1
Q
What are alloantigens?
A
- Cell surface markers
- Determine blood group
- Responsible for incompatibilities in blood transfusion or organ grafting
Alloantigens occur in some members of the same species but not in others.
2
Q
What are superantigens known for?
A
- Potent T cell stimulators
- Cause toxic shock toxin leading to massive release of cytokines
This can result in cell death.
3
Q
Define allergens.
A
Antigens that evoke allergic reactions
Allergens can trigger immune responses that lead to allergy symptoms.
4
Q
What are autoantigens?
A
Self molecules mistakenly targeted by the immune system
Arise from immune tolerance failure.
5
Q
What is the role of the adaptive immunity system?
A
A coordinated system involving complex defense networks
It includes development, differentiation, and responses of the immune system.
6
Q
What are the two types of responses in the dual lymphocyte system?
A
- Humoral Response
- Cell-Mediated Response
B-cells and T-cells are involved in these responses.
7
Q
B-Cells are stimulated by an A____________ to produce specific A____________.
A
antigen, antibodies
This process is crucial for the humoral immune response.
8
Q
T-Cells are stimulated by an A___________ i_______ in a host cell or in a cell m____________.
A
antigenic, membrane
This is essential for the cell-mediated immune response.
9
Q
Where do B and T cells develop and migrate to?
A
- Lymph nodes
- Spleen
- Gut-associated lymphatic tissue (GALT)
Also includes skin-associated lymphatic tissue (SALT) and mucosa-associated lymphatic tissue (MALT).
10
Q
What do B-Cells defend against?
A
- Bacteria
- Parasites
- Fungi
B-cells are primarily responsible for humoral immunity.
11
Q
What do T-Cells defend against?
A
- Viruses
- Cancer cells
T-cells are crucial for cell-mediated immunity.
12
Q
What is the Major Histocompatibility Complex (MHC)?
A
Set of cell surface proteins essential for the acquired immune system
MHC molecules help in the recognition of self and rejection of foreign molecules.
13
Q
What are the two main groups of MHC genes?
A
- MHC Class I genes
- MHC Class II genes
These groups have distinct functions in immune response.
14
Q
What is the main function of Class I MHC?
A
Interacts with CD8+ Cytotoxic T cells
It displays self and infected cell peptides.
15
Q
What is the main function of Class II MHC?
A
Presents foreign antigens to CD4+ Helper T cells
This activates adaptive immune responses.
16
Q
How do lymphocytes recognize billions of antigens?
A
Using special receptors located on their surfaces
B-cells bind free antigens, while T-cells bind processed antigen fragments displayed on MHC molecules.
17
Q
What are the three lines of defense in the immune system?
A
- 1st line: Physical and chemical barriers
- 2nd line: Nonspecific responses (phagocytic cells, inflammation)
- 3rd line: Specific responses (B & T lymphocytes, antibodies)
This hierarchy helps protect the body from pathogens.
18
Q
What is clonal deletion?
A
Elimination of harmful lymphocyte clones that recognize self
This process ensures self-tolerance and immune system reliability.
19
Q
What are mature, naïve lymphocytes?
A
Lymphocytes that are self-tolerant, functional, and unique
They have not yet encountered their specific antigen.
20
Q
What happens during clonal selection?
A
An antigen binds to the lymphocyte clone whose receptor matches it
This triggers a specific immune response.
21
Q
What is the outcome of clonal expansion?
A
- Production of many identical cells (clones)
- Differentiation into effector and memory cells
This process enhances the immune response to the specific antigen.
22
Q
What is Adaptive Immunity?
A
A specific and powerful immune response
Provides long-term protection through infection (e.g., measles) and vaccination.
23
Q
Key players in Adaptive Immunity include:
A
- B Lymphocytes
- T Lymphocytes
Each is programmed to recognize one unique antigen.
24
Q
The selective ability of lymphocytes to recognize unique antigens is called immunocompetence.
A
True
This ability begins in utero and continues into late puberty.
25
What are the **three cell types** that can serve as antigen-presenting cells (APCs)?
* Macrophages
* Dendritic cells
* B cells
## Footnote
APCs modify the antigen and present it to T cells.
26
Antigens must be processed by _______ before their contact with T cells.
antigen-presenting cells (APC)
## Footnote
This processing is crucial for T-cell activation.
27
The **activation** of T-cells involves which components?
* APCs
* Helper T-cells
* Antigen-specific T-cells
## Footnote
This process is essential for T-cell mediated immunity.
28
Main classes of **T cells** include:
* T helper cells (CD4)
* Cytotoxic T cells (CD8)
* Regulatory T cells (CD4/CD25)
* Memory T cells
* Natural Killer (NK) cells
## Footnote
Each type has distinct roles in the immune response.
29
What do **Cytotoxic T cells (CD8)** do?
Destroy foreign or abnormal cells
## Footnote
They secrete perforins and granzymes to lyse cells.
30
What is the role of **Natural Killer (NK) cells**?
First responders to virus-infected and cancerous cells
## Footnote
They use perforins and granzymes to induce apoptosis.
31
What makes **Adaptive Immunity** unique?
* Specificity
* Memory
## Footnote
Each response is tailored to a unique antigen and lymphocytes recall prior exposure.
32
The **B-Cell Receptor** is composed of:
* 2 identical heavy chains
* 2 identical light chains
## Footnote
This structure allows for specific antigen binding.
33
What is the process of **B-Cell Activation**?
* Clonal Selection
* Antigen Binding
* Antigen Processing and Presentation
* B-Cell/T-Cell Cooperation
## Footnote
These steps lead to the production of antibodies.
34
Antigens are substances that elicit an **immune response** in specific lymphocytes.
True
## Footnote
Antigenicity is the property of behaving as an antigen.
35
What are the components of **Antibody Structure**?
* 4 polypeptide chains
* 2 heavy chains
* 2 light chains
## Footnote
Antibodies are immunoglobulins that play a crucial role in the immune response.
36
What is the function of the **Fab fragment** of an antibody?
Binds a specific epitope
## Footnote
It contains variable regions for flexibility and binding.
37
What is the role of the **Fc fragment** of an antibody?
Interacts with immune system cells and molecules
## Footnote
It does not bind antigens directly.
38
What are the **two major functional fragments** of antibodies?
* Fab (antigen-binding fragment)
* Fc (crystallizable fragment)
## Footnote
Fab binds specific epitopes and contains a hinge for flexibility, while Fc interacts with immune system cells and does not bind antigens directly.
39
The **Fab** fragment of an antibody binds to a specific _______ via variable regions.
epitope
## Footnote
This binding is crucial for the antibody's ability to recognize and neutralize antigens.
40
What is the **classic model** for antibody structure?
IgG
## Footnote
IgG serves as a standard reference for understanding antibody structure and function.
41
Antibodies are released by _______ B-cells.
plasma
## Footnote
Plasma B-cells are responsible for producing antibodies in response to antigens.
42
Antibodies bind specifically to an _______ on an antigen.
epitope
## Footnote
This interaction is essential for the immune response.
43
Antibodies consist of **4 polypeptide chains** held together by _______ bonds.
disulfide
## Footnote
These bonds provide structural integrity to the antibody.
44
What are the **five functional classes** (isotopes) of immunoglobulins (Ig)?
* IgG
* IgA
* IgM
* IgD
* IgE
## Footnote
Each class has distinct roles in the immune response.
45
IgG is produced by _______ cells during the primary response and memory cells during the secondary response.
plasma
## Footnote
IgG is the most prevalent antibody in the serum.
46
IgA circulates as a **monomer** in blood and as a _______ in mucous and serous secretions.
dimer
## Footnote
IgA plays a crucial role in mucosal immunity.
47
IgM is a _______ that is the first class synthesized following antigen encounter.
pentamer
## Footnote
IgM has 10 binding sites, making it effective in agglutinating pathogens.
48
IgD serves as a receptor for _______ on B cells.
antigen
## Footnote
This function is important for B cell activation.
49
IgE is involved in _______ responses and parasitic worm infections.
allergic
## Footnote
IgE binds to mast cells and basophils, triggering allergic reactions.
50
IgGs make up approximately ___% of serum antibodies.
75
## Footnote
They are the only antibodies that can cross the placenta.
51
IgMs make up approximately ___% of serum antibodies and are limited to _______ vessels.
10
* blood
## Footnote
IgMs are too large to enter tissues.
52
IgAs make up approximately ___% of serum antibodies and are found in _______ mucous membranes.
15
* body
## Footnote
They protect mucosal surfaces from pathogens.
53
IgDs make up approximately ___% of serum antibodies and function to stimulate _______ cell activation.
1
* B
## Footnote
They are primarily found on the surface of B cells.
54
IgEs make up approximately _______% of serum antibodies and are larger than IgGs.
0.1
## Footnote
They are involved in allergic reactions and defense against parasites.
55
The **primary immune response** is characterized by a latent period with no measurable antibody, followed by the appearance of _______.
IgM
## Footnote
IgM is the first antibody produced in response to an antigen.
56
In the **secondary immune response**, a rapid rise in antibody titer, mainly of _______, occurs.
IgG
## Footnote
This response is quicker due to the presence of memory lymphocytes.
57
What is the **titer** in the context of humoral immunity?
the amount of antibodies present
## Footnote
Titer is a measure of the immune response to an antigen.
58
Antibodies are detected by their ________.
* agglutination
* opsonization
* neutralization
* complement fixation/lysis
## Footnote
These reactions are essential for pathogen elimination.
59
What are the **functions of antibodies** in Ag-Ab reactions?
* Precipitation
* Agglutination
* Opsonization
* Neutralization
* Complement fixation & lysis
## Footnote
These functions help protect the body from pathogens.
60
Monoclonal antibodies (MABs) are produced from a single _______ cell clone.
B
## Footnote
MABs provide high specificity and purity for diagnostic and therapeutic applications.
61
Antigens are recognized by the immune system as 'non-self' due to their large, complex _______.
proteins
## Footnote
Antigens can also be lipoproteins, glycoproteins, or polysaccharides.
62
Haptens are molecules that are too _______ to elicit an immune response.
small
## Footnote
Haptens require a carrier to trigger an immune response.
63
What is **artificial passive immunization** useful for?
* Immunocompromised patients
* Immediate protection lasting 2 to 3 months
* Treatment of choice for preventing measles and hepatitis A
* Replacing antibodies in immunodeficient patients
## Footnote
It involves the use of human antisera and intravenous immune globulin (IVIG).
64
What are the components of **artificial passive immunization**?
* Human antisera
* Intravenous immune globulin (IVIG)
* Specific immune globulin (SIG) from hyperimmune donors
## Footnote
SIG is derived from donors vaccinated or infected by specific pathogens.
65
What are **antisera and antitoxins** of animal origin used for?
* Diphtheria
* Botulism
* Spider and snake bites
## Footnote
Sera produced in horses are commonly used for these treatments.
66
Define **artificial active immunity**.
Conferred artificially by vaccination, stimulating a primary and secondary anamnestic response
## Footnote
It prepares the immune system for future exposure to a virulent pathogen.
67
A vaccine is an **a___________** stimulus producing **l_____** lasting, protective immunity but not **d_________**.
antigenic, long, disease
## Footnote
Vaccines are designed to elicit an immune response without causing the disease.
68
Most vaccines are prepared from what types of materials?
* Killed whole cells or inactivated viruses
* Live, attenuated cells or viruses
* Antigenic molecules from bacterial cells or viruses
* Genetically engineered microbes or microbial agents
## Footnote
These preparations are essential for effective immunization.
69
What are the **types of vaccines** mentioned?
* Attenuated Microbe
* Inactivated Microbe
* Toxoid
* Subunit: Polysaccharide, Conjugate Vaccine
* Subunit: Recombinant Vaccine
* Immunotherapy
* DNA & RNA Vaccines
## Footnote
These categories reflect the various approaches to vaccine development.
70
What characterizes **live, attenuated vaccines**?
* Live weakened microbes
* Cells colonize and multiply but do not cause disease
* Evokes a strong, long-lasting immune response
## Footnote
Examples include MMR, TB (BCG), and Chicken Pox (Varicella).
71
What are the **advantages** of live-attenuated vaccines?
* Mimics natural infection
* Long-lasting immunity
* Fewer boosters needed
## Footnote
However, they require cold storage and have risks of reversion to virulence.
72
What are **killed (inactivated) vaccines**?
* Microbes killed by heat, radiation, or formalin
* Antigenic structure remains intact
## Footnote
Examples include IPV polio, cholera, and inactivated influenza.
73
What are **subunit and acellular vaccines**?
* Use purified antigenic parts of microbes
* Acellular from bacteria (e.g., cell wall)
* Subunit from viruses (e.g., surface proteins)
## Footnote
Examples include pneumococcal and meningococcal capsules.
74
What do **toxoid vaccines** contain?
* Inactivated bacterial exotoxins
* Stimulate antitoxin production
## Footnote
Protect against toxin-based diseases like tetanus and diphtheria.
75
What is the significance of **recombinant subunit vaccines**?
* Gene of the pathogen placed inside another organism
* Produces large quantities of pathogen antigens
## Footnote
Examples include Hepatitis B and HPV vaccines.
76
What is the **importance of vaccination**?
* Preventable infectious diseases cause 2 to 3 million child deaths annually
* Prevention is more effective, easier, and cheaper than treatment
## Footnote
Vaccines are not available for all diseases, such as HIV and malaria.
77
What are the **advantages of DNA/RNA vaccines**?
* Easy and inexpensive to make
* Producing strong, long-term immunity
## Footnote
They utilize genetic material to trigger an immune response without causing infection.
78
What do **mRNA vaccines** do?
* Inoculate viral RNA into the recipient
* Cause B and T cells to be sensitized
## Footnote
They are a primary means of protecting against COVID-19.
79
What type of **RNA** is inoculated into the recipient for protection against COVID-19?
mRNA
## Footnote
mRNA vaccines like Pfizer and Moderna use messenger RNA to instruct cells to produce a viral protein.
80
What is the **primary means** of protecting against COVID-19?
Vaccine
## Footnote
Vaccines stimulate the immune response to protect against the virus.
81
What does inoculation cause in the immune system?
* B cells to be sensitized
* T cells to be sensitized
* Formation of memory cells
## Footnote
This process helps the body recognize and fight the virus in the future.
82
The mRNA from the vaccine is eventually destroyed by _______ in the cell.
enzymes
## Footnote
This ensures that there is no permanent trace of the mRNA in the body.
83
What are the two **RNA vaccines** mentioned for COVID-19?
* Pfizer
* Moderna
## Footnote
Both vaccines utilize mRNA technology to elicit an immune response.
84
The mRNA for the spike protein is packaged into a **Lipid Nano Particle (LNP)**. Why is the LNP coating important?
Lipids do not get degraded and can fuse with cell membranes
## Footnote
This allows for effective delivery of mRNA into cells.
85
What is the **ideal vaccine** characterized by?
* Mimics the real disease
* Non-toxic
* No side effects
* 100% effectiveness in every patient
* Evokes a powerful immune response
* User-friendly and easy storage
* Long shelf-life
* Cheap
## Footnote
These characteristics ensure widespread accessibility and effectiveness.
86
What is the **recommended immunization schedule** for children and adolescents?
https://www.cdc.gov/vaccines/schedules/downloads/child/0-18yrs-child-combined-schedule.pdf
## Footnote
This schedule outlines vaccinations for individuals 18 years or younger.
87
Vaccines hold great promise for the future, including **genetically modified microbes** and novel technology vaccines. What do we want from these advancements?
* Millions of lives saved
* Less misery
* Accessibility to all
## Footnote
These goals aim to improve public health outcomes globally.
88
True or false: **Disease prevention** is always better than control.
TRUE
## Footnote
Preventing disease is more effective than managing it after it occurs.
89
What does **Herd Immunity** require?
A sufficient number of resistant individuals
## Footnote
This prevents infection of susceptible members and limits disease spread.
90
What is the **R0 value**?
The average number of healthy people that one sick person may infect
## Footnote
It helps determine the threshold percentage needed for herd immunity.
91
List the **types of immunity**.
* Active Immunity
* Passive Immunity
* Naturally Acquired Immunity
* Artificially Acquired Immunity
## Footnote
Each type has different mechanisms of action and duration.
92
What is **Active Immunity**?
Results when a person is challenged with an antigen that stimulates antibody production
## Footnote
It creates memory and is long-lasting.
93
What is **Passive Immunity**?
Preformed antibodies are donated to an individual
## Footnote
It acts immediately but does not create memory and is short-term.
94
What is **Natural Passive Immunity**?
Mother to child transfer of antibodies
## Footnote
IgG antibodies pass through the placenta, and IgA antibodies are present in breast milk.
95
What is **Artificial Active Immunization**?
Vaccination
## Footnote
It triggers the immune system to produce antibodies and memory cells.
96
What is the **adaptive immunity** also known as?
Acquired immunity
## Footnote
It is sometimes referred to as the third line of defense.
97
Define **immunocompetence**.
The ability of the body to interact with a wide spectrum of foreign substances
## Footnote
This ability begins to develop during fetal development.
98
What are the two main types of specialized leukocytes involved in acquired adaptive immunity?
* B lymphocytes
* T lymphocytes
## Footnote
These cells undergo a selective process to react to specific antigens.
99
What are **antigens**?
Molecules that can stimulate a response by T and B cells
## Footnote
They can consist of proteins, polysaccharides, and other compounds.
100
List two characteristics shared by **PAMPs** and antigens.
* Parts of foreign cells (microbes)
* Provokes a reaction by the white blood cells of the host
## Footnote
PAMPs stimulate nonspecific responses, while antigens stimulate specific immune responses.
101
True or false: **Adaptive immunity** is selective and has memory.
TRUE
## Footnote
It is different from innate immunity, which is nonspecific.
102
What are the **four sections** detailing the specific immune responses?
* Development and differentiation of the immune system
* Lymphocyte maturation and the nature of antigens
* Immune reactions to antigens and the activities of T cells
* Immune activities of B Cells and the production and actions of antibodies
## Footnote
These sections help organize the complex immune response system.
103
What is the role of **cell surface receptors** in the immune system?
Confer specificity and identity
## Footnote
They are responsible for specific immune recognition and reactions.
104
Fill in the blank: The **adaptive immunity** is responsible for long-term protection developed through infections or _______.
vaccinations
## Footnote
This system is crucial for resisting infectious agents.
105
What is the **theoretical potential** of an infant regarding immune response?
To produce an immune response to hundreds of millions of different foreign molecules or antigens
## Footnote
Completion of immunocompetence takes many years.
106
What are the **major functions** of immune receptors?
* Perceive and attach to nonself or foreign antigens
* Promote the recognition of self antigens
* Receive and transmit chemical messages among other cells
* Aid in cellular development
## Footnote
Immune receptors play a crucial role in detection, recognition, and cell communication.
107
What does **MHC** stand for?
Major Histocompatibility Complex
## Footnote
The MHC is also known as the human leukocyte antigen (HLA) system.
108
Class I MHC genes code for markers that display unique characteristics of **self** and allow for the recognition of _______.
self molecules
## Footnote
Class I MHC is essential for the regulation of immune reactions.
109
What are the **two classes** of MHC molecules?
* Class I MHC
* Class II MHC
## Footnote
Class I MHC is found on all human cells except red blood cells, while Class II MHC is found on antigen-presenting cells.
110
What types of cells express **Class II MHC**?
* Macrophages
* Dendritic cells
* B cells
## Footnote
These cells are known as professional antigen-presenting cells (APCs).
111
B-cell receptors bind _______ antigens, while T-cell receptors bind processed antigens together with _______.
free; MHC molecules
## Footnote
This specificity is crucial for immune surveillance and recognition.
112
The **Clonal Selection Theory** explains how lymphocytes generate diversity in their receptors. True or False?
TRUE
## Footnote
This theory describes how undifferentiated lymphocytes undergo divisions and genetic changes to create a vast repertoire of specific receptors.
113
How many genes do lymphocytes use to produce their repertoire of specific receptors?
Slightly more than 500
## Footnote
This genetic information allows lymphocytes to respond to a vast number of different antigens.
114
Where do T cells migrate to after development in the bone marrow?
Thymus
## Footnote
B cells remain in the bone marrow, while T cells 'home' to the thymus for further maturation.
115
By the time T and B cells reach the lymphoid tissues, each one is already equipped to respond to a _______ antigen.
single unique
## Footnote
This specificity is established during their development in primary lymphoid tissues.
116
What are the **two main types** of lymphocytes involved in the immune response?
* B cells
* T cells
## Footnote
These cells play crucial roles in the adaptive immune system.
117
Where do **B cells** and **T cells** undergo differentiation and maturation?
* B cells: Bone marrow
* T cells: Thymus
## Footnote
Each type of lymphocyte develops in a specific organ.
118
What is the term for a genetically unique line of lymphocytes arising from extensive genetic recombinations?
clone
## Footnote
Clones are essential for the diversity of the immune response.
119
The presence of **forbidden clones** in lymphocyte development can lead to what potential issue?
Autoimmunity
## Footnote
Forbidden clones can react against self MHC antigens, causing damage.
120
What is the process called that eliminates potentially harmful clones during lymphocyte development?
clonal deletion
## Footnote
This process is part of establishing immune tolerance.
121
What is the second stage of lymphocyte development that requires stimulation by antigens?
clonal selection and expansion
## Footnote
This stage increases the population of lymphocytes specific to an antigen.
122
True or false: Lymphocyte specificity is preprogrammed and exists before an antigen enters the tissues.
TRUE
## Footnote
Each genetically distinct lymphocyte can react to only one type of antigen.
123
What type of molecule serves as the specific receptors of **B cells** and as antibodies?
Immunoglobulin (Ig)
## Footnote
Immunoglobulins are large glycoprotein molecules.
124
What is the basic structure of an **immunoglobulin** molecule?
* Two heavy (H) chains
* Two light (L) chains
## Footnote
The structure forms a symmetrical, Y-shaped arrangement.
125
What are the **antigen binding sites** on immunoglobulins characterized by?
High variability in shape
## Footnote
This variability allows binding to a wide range of antigens.
126
How many different genes code for the variable region of light chains in an undifferentiated lymphocyte?
About 150 genes
## Footnote
These genes undergo recombination during B-cell development.
127
What is the role of the **constant (C) regions** in immunoglobulins?
Maintain structural integrity
## Footnote
The constant regions do not vary greatly among different antibodies.
128
What is the process of selecting active gene segments during B lymphocyte maturation compared to?
Molecular 'cut and paste'
## Footnote
This process ensures specificity in mature lymphocytes.
129
What is the process of **gene splicing** in lymphocytes?
Cuts out particular blocks of DNA and splices them together
## Footnote
This process leaves only selected segments that code for a specific polypeptide receptor.
130
What happens to **unused gene segments** in lymphocytes?
Permanently removed from the genome
## Footnote
Only selected segments remain, coding for specific polypeptide receptors.
131
For a **heavy chain**, which gene segments are selected and spliced together?
* One variable region gene segment
* One diversity region gene segment
* One joining region gene
* One constant region gene
## Footnote
This selection is from hundreds of available segments.
132
For a **light chain**, which gene segments are spliced together?
* One variable gene segment
* One joining gene segment
* One constant gene segment
## Footnote
This combination is essential for forming the light chain of an immunoglobulin.
133
What is formed when a **heavy chain** combines with a **light chain**?
Half an immunoglobulin
## Footnote
Two halves combine to form a completed protein.
134
What happens to the **immunoglobulin product** after synthesis?
Transported to the cell membrane and inserted there
## Footnote
Acts as a receptor that expresses the specificity of that cell.
135
What is notable about the genes selected for the **variable region** of a lymphocyte?
Locked in for the rest of the life of that lymphocyte and its progeny
## Footnote
This ensures the specificity of the lymphocyte is maintained.
136
What can be altered in the **constant region** of an immunoglobulin?
Provides different functional properties
## Footnote
This allows for variation in the function of the immunoglobulin.
137
The **T-cell receptor for antigen** belongs to the same protein family as what?
B-cell receptor
## Footnote
Both are formed by genetic modification and have variable and constant regions.
138
How does the **T-cell receptor** differ from the **B-cell receptor**?
Relatively small and not secreted
## Footnote
It is equivalent to one fork of the B-cell receptor.
139
What is formed from the **two parallel polypeptide chains** in T-cell receptors?
Antigen binding site
## Footnote
This site is crucial for the T-cell's interaction with antigens.
140
What are **clusters of differentiation** or CD receptors involved in during T-cell maturation?
* Cell receptors
* Cell adhesion
* Communication
## Footnote
CD molecules are denoted with a number, such as CD1, CD2, etc.
141
Which two **CD groups** are primarily focused on in T cells?
* CD4 receptors (T helper cells)
* CD8 receptors (T cytotoxic cells)
## Footnote
These receptors interact with MHC markers during immune reactions.
142
True or false: **Mature T cells** do not migrate to specific sites in lymphoid organs.
FALSE
## Footnote
Mature T cells migrate to specific sites in lymphoid organs and circulate from there.
143
Approximately how many **T cells** pass between the lymphatic and general circulation per day?
25 x 10^6 T cells
## Footnote
This high number indicates the dynamic nature of T cell circulation.
144
What are the **specific sites** of B-cell maturation?
Certain **bone marrow regions** that harbor stromal cells
## Footnote
Stromal cells nurture lymphocyte stem cells and provide chemical signals for B-cell development.
145
What do naive B lymphocytes travel to after maturation?
* Lymph nodes
* Spleen
* Mucosal-associated lymphoid tissue (MALT)
## Footnote
They adhere to specific binding molecules and come into contact with antigens throughout life.
146
What do B cells display as surface receptors for antigens?
**Immunoglobulins**
## Footnote
Immunoglobulins are crucial for the recognition of antigens.
147
Define **antigen**.
Any molecule or fragment of a molecule that has the potential to trigger a specific immune response by lymphocytes
## Footnote
This property is known as **antigenicity**.
148
What is an **immunogen**?
A type of antigen that induces a specific immune response when introduced into the body
## Footnote
Immunogens meet all conditions to stimulate an immune reaction.
149
True or false: All antigens are immunogenic.
FALSE
## Footnote
Some antigens may not trigger an immune response, while immunogens do.
150
What is an example of an antigen that is **antigenic but not immunogenic**?
Small polysaccharides from the capsule of **Haemophilus influenzae**
## Footnote
These molecules are foreign but too small to trigger a lymphocyte response.
151
What is a key characteristic of an antigen?
Immune cells react to it as **nonself** or foreign
## Footnote
This means it is not a normal constituent of the body.
152
List the **chemical categories** that most materials serving as antigens fall into.
* Proteins and large polypeptides (enzymes, cell surface receptors, hormones, exotoxins)
* Molecules that contain two or more different macromolecules (e.g., lipoproteins, lipopolysaccharides)
## Footnote
These substances often originate from the cell membranes or cell walls of microbes.
153
What does the term **antigen** literally mean?
An **antibody generator**
## Footnote
This highlights the role of antigens in stimulating an immune response.
154
155
156
157
What is the **molecular weight (MW)** threshold for a substance to be considered a complete antigen?
At least 100,000 MW
## Footnote
Molecules with a MW of less than 1,000 are seldom complete antigens, while those between 1,000 MW and 10,000 MW are weakly antigenic.
158
Define **epitope**.
Antigenic determinant that provides the primary signal that the molecule is foreign
## Footnote
The lymphocyte recognizes and responds to the epitope.
159
What are examples of **complex macromolecules** that are most immunogenic?
* Large proteins
* Certain polysaccharides (bacterial capsules)
* Glycolipids (mycolic acid of M. tuberculosis)
## Footnote
Complex macromolecules of at least 100,000 MW are the most immunogenic.
160
True or false: **Large size alone** is sufficient for antigenicity.
FALSE
## Footnote
Large size must be accompanied by appropriate molecular structure to elicit an immune response.
161
What are **haptens**?
Small foreign molecules that are too small to elicit an immune response by themselves
## Footnote
Haptens can develop immunogenicity when linked to a larger carrier molecule.
162
What are **alloantigens**?
Cell surface markers and molecules that occur in some members of the same species but not in others
## Footnote
Alloantigens are responsible for blood group and major histocompatibility profile incompatibilities.
163
Name two examples of **superantigens**.
* Toxic shock toxin
* Enterotoxin of Staphylococcus
## Footnote
Superantigens are potent stimuli for T cells and can cause massive cytokine release.
164
What are **allergens**?
Antigens that evoke allergic reactions
## Footnote
Allergens will be characterized in detail in chapter 16.
165
During lymphocyte differentiation, what occurs to prevent immune response against **self tissue**?
Immune tolerance
## Footnote
Some anatomical sites can contain sequestered molecules that escape immune tolerance.
166
What are **autoantigens** and where can they occur?
* Tissues of the eye
* Thyroid gland
## Footnote
Autoantigens can be mistaken as foreign due to lack of tolerance established early in embryonic development.
167
What types of diseases can the mechanism of autoantigens account for?
* Autoimmune diseases
* Rheumatoid arthritis
## Footnote
This mechanism involves the immune system mistakenly targeting the body's own tissues.
168
What is the basis for most **immune responses**?
The encounter between **antigens** and **white blood cells**
## Footnote
Microbes and foreign substances typically enter through mucosal surfaces.
169
Where do antigens introduced intravenously become localized?
* Liver
* Spleen
* Bone marrow
* Kidney
* Lung
## Footnote
Different routes of antigen introduction affect their localization in the body.
170
What are the three different cells that can serve as **antigen-presenting cells (APCs)**?
* Macrophages
* Dendritic cells
* B cells
## Footnote
Dendritic cells are the most common APC in first contact with an antigen.
171
What must happen to an antigen before it is ready for contact with **T cells**?
It must be further acted upon by **antigen-presenting cells (APCs)**
## Footnote
APCs modify the antigen to make it more immunogenic and recognizable.
172
What receptor do APCs bind the processed antigen to for T cell presentation?
**MHC class II receptor**
## Footnote
This binding makes the antigen readily accessible to T cells.
173
What type of antigens usually require recognition steps between the APC, antigen, and lymphocytes?
**T-cell-dependent antigens**
## Footnote
These are typically protein-based antigens.
174
What is the role of **T helper cells (TH)** in activating B cells and other T cells?
They assist in the recognition and activation process
## Footnote
TH cells bind to both the MHC receptor on the APC and the antigen.
175
What cytokine is produced by the APC to activate T helper cells?
**Interleukin-1 (IL-1)**
## Footnote
This cytokine is crucial for the activation of T helper cells.
176
What does the T helper cell produce to stimulate B and T cells?
**Interleukin-2 (IL-2)**
## Footnote
IL-2 stimulates a general increase in activity of committed B and T cells.
177
What are **T-cell-independent antigens**?
Antigens that can trigger a response from B lymphocytes without the cooperation of APCs or T helper cells
## Footnote
Usually simple molecules like carbohydrates with many repeating and invariable determinant groups.
178
Name examples of **T-cell-independent antigens**.
* Lipopolysaccharide from Escherichia coli
* Polysaccharide from Streptococcus pneumoniae
* Molecules from rabies and Epstein-Barr virus
## Footnote
These antigens are rare, and most B-cell reactions require assistance from T helper cells.
179
What does **CMI** stand for?
Cell-Mediated Immunity
## Footnote
Refers to the responses of T cells, which are complex and diverse in the immune system.
180
What is required for T cells to be activated?
Antigen offered by an **MHC complex** on an APC
## Footnote
This ensures recognition of self before T cells can react.
181
How do T cells differ from B cells in their function?
T cells react directly in contact with target cells, while B cells secrete molecules into circulation
## Footnote
T cells also stimulate other T cells, B cells, and phagocytes.
182
What happens when a T cell is initially sensitized?
The binding of antigen/MHC to its receptors activates the T cell
## Footnote
This leads to mitotic divisions and the formation of effector and memory cells.
183
What are **memory T cells**?
Long-lived blood cells that can interact with the antigen upon subsequent contact
## Footnote
They can live for decades, unlike other lymphocytes that last weeks or months.
184
What are the **two types of T cells** based on their receptors?
* CD4 T cells
* CD8 T cells
## Footnote
CD4 T cells recognize peptides presented on MHC II, while CD8 T cells recognize peptides presented on MHC I.
185
What is the role of **T Helper (TH) cells** in the immune response?
* Regulating immune reactions
* Activating macrophages
* Stimulating B cells
## Footnote
TH cells release cytokines like interleukin-2, -4, -5, and -6 to stimulate immune responses.
186
T helper cells make up about **what percentage** of the T cell population in blood and lymphoid organs?
65%
## Footnote
This prevalence highlights their central role in the immune system.
187
When activated by antigen/MHC II, T helper cells can differentiate into **which two types**?
* T helper 1 (TH1) cells
* T helper 2 (TH2) cells
## Footnote
The differentiation depends on the cytokines secreted by antigen-presenting cells.
188
What cytokines lead to the differentiation of T helper cells into **TH1 cells**?
* IL-1
* IL-12
## Footnote
TH1 cells are involved in activating more T cells and delayed hypersensitivity.
189
What cytokines lead to the differentiation of T helper cells into **TH2 cells**?
* IL-4
* IL-5
* IL-6
## Footnote
TH2 cells influence B-cell differentiation and antibody responses.
190
What are **cytotoxic T (Tc) cells** also known as?
Killer T cells
## Footnote
They are activated by antigen/MHC I and have the capacity to kill specific target cells.
191
What is the process by which cytotoxic T cells induce target cell death?
Apoptosis
## Footnote
This genetically programmed process results in the destruction of the nucleus and complete cell lysis.
192
What types of cells can be destroyed by **Tc cells**?
* Virally infected cells
* Cancer cells
* Cells from other animals and humans
## Footnote
Tc cells play a crucial role in immune defense against these cell types.
193
What are **natural killer (NK) cells**?
A type of lymphocyte related to T cells
## Footnote
NK cells are part of cytotoxic cell-mediated immunity and attack cancer and virus-infected cells.
194
What cytokines moderate the activities of **NK cells**?
* Interleukin-12
* Interferon
## Footnote
These cytokines help regulate the immune response of NK cells.
195
What are **superantigens** primarily associated with?
Bacteria and viruses
## Footnote
Superantigens are a form of virulence factor that can provoke overwhelming immune responses.
196
Name an example of a **superantigen**.
* Enterotoxin from pathogenic staphylococci
* Toxins of group A streptococci
* Proteins of Epstein-Barr virus
## Footnote
These examples illustrate how superantigens can trigger significant immune responses.
197
Superantigens can provoke overwhelming immune responses by large numbers of **T cells** regardless of __________.
specificity
## Footnote
This characteristic allows superantigens to activate T cells in a non-specific manner.
198
How do **superantigen molecules** interact with T cells?
They span both MHC-II receptors and antigen receptors (TCR)
## Footnote
This interaction tricks T cells into releasing massive amounts of cytokines.
199
What cytokines are released in large amounts due to superantigen activation?
* Tumor necrosis factor
* Interleukins-1
* Interleukins-6
## Footnote
The release of these cytokines can lead to severe physiological consequences.
200
What serious conditions can result from the overwhelming influx of cytokines due to superantigens?
* Blood vessel damage
* Toxic shock
* Multiorgan failure
## Footnote
These conditions are thought to be mechanisms underlying toxic shock syndrome and other serious infections.
201
What is the first step in the **activation of B lymphocytes**?
Clonal selection and binding of antigen
## Footnote
A pre-committed B cell picks up the antigen on its Ig receptors and processes it into small peptide determinants.
202
What do B cells require for **immunologic activation**?
A series of steps including:
* Clonal selection and binding of antigen
* Induction by chemical mediators
## Footnote
Developmental signals from macrophages and T cells are crucial for B cell activation.
203
What are the **chemical mediators** that induce B cell activation?
* Interleukin-2
* Interleukin-6
* IL-4
* IL-5
## Footnote
These growth factors are essential for B cell development and activation.
204
What is the role of **MHC-II receptors** in B cell activation?
They bind processed antigens for presentation to T helper cells
## Footnote
The MHC/Ag complex on the B cell is crucial for T cell recognition.
205
What is the process by which B cells recognize and bind to microbes?
B cells can independently recognize microbes and bind them with their **Ig receptors**
## Footnote
This is how the initial selection of the antigen-specific B-cell clone occurs.
206
What happens to the microbe once it is attached to the B cell?
The B cell endocytoses it, processes it, and displays it on the **MHC-II complex**
## Footnote
This prepares the antigen for presentation to a specific T helper cell.
207
What is **linked recognition** in B cell activation?
The MHC-II receptor on the B cell binds to the T-cell antigen receptor and the CD4 molecule on the T cell
## Footnote
This interaction is essential for B cell activation.
208
What signals does the T cell provide to activate the B cell?
Additional signals in the form of **interleukins** and B-cell growth factors
## Footnote
These signals lead to increased cell metabolism and activation of the B cell.
209
What is the outcome of **B cell activation**?
Increased cell metabolism, enlargement, proliferation, and differentiation
## Footnote
This leads to the production of memory cells and plasma cells.
210
What are the two types of cells produced during **clonal expansion**?
* Memory cells
* Plasma cells
## Footnote
Memory cells persist for long-term immunity, while plasma cells are short-lived and secrete antibodies.
211
What do **plasma cells** do?
Synthesize and release antibodies
## Footnote
These antibodies have the same specificity as the Ig receptor and circulate to react with antigens.
212
What type of antibodies do plasma cells primarily produce?
IgM antibodies
## Footnote
These antibodies circulate in the body and react with the same antigens recognized by the B cell.
213
What triggers **B-cell activation**?
The combination of stimuli on the membrane receptors
## Footnote
This causes a signal to be transmitted internally to the B-cell nucleus.
214
What is an **activated B cell** referred to as?
Lymphoblast
## Footnote
An activated B cell enlarges and increases its synthesis of DNA and protein in preparation for mitosis.
215
What is **clonal expansion** in B cells?
The stimulated B cell multiplies through successive mitotic divisions
## Footnote
This produces a large population of genetically identical daughter cells.
216
What are **memory cells**?
Cells that remain for long periods to react with the same antigen
## Footnote
They expand the clone size upon subsequent exposure to the antigen.
217
What are the large, specialized B cells called that are produced during clonal expansion?
Plasma cells
## Footnote
They are terminally differentiated B cells that secrete antibodies.
218
What is the primary action of **plasma cells**?
To secrete copious amounts of antibodies
## Footnote
These antibodies have the same specificity as the original receptor.
219
How many antibodies can an individual **plasma cell** produce per second?
Around 2,000 antibodies
## Footnote
However, production does not continue indefinitely, and plasma cells do not survive for long.
220
What does **Ig** stand for?
Immunoglobulins
## Footnote
They are proteins found in the globulin fraction of the serum and have immune function as antibodies.
221
What are the two functionally distinct segments of an **IgG molecule**?
* Antigen binding fragments (Fabs)
* Crystallizable fragment (Fc)
## Footnote
Fabs bind antigen, while Fc is involved in binding to various cells and molecules of the immune system.
222
What is the role of the **hinge region** in antibodies?
Allows swiveling of the Fabs
## Footnote
This enables them to change their angle to accommodate nearby antigen sites.
223
What is the **antigen binding site** composed of?
Hypervariable regions with an extremely variable amino acid content
## Footnote
This site has a specific three-dimensional fit for the antigen.
224
True or false: The specificity of **antigen binding sites** for antigens is similar to enzymes and substrates.
TRUE
## Footnote
Some antibodies have even been used as enzymes.
225
What is the principal activity of **secreted antibodies**?
To unite with, immobilize, call attention to, or neutralize the antigen
## Footnote
This is the action that initiated the immune response.
226
What is the **hypervariable region** of an antibody (Ab) responsible for?
Binding to antigen (Ag)
## Footnote
The hypervariable region determines the specificity of the antibody for its antigen.
227
What is **opsonization**?
Coating of microorganisms with specific antibodies
## Footnote
This process enhances recognition by phagocytes, making it easier for them to dispose of the coated particles.
228
How do antibodies **agglutinate** cells?
By cross-linking them into large clumps
## Footnote
This process renders microbes immobile and enhances their phagocytosis.
229
What is the difference between **agglutination** and **precipitation**?
Agglutination involves cells; precipitation involves small free antigen molecules
## Footnote
Both processes are important for certain immune tests.
230
What does **complement fixation** refer to?
The classical pathway of complement activation
## Footnote
This interaction can lead to the specific rupturing of cells and some viruses.
231
What is the role of antibodies in **neutralization reactions**?
Filling surface receptors on viruses or active sites on bacterial proteins
## Footnote
This prevents them from attaching to their target cells.
232
What are **antitoxins**?
Special types of antibodies that neutralize bacterial exotoxins
## Footnote
They play a crucial role in protecting against certain bacterial infections.
233
True or false: All antibodies are protective.
FALSE
## Footnote
Some antibodies neither benefit nor harm, and some can cause diseases, such as autoantibodies.
234
What is the **function of the Fc** fragment in immunoglobulins?
Binds to the membrane of cells such as macrophages, neutrophils, eosinophils, mast cells, basophils, and lymphocytes
## Footnote
The effect of Fc binding depends on the cell's role.
235
What is **opsonization**?
Attachment of antibody to foreign cells and viruses, exposing Fcs to phagocytes
## Footnote
This process enhances phagocytosis.
236
Certain antibodies have regions on the **Fc portion** for what purpose?
* Fixing complement
* Releasing cytokines
## Footnote
For example, IgE binds to basophils and mast cells, causing the release of histamine.
237
What are the two additional **accessory molecules** found on immunoglobulins?
* J chain
* Secretory component
## Footnote
J chain helps keep monomers of IgA and IgM together; secretory component helps move IgA across mucous membranes.
238
What are the **classes of immunoglobulins** known as?
Isotypes
## Footnote
Differentiated by variations in the Fc region.
239
What is the shorthand name for immunoglobulins?
Ig followed by a letter: IgG, IgA, IgM, IgD, IgE
## Footnote
The letters correspond to Greek letters gamma, alpha, mu, delta, and epsilon.
240
What is the structure of **IgG**?
Monomer
## Footnote
Produced by plasma cells late in a primary response and by memory cells upon re-exposure to an antigen.
241
What is the most prevalent antibody circulating throughout the blood, lymph, and extracellular fluids?
IgG
## Footnote
It has numerous functions including neutralizing toxins and opsonizing.
242
What unique ability does **IgG** have regarding the fetus?
Crosses the placenta
## Footnote
Provides protection to the fetus.
243
Define **monomer** in the context of immunoglobulins.
One unit
## Footnote
Dimer means two units, pentamer means five units, and polymer means many units.
244
What are the **two forms of IgA**?
* Monomer circulating in blood
* Dimer (secretory IgA) in mucous and serous secretions
## Footnote
The dimer is formed in a plasma cell by two monomers held together by a J chain.
245
What is the function of **secretory IgA**?
* Coats mucosal membranes
* Confers local immunity against pathogens
## Footnote
It appears in saliva, tears, colostrum, and mucus, protecting against enteric, respiratory, and genitourinary pathogens.
246
What is the structure of **IgM**?
* Pentamer composed of five monomers
* Attached by Fc portions to a central J chain
## Footnote
IgM has 10 binding sites and is the first antibody synthesized after the first encounter with an antigen.
247
What is the primary role of **IgD**?
* Serves as a receptor for antigen on B cells
## Footnote
It is usually found alongside IgM and triggers B-cell activation.
248
What is the biological significance of **IgE**?
* Stimulates inflammatory response
* Mediates anaphylaxis and allergies
## Footnote
IgE interacts with receptors on mast cells and basophils, enlisting blood cells to the site of infection.
249
What happens to antibodies after they are secreted?
* They end up in the blood through the body's networks
## Footnote
A sample of antiserum subjected to electrophoresis shows major protein groups migrating in a specific pattern.
250
What are the major groups of proteins identified in **electrophoresis** of antiserum?
* Albumins
* Alpha-1 globulins
* Alpha-2 globulins
* Beta globulins
* Gamma globulins
## Footnote
Most globulins represent antibodies, leading to the term immunoglobulin.
251
What does the term **titer** refer to?
The quantitative measure of antibody levels in serum over time
## Footnote
It helps in understanding the immune system's response to an antigen.
252
What is the **primary response** in the immune system?
The initial response to an antigen characterized by a latent period with no antibodies present
## Footnote
During this time, the antigen is concentrated in lymphoid tissue and processed by B lymphocytes.
253
What type of antibodies are primarily produced during the **early primary response**?
IgM
## Footnote
IgM is the first class of antibodies secreted by plasma cells.
254
What is the **secondary response** in the immune system?
The response that occurs upon re-exposure to the same antigen, characterized by increased antibody synthesis and faster response
## Footnote
This response is also known as the anamnestic response.
255
What are **memory B cells** responsible for?
Rapid and amplified antibody response during secondary exposure
## Footnote
They do not require as many signals to form plasma cells.
256
What is the significance of the **anamnestic response**?
It provides a quick and potent immune response against subsequent exposures
## Footnote
This is the basis for vaccine boosters.
257
What are **monoclonal antibodies (MABs)**?
Antibodies originating from a single clone with a single specificity for an antigen
## Footnote
They are essential for certain applications in immunology.
258
What is the difference between **active immunity** and **passive immunity**?
* Active immunity: Immune response from one's own lymphocytes
* Passive immunity: Received antibodies from another donor
## Footnote
Active immunity creates memory and can last a long time, while passive immunity provides immediate protection without memory.
259
What are the characteristics of **active immunity**?
* Essential attribute of an immunocompetent individual
* Creates memory for quick action upon re-exposure
* Requires several days to develop
* Can last for a long time, sometimes for life
## Footnote
Active immunity can be stimulated by natural or artificial means.
260
What are the characteristics of **passive immunity**?
* Lack of memory for the original antigen
* No production of new antibodies
* Immediate onset of protection
## Footnote
Passive immunity is provided by antibodies produced by another human or animal.
261
What is the **short-term effectiveness** of passive immunity?
Antibodies have a limited period of function and are disposed of by the recipient's body
## Footnote
Passive immunity can be natural or artificial in origin.
262
Define **natural immunity**.
Immunity acquired during normal biological experiences without medical intervention
## Footnote
It encompasses immunity gained through infections or other natural processes.
263
Define **artificial immunity**.
Protection from infection obtained through medical procedures
## Footnote
This type of immunity is induced by immunization with vaccines and immune serum.
264
What are the **four possible examples** of origins of immunity?
* Natural Active Immunity
* Natural Passive Immunity
* Artificial Active Immunization
* Artificial Passive Immunization
## Footnote
These categories encompass various ways immunity can be acquired.
265
What is **Natural Active Immunity**?
Getting an infection and recovering, leading to resistance against reinfection
## Footnote
Immunity duration varies; some infections provide nearly lifelong immunity.
266
What is **Natural Passive Immunity**?
Immunity acquired from mother to child during prenatal and postnatal periods
## Footnote
IgG antibodies cross the placenta and provide protection for the infant.
267
How do **IgG antibodies** provide immunity to infants?
They pass through the placenta during fetal life and protect the infant for the first few months
## Footnote
Antibodies against tetanus, diphtheria, and several viruses regularly cross the placenta.
268
What is the role of **mother's milk** in immunity?
Provides IgA antibodies that react against microbes entering the intestine
## Footnote
This protection is not available from transplacental antibodies.
269
Define **immunization**.
Any clinical process that produces immunity in a subject
## Footnote
It is also called immunoprophylaxis.
270
What is **Artificial Active Immunization**?
Vaccination, which exposes a person to a specially prepared antigen
## Footnote
The term vaccination originated from the Latin word vacea (cow).
271
What is the **definition** of **active immunity**?
The immune system produces antibodies and memory cells in response to a microbial (antigenic) stimulus
## Footnote
This protection varies in degree and length.
272
What is the **definition** of **passive immunity**?
A patient is administered a preparation containing specific antibodies against an infectious agent
## Footnote
This is a type of immunotherapy.
273
What are the **usual sources** of antibodies for passive immunization?
* Pooled human serum from donor blood (gamma globulin)
* Immune serum globulins containing high quantities of antibodies
## Footnote
These sources are used to protect against diseases like hepatitis A, rabies, and tetanus.
274
True or false: **Active immunization** is synonymous with vaccination.
TRUE
## Footnote
Active immunization involves administering some form of antigen.
275
True or false: **Passive immunization** triggers memory cell production.
FALSE
## Footnote
Passive immunization involves giving antibodies, not triggering memory.
276
Name at least **two major ways** in which **natural** and **artificial immunities** are different.
* Acquisition method
* Duration of immunity
## Footnote
These differences highlight the distinct processes involved in natural versus artificial immunity.
277
Explain why the **passive transfer of T-cell immunities** would be highly unlikely.
T-cell immunities are not transferred through antibodies
## Footnote
Passive immunity involves antibodies, not T-cells.
278
What is the first method of **passive immunization** mentioned?
Transfusion of horse serum containing antitoxins
## Footnote
This method was used to prevent tetanus and treat diphtheria exposure.
279
What does **immune serum globulin (ISG)** contain?
Immunoglobulin extracted from pooled blood of at least 1,000 human donors
## Footnote
ISG is used to prevent measles and hepatitis A and to replace antibodies in immunodeficient patients.
280
How long does the protection from **ISG** typically last?
2 to 3 months
## Footnote
Most forms of ISG are injected intramuscularly to minimize adverse reactions.
281
What is **specific immune globulin (SIG)** derived from?
Serum from patients in a hyperimmune state after vaccination or infection
## Footnote
SIG preparations are made from patients vaccinated or infected by pertussis, tetanus, chickenpox, and hepatitis B.
282
What is a key advantage of **SIG** over ISG?
Higher titers of specific antibodies from a smaller pool of patients
## Footnote
SIG is preferable for prophylaxis against infectious agents.
283
What are some examples of **antisera and antitoxins** of animal origin?
* Diphtheria
* Botulism
* Rabies
* Spider and snake bites
## Footnote
These sera can stimulate allergies such as serum sickness or anaphylaxis.
284
True or false: **Passive immunities** provide long-term protection.
FALSE
## Footnote
Passive immunities act immediately but only last a relatively short time.
285
What is the principle behind **active immunity** conferred by vaccination?
Stimulating a primary response to prime the immune system for future exposure
## Footnote
This leads to an immediate, powerful, and sustained secondary immune response.
286
What are the **four types of antigen preparations** used in vaccines?
* Killed whole cells or inactivated viruses
* Live, attenuated bacterial cells or viruses
* Antigenic molecules derived from bacterial cells or viruses
* Genetically engineered microbes or microbial antigens
## Footnote
These preparations are essential for effective vaccine development.
287
What is the process of **attenuation** in vaccine preparation?
Substantially lessening or negating the virulence of viruses or bacteria
## Footnote
Attenuation can be achieved through various methods, including long-term cultivation and genetic manipulation.
288
What are the primary advantages of **live attenuated vaccines**?
* Viable microorganisms can multiply and produce infection without disease
* Long-lasting protection
* Usually require fewer doses and boosters
## Footnote
Examples include vaccines for measles, mumps, polio, and rubella.
289
What are **acellular or subcellular vaccines** made from?
Bacterial cell parts
## Footnote
If derived from viruses, they are called antigen vaccines.
290
What are some examples of **extracted antigens** currently in use?
* Capsules of pneumococcus and meningococcus
* Protein surface antigen of anthrax
* Surface proteins of hepatitis B virus
## Footnote
These antigens can be isolated from cultures, produced by genetic engineering, or synthesized chemically.
291
What are the two types of **whole cell vaccines**?
* Killed cell vaccines
* Live, attenuated vaccines
## Footnote
Killed cell vaccines use heat or chemicals, while live, attenuated vaccines have reduced virulence.
292
What is the purpose of a **subunit vaccine**?
Stimulates immunity without causing disease
## Footnote
It uses isolated antigen molecules and does not contain intact pathogens.
293
What is a **recombinant vaccine**?
A vaccine made by isolating a gene for the antigen from the pathogen and splicing it into a plasmid
## Footnote
This process allows for the production of large amounts of viral surface antigen for vaccine preparation.
294
What is a **toxoid vaccine**?
A purified fragment of bacterial exotoxin that has been inactivated
## Footnote
Toxoid vaccines elicit the production of antitoxins to neutralize natural toxins, providing protection against diseases like diphtheria and tetanus.
295
Name two diseases for which no reliable vaccines are currently available.
* Malaria
* HIV/AIDS
## Footnote
Other diseases without functional vaccines include various diarrheal diseases and some respiratory diseases.
296
True or false: **Acellular vaccines** allow the pathogen to multiply and cause disease.
FALSE
## Footnote
Acellular vaccines stimulate immunity but do not allow the pathogen to multiply.
297
What is the role of **plasmids** in recombinant vaccine development?
They carry the gene that codes for the surface antigen
## Footnote
Plasmids are inserted into a cloning host to produce viral surface antigens.
298
What are the **indications** for toxoid vaccines?
* Diphtheria
* Tetanus
## Footnote
Toxoid vaccines provide protection against diseases caused by bacterial exotoxins.
299
What are the **biotechnology companies** using to mass produce vaccine antigens?
* Plants
* Tomatoes
* Potatoes
* Bananas
## Footnote
These plants synthesize proteins from cholera, hepatitis, papillomavirus, and E. coli pathogens.
300
What is the purpose of using **genetically engineered vaccines**?
* Design vaccines for obligate parasites
* Isolate genes encoding microbial antigens
* Insert genes into plasmid vectors
## Footnote
This method is effective for pathogens that are difficult or expensive to culture.
301
What does the **Trojan horse vaccine** technique involve?
* Inserting genetic material from an infectious agent into a non-pathogenic carrier microbe
* Multiplying the recombinant microbe
* Expressing foreign genes for immunization
## Footnote
Vaccinia and adenoviruses are practical agents for this technique.
302
What are **DNA vaccines** expected to do?
* Insert microbial DNA into plasmid vectors
* Human cells take up plasmids
* Express microbial DNA as proteins
## Footnote
These proteins trigger immune responses without causing an immune response themselves.
303
What are the **routes of administration** for most vaccines?
* Subcutaneous
* Intramuscular
* Intradermal
## Footnote
Oral vaccines are available for only a few diseases but have distinct advantages.
304
What is an **adjuvant**?
Any compound that enhances immunogenicity
## Footnote
It prolongs antigen retention at the injection site and helps improve vaccine effectiveness.
305
True or false: **Oral vaccines** are available for many diseases and are difficult to administer.
FALSE
## Footnote
Oral vaccines are easier to give, more readily accepted, and well tolerated.
306
List some diseases for which **DNA vaccines** are undergoing trials.
* Lyme disease
* Hepatitis C
* Herpes simplex
* Influenza
* Tuberculosis
* Papillomavirus
* Malaria
* SARS
## Footnote
These vaccines are being tested for their effectiveness and safety.
307
What is the role of **adjuvants** in vaccines?
Facilitates contact with antigen-presenting cells and lymphocytes
## Footnote
Common adjuvants include alum, Freund's complete adjuvant, and beeswax.
308
Vaccines must go through many years of trials in _______ and human volunteers before they are licensed for general use.
experimental animals
## Footnote
This ensures safety and efficacy before public distribution.
309
What are the **most common complications** of vaccines?
* Local reactions at the injection site
* Fever
* Allergies
* Other adverse reactions
## Footnote
These reactions are generally mild and resolve quickly.
310
Relatively rare reactions to vaccines occur at a rate of about one case out of _______ vaccinations.
300,000
## Footnote
Examples include panencephalitis from the measles vaccine and back-mutation from the polio vaccine.
311
What was the **whole-cell pertussis vaccine** replaced with due to adverse neurological effects?
acellular capsule (aP) form
## Footnote
This change was made to enhance safety in vaccination.
312
Professionals involved in vaccinations must understand their inherent risks but realize that the risks from the _______ almost always outweigh the chance of an adverse vaccine reaction.
infectious disease
## Footnote
This highlights the importance of vaccination in preventing disease.
313
What is the purpose of **vaccination** in public health?
To establish herd immunity
## Footnote
This protects nonimmune members of the population by reducing pathogen occurrence.
314
The most effective herd immunity outcome occurs when the **healthiest members** are vaccinated. True or False?
TRUE
## Footnote
Targeting the healthiest individuals enhances the overall immunity of the population.
315
Vaccination is considered a valuable factor in preventing _______.
epidemics
## Footnote
Herd immunity through mass immunization plays a crucial role in public health.
Microbiology
flashcards
Decks in class (36)
# Cards
-
Chemistry & Biochemistry49
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Ch 8 Metabolic109
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Ch. 13 Microbes131
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Ch, 4 Prokaryotes54
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Midterm Prep214
-
Ch 189
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Ch. 2104
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Ch. 489
-
Practice Test140
-
Scientific Disease Names10
-
Euk Vs Prok167
-
DNA Rep27
-
Lab Practicum19
-
Ch. 5 Eukaryotes245
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Ch. 6147
-
Ch. 9386
-
Test 2 Review132
-
#11-51 Cards31
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Ch. 7285
-
Ch. 11349
-
Ch. 12415
-
Extra 12450
-
Lab Review128
-
Lec 3 Review64
-
Ch 1456
-
Disease Cards 21-28, 52-6825
-
Disease Card Quiz177
-
Ch. 15315
-
Ch. 16319
-
Final Study Guide174
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#10-20137
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#21-31169
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#32-43155
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#44-54160
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#55-68211
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Ch 1748
