Pus
a mixture of dead bacteria and neutrophils
70
Link Innate and Adaptive Immunity
Antigen-presenting cells
| via Antigen Presentation by Phagocytes
71
Specific/Adaptive immunity mediated by
Antibodies or cells
72
Humoral Specific/Adaptive Immunity
Antibody-Mediated
Immunity Involves the use of B cells
Transform into plasma cells and memory cells Synthesize and secrete antibodies
73
Involves the use of cytotoxic T cells
| Kill infected body cells, cancer cells, foreign cells
Cell-Mediated Specific/Adaptive Immunity
74
Two molecular classes of MHC
MCHI
| MCHii
75
chance of identical MHC
1 in 5 million `
76
Only people that have the same MHCs on their cells
identical twins
77
MHC molecules structure
2 chains – alpha and beta
78
MHC-I are on
all nucleated cells
79
MHC-II are on
on all antigen-presenting cells
- macrophages
- dendritic cells
- B cells
80
antigen-presenting cell types
– Dendritic cell / Professional APC
– Macrophage
– B lymphocyte (B cell)
81
Cells that have no MHCs on their surface
*erythrocytes have no MHCs on their surface
82
T-cell receptors recognize
antigens only when they are associated with specific MHC proteins
83
Antigen Presenting Cells (APCs) present
Exogenous Antigens with MHC-II
84
Steps of Antigen Presenting Cells
STEPS:
• Ingest antigen
• Digestion into peptide fragments
• Synthesize and package MHC-II molecules
• Bind peptide fragments to MHC-II
• Insert antigen–MHC-II complexes on plasma
membrane
85
Antigen
antibody generator
86
Epitope
The part of the antigen that is recognized by the immune cells
87
Characteristics of an antigen:
Reactivity - Antibody binds specifically to the antigen that provoked it
Immunogenicity - Ability to provoke an immune response by stimulating antibody production
88
Adaptive Immune Response
Acquired, Specific
89
Innate or Adaptive: Antigen (and epitope) specific
Adaptive Immune Response
90
Innate or Adaptive: Antigen-presenting cells (APC) – (MHC-II + peptide)
Adaptive Immune Response
91
Innate or Adaptive: The ability of the body to defend against specific microbes and foreign substances – Involves MEMORY for previously encountered antigens
Adaptive Immune Response
92
Adaptive Immune Response Cells involved
B Cells and T Cells are involved
93
Must recognize the specific foreign material to be attacked
B and T Lymphocytes
94
Any molecule that can trigger an adaptive immune response against itself or the cell bearing
Antigen
95
three stages of adaptive immune response
The encounter and recognition of an antigen by lymphocytes Lymphocyte activation
The attack launched by the activated lymphocytes and their secretions
96
Origins of B Cells and T Cells
Bone marrow
97
Where T cells mature
Thymus
98
Where B cells mature
Bone marrow
99
The first cell to show specificity
Helper T cell
100
Co-Reception occurs between
B7 - CD28
101
B7
on the antigen-presenting cell
102
CD28
on T helper cell
103
What results from the displacement of CD28 from B7 by CTLA4 and PD-1
Biological process that shut off the T cell activation
results in T cell inactivation
104
Bacterial Infection leads to
antibody synthesis in secondary lymphoid organs
105
Creates specific antibodies
Plasma Cells
106
Macrophages and B cells Process and Present Antigen to a
Helper T cell
107
CD4
co-receptor for the T-cell receptor
108
Three Events Required for the Activation of Helper T Cells
1. MHC-II + Peptide – TCR 2. Co-reception CD28 – B7 3. Cytokines from APC
stimulate TH Cell
109
B cells that secrete antibodies
Plasma cells
110
B cells that are long-lived and are used for memory
Memory B cells
111
Which plasma protein increases during infection
gamma globulins
112
Antibody Structure
Contain four polypeptide chains
- Two Heavy chains that are Identical to each other
- Two Light chains that are Identical to each other
Flexible hinge region
113
Variable region on an antibody
Antigen binding site
114
Constant region on an antibody
Same in all antibodies of a class
115
Types of antibody class:
* IgG
* IgA
* IgM
* IgD
* IgE
116
IgG
most common type of antibody
| protect you against infection
117
IgA
to protect the mucosal tissues from microbial invasion
118
IgM
the largest antibody
| first line of host defense against infections
119
IgD
function unclear
120
IgE
critical role in the allergic inflammatory process
| allergic reactions
121
____ cells will secrete specific antibodies
Plasma cells will secrete specific antibodies
122
_____ cells which allow faster response if antigen is seen again
Memory cells which allow faster response if antigen is seen again
123
B cells become activated in the _____
B cells become activated in spleen, lymphoid nodule, or lymph node
124
B cells are activated in presence of
B cells become activated in the presence of a microbe
125
Antibodies can be acquired actively/passively or both
Can be Actively or Passively Acquired
126
Active Antibody Immunity
The person’s own immune system responds to microbe Long-lasting Protection – Memory Cells are involved
127
Passive Antibody Immunity
The person receives antibodies from another person or animal Temporary Protection - NO Memory Cells are involved
128
Active Natural Immunity
Develops when a person is exposed to an antigen by chance
129
Active Artificial Immunity
Develops when a person is purposefully exposed to an antigen
130
Passive Natural Immunity
IgG from mother to fetus across the placenta IgA in Breast milk
131
Passive Artificial Immunity
Receive serum containing antibodies
| From person or animal that has been vaccinated
132
Flu virus
Active Natural
133
Flu vaccine
Active Artificial
134
A vaccine
may consist of small quantities of living or dead pathogens, small quantities of toxins, or harmless antigenic molecules derived from the microorganism or its toxin.
135
Resistance built up as a result of the body’s contact with microorganisms, their toxins or other antigenic components (from an infection or vaccine)
Active Immunity
136
The direct transfer of antibodies from one person to another
Passive Immunity
137
antibody-synthesizing capacity of infants
relatively poor
138
Antibody Functions
Antigen Neutralization Antigen Agglutination Antigen Precipitation Activating Complement Opsonization
139
Neutralizing Antigen
Binding to bacterial toxins
140
Agglutinating Antigen
Grouping of microbes with antigens
141
Precipitating Antigen
Linkage of soluble antigen
142
Activating Complement
Compliment protein becomes active when bound to antibody with microbe
143
Activation of Classical Complement Pathway
C1 binds to antigen binding site, and the C3b on the bacterium binds to the phagocyte
144
Opsonization
Direct Enhancement of Phagocytosis by Antibody
145
Rate of Antibody Production Following Initial Exposure to an Antigen and Subsequent Exposure to the Same Antigen
At the second antigen exposure, the Antibody concentration is much greater
146
Immune Memory Prevents
Disease
147
CD8 cells
Cytotoxic T cells
148
CD4 cells
Helper T cells
149
Lymphocytes Must Gain
Immunocompetence - Develop Antigen Receptors
150
Immunocompetence
Develop Antigen Receptors
151
The body will/will not create antibodies to antigens on your own cells
Will NOT
152
T helper cells are required to activate
B and Cytotoxic T cells
153
Terminal deoxynucleotidyl Transferase
inserts N-nucleotides to J gene segment during rearrangements of genes
Increases specificity
154
Antibody Classes is determined by
constant region
155
Primary response by antibody (antibody type and concentration)
IgM initially and then IgG is produced
156
Secondary response by antibody (antibody type and concentration)
IgM and IgG is produced, IgG is produced in a higher concentration
157
Amplification is due to
production of memory cells
158
T cells
- Used in cell-mediated immunity to eliminate specific antigens
- Require Activation - they are usually inactive
- Become activated only when they bind to a foreign antigen
159
T cells that don't recognize MHC Class II molecules are of
no value and are negatively selected (the clone is destroyed)
160
T cells that recognize MHC class II- self peptide complexes are
negatively selected (the clone is destroyed)
161
Development of Immune Tolerance develops during
Immune tolerance develops during fetal and early postnatal life
162
Immune tolerance develops due to
clonal deletion or clonal inactivation of cells that match body antigens
163
Endogenous Antigen
Digestion of antigen – virus - into peptide fragments
164
Steps of Infected Body Cells
Synthesis of MHC-I molecules
Binding of peptide fragments to MHC-I molecules.
Packaging of antigen–MHC-I complexes
Insertion of antigen–MHC-I complexes into the plasma membrane.
165
Steps of Antigen Presenting Cells
Synthesis of MHC-II molecules
Binding of peptide fragments to MHC-II molecules.
Packaging of antigen–MHC-II complexes
Insertion of antigen–MHC-II complexes into the plasma membrane.
166
Infected Cells Process and Present
Viral Antigens to a Cytotoxic T Cell
167
Killing of Virus-Infected Cells is done by
Cytotoxic T cells
168
Cytotoxic T cells release _______
perforin + granzymes
169
perforin
perforin facilities entry of cytotoxic Granzymes into cell
170
Granzymes
inducing apoptosis
| virus cannot replicate and is released
171
What does Antigen-MHC-I complex bind to
TCR
172
Factors that Alter Resistance to Infection
• Protein–calorie malnutrition
worldwide, the greatest contributor to decreased resistance to infection
• Preexisting disease, infectious or noninfectious, can predispose the body to infection
• Stress and state of mind can enhance or reduce resistance to infection (and cancer)
• Modest exercise and physical conditioning have net beneficial effects on the immune system and on host resistance
• Sleep deprivation is associated with decreased immune function
173
Immunodeficiency Diseases
Result from weak, underactive, or impaired immune systems
174
𝑺𝑪𝑰𝑫 = 𝑺𝒆𝒗𝒆𝒓𝒆 𝑪𝒐𝒎𝒃𝒊𝒏𝒆𝒅 𝑰𝒎𝒎𝒖𝒏𝒐𝒅𝒆𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝑫𝒊𝒔𝒆𝒂𝒔𝒆
a group of related diseases that arise from an absence of both B and T cells and, in some cases, NK cells
175
𝑨𝑰𝑫𝑺 = 𝑨𝒄𝒒𝒖𝒊𝒓𝒆𝒅 𝑰𝒎𝒎𝒖𝒏𝒐𝑫𝒆𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝑺𝒚𝒏𝒅𝒓𝒐𝒎𝒆 affects which cells
infects and kills helper T cells resulting in impaired immune responses to other infectious organisms.
176
Harmful Immune Responses
Graft Rejection
Transfusion Reactions
Allergy (Hypersensitivity) Autoimmune Disease
Excessive Inflammatory Responses
177
Tissue Grafts and Organ Transplantation
Class I MHC proteins on the graft cells and class II MHC proteins on the macrophages differ from the recipient
Consequently, the MHC proteins are recognized as foreign by the recipient’s T cells.
Cells bearing these proteins are destroyed by the recipient’s cytotoxic T cells with the aid of helper T cells.
Tools aimed at reducing graft rejection include radiation and drugs that kill actively dividing lymphocytes and thereby decrease the recipient’s T-cell population.
178
cyclosporine
blocks the production of IL-2 and other cytokines by helper T cells. This eliminates a critical signal for proliferation of both the helper T cells and the cytotoxic T cells.
179
Transfusion Reactions
illness caused when erythrocytes are destroyed during blood transfusion
180
Antibody of A blood type
Anti-B
181
Antibody of B blood type
Anti-A
182
Antibody of AB blood type
Neither Anti-A nor Anti-B
183
Antibody of O blood type
Both Anti-A and Anti-B
184
Allergic Reactions
When a person is overly reactive to a substance that most others tolerate well
185
Two types of allergic responses
- Immediate Hypersensitivity
| Delayed Hypersensitivity - Appears 12-72 hours after allergen exposure
186
Anaphylaxis
large amounts of the chemicals released by the mast cells (or blood basophils) enter the circulation, systemic symptoms may result and cause severe hypotension and bronchiolar constriction.
187
Autoimmune Disease
an inappropriate immune attack triggered by the body’s own proteins acting as antigens
The immune attack, mediated by autoantibodies and self-reactive T cells, is directed against the body cells that contain these proteins
188
Autoimmune Disease Examples
* Type 1 diabetes mellitus
* Rheumatoid arthritis
* Multiple sclerosis
* Myasthenia gravis
189
Autoimmune Disease Examples
* Type 1 diabetes mellitus
* Rheumatoid arthritis
* Multiple sclerosis
* Myasthenia gravis
