Chapter 15 Smartbook
Opsonization can take place by binding of antigens with either _ produced by adaptive immunity or _ system proteins by innate immunity. Both outcomes increase the efficiency of phagocytosis
C3b; IgG
Penicillin is a hapten, meaning that it
Can react with proteins to form a penicillin-protein conjugate that can elicit an immune response
All B cells are initially programmed to differentiate into plasma cells that secrete IgM antibodies. It is only through ___ switching that they can shift to producing one of the other types.
Class
The stem of the Y-shaped antibodies has a highly
Conserved amino acid sequence that provides the "Red-flag" for other immune system components to eliminate the antigen
The type of molecule delivered by helper T cells was a signal
Cytokine
When a helper T cell recognizes a peptide presented to it by a B cell or macrophage, it delivers signals known as _ that activates the cell.
Cytokines
CD8
Cytotoxic T cell
T cells are activated by ________ cells, which can be considered the scout of the immune system.
Dendritic
Cross-presentation occurs when a
Dendritic cell that has ingested an antigen presents its to T cells on both MHC class I and class II molecules
Most antigens are T- _ , meaning that T-helper cells are required for confirmation.
Dependent
Most antigens are T- _, meaning that the T-helper cells are required for confirmation
Dependent
Unlike B and T cells, NK cells
Do not have antigen specific receptors
In the process of B cell activation, after the BCR has bound the antigen, the cell takes in the BCR and antigen complex via the process of
Endocytosis
Tc Cell
Endogenous antigen
Th Cell
Exogenous antigen
T or F IgM is the main circulating antibody in the bloodstream
False
True of false Unlike the situation in antibody heavy chains, antibody light chains do not undergo gene segment rearrangement
False
The constant region of an antibody molecule includes the entire ______ region, but also part of the two _________ regions.
Fc; variable
One of the traits of IgG molecules that gives them such a strong capacity for protective responses is their _- life of 21 days
Half
Antibody _ chain gene rearrangement processes are highly similar to those of the _ chains
Heavy, Light
The two main categories of T lymphocytes necessary to mount a response against foreign pathogens are cytotoxic T cells and ________ T cells.
Helper (Look for it to be rephrased)
CD4
Helper T cell
B cells in the mucosa-associated lymphoid tissues MALT would most commonly switch to _ production, providing mucosal immunity
IgA
B cells in the lymph nodes, producing antibodies for the blood and tissues, would most commonly switch to _ production
IgG
Newborns are protected by maternal_, which is present in the first breast milk, also called colostrum
IgG
The maternal immunoglobulin that protects the fetus and newborn is
IgG
B cells in the lymph nodes, producing antibodies for the blood and tissues, would most commonly switch to _ production. But B cells in the mucosa-associated lymphoid tissues (MALT) would most commonly switch to _ production, providing mucosal immunity.
IgG; IgA
Match each immunoglobulin class with its characteristics
IgM- Pentamer IgG- Crosses the placenta and therefore protects a developing fetus IgA-Component of breast milk, and therefore protects a breastfed infant IgE- Involved in many allergic reactions
When nucleotides are added or deleted as antibody gene segments are joined together, this is known as
Imprecise joining
A polysaccharide is a good example of a T-_ antigen because of its identical evenly spaced repeating epitopes
Independent
If B cells in the bone marrow with anti-self specific B cell receptors BCRs are not eliminated by the process of negative _, then autoimmune disorders might occur as the immune system gains the ability to make anti-self antibodies
selection
A polysaccharide is a good example of a possible T-independent antigen because
It possesses many repeating identical epitopes that can collectively activate a B cell without T cell help
Different varieties of antibody specific are created by
Joining together any combination that includes one V, one D, and one J segment. V20-D11-J3
A second mechanism that natural killer NK cells use to recognize target cells is recognition of a
Lower than normal MHC class I level on the target cell
Lymphatic vessels carry _ to the lymph nodes
Lymph, the extracellular fluid that might carry antigens into the lymph nodes
The primary cellular participants in the adaptive immune responses are
Lymphocytes
Positive selective in T cells permits only those that recognize _ molecules to develop further
MHC
Cytotoxic T cell
MHC class I
Helper T cell
MHC class II
Naive
Mature, but has not encountered antigen previously
Effector lymphocytes formed in secondary lymphoid organs
Migrate out to the site of the initial infection and respond as long as the antigen is present
An antigen interacting with a T cell receptor _______.
Must be broken down into peptide fragments and presented on an MHC molecule
A plasma cell typically survives
Only a few days
When antigen is introduced
Only the B cells capable of making the appropriate antibody can multiply
The cell type producing IgA is the
Plasma cell, particularly those in the MALT
MHC class molecules
Present only endogenous antigens
When a B cell processes and presents the antigen it recognized to a Th cell, it
Presents a variety of peptides from the antigen
The main function of TH cells is
Production of cytokines that direct and support other immune system cells.
Th17
Promote an effective response against extracellular invaders
Th2
Promote an effective response against helminths
Th1
Promoted an effective response against intracellular invaders
Th17
Promotes a response against extracellular pathogens
Th1
Promotes a response against intracellular pathogens
Th2
Promotes a response against multicellular pathogens
Lymph nodes and the spleen are both examples of _ lymphoid organs
Secondary
The process that B cells use to generate diversity in the B- cell receptors is
Similar to the process that T cells use to generate diversity in T cell receptors
B cell
Site of maturation is in the Bone Marrow
T cell
Site of maturation is in the Thymus
When an antigen is encountered for a second time later in life, there is a _ antigen-specific immune response called the _ response
Stronger; secondary
A _______ cell provides the second signal confirming that an antigen-activated B cell needs to start proliferation and differentiation into a plasma cell.
T
Processing and presentation of antigens is necessary for interaction with which type of lymphocyte antigen receptor?
T cell receptors
Young children are particularly suspectible to meningitis caused by Haemophillilus influenzae because the capsule of the bacterium is a _ antigen to which this age group response poorly
T- independent
If an immune system lost the ability to make T helper cells, the B cells could still be activated by
T-Independent antigens Polysaccarhides
A conjugate vaccine is composed of a polysaccharide attached to a protein, which converts a
T-independent antigen to a T- dependent antigen
Match the traits listed with either a B cell receptor or a T cell receptor
TCR - Each chain in the receptor has a single variable and dingle constant region domain - Composed of 2 polypeptide chains - Has only one peptide binding site BCR - Composed of 4 polypeptide chains - Light chains have a single variable and single constant region domain, while heavy chains have a single variable and multiple constant region domains - Has 2 peptide binding sites
Tolerance can be defined as
The ability of the immune system to selectively ignore certain molecules (especially "self" molecules)
When a T cell receptor interacts with an MHC molecule presenting an antigenic epitope, the TCR binds
To both the peptide and other portions of the MHC molecule as the two cells interact
The main outcome of B cell activation is
Triggering the cell to multiply
A immunogenic molecule is an antigen, but an antigen may not be immunogenic
True
T or F IgE attached to basophils and mast cells can also bind to normally harmless materials such as foods, dusts, and pollens, leading to allergic reactions
True
True or false? If a B cell presents antigen not recognized by any helper T cell, that B cell will become anergic.
True
How many heavy chain molecules are found in an antibody?
Two
The _________ region at the end of each arm of the Y-shaped antibody molecule is responsible for antigen binding.
Variable
When comparing two different antibody molecules that bind to different epitopes, the amino acid sequence in the _ region of each molecule will be different
Variable
A prime example of the protective actions of cytotoxic T cells TcCells can be found in attacks against
Virally infected self cells, inducing apoptosis
Neutralization prevents
Viruses and toxins from attaching to target cells and damaging them.
T cells that recognize a peptide presented by a dendritic cell, yet do not receive co-stimulatory molecule signals, will be induced to become
anergic
The presence of _ can initiate the classical pathway of complement activation
antibodies bound to antigen
Different subsets of effector helper T cells produce different _, thereby directing the immune system toward an appropriate response for a given antigen
cytokines
Tc cells encountering a target cell produce ___ that strengthen the immune response in nearby cells.
cytokines
Combinatorial diversity occurs when different fully formed anti body _ and _ chains are paired up with each other, yielding different specificites
light and heavy
Costimulatory molecules
- Are produced in increasing amounts on dendritic cells after they have collected microbial peptides and are migrating to lymph nodes - Are not initially produced on dendritic cells - Serve as "emergency lights" to let a T cell know that the antigen being presented is from a microbe
T-independent antigens
- Can activate B cells without T cell assistance - Possess long stretches of repeating subunits - Might be repeating polymers of carbohydrates - Might be lipid variants such as LPS
Positive selection mechanisms in lymphocytes occurs
- Due to binding of a TCR to MHC molecules during development and screening in the thymus - Only in T cells
Dendritic cells gather material by
- Extending tentacle-like extensive between epithelial cells to mucosal surfaces - Pinocytosis - Phagocytosis
What steps and outcomes are shared by macrophages and B cells seeking help from helper T cells?
- Helper T cells with the correct TCR bind to the peptide/MHC class II complex and deliver cytokines - Peptide fragments are loaded into MHC class II molecules for antigen presentation to helper T cells - Endocytosed antigens are broken down into peptide fragments - Antigens are brought into the cells by endocytosis
Affinity maturation
- Is a random process of spontaneous mutation - Occurs in B cells, allowing them to increase the binding-ability for their specific antigen over time - Is a form of natural selection among proliferating B cells
When a macrophage is activated,
- It gets larger - It begins producing nitric oxide - The number of lysosomes within it increase
Cell types capable of quickly binding up newly produced IgE include
- Mast cells - Basophils
Functions and characteristics of regulatory T cells include
- Suppression of activation of immune system responses against "self" - Possession of a TCR just like other T cells groups - Preventing manifestation diseases
A granuloma is composed of
- T cells - Macrophages
The cytokines delivered when a helper T cell comes into contact with a B cell presenting an antigen it recognizes leads to __________.
- activation of the B cell - proliferation of the B cell - formation of memory B cells - class switching in the B cell
An effector cytotoxic T cell should recognize presented antigen when the cell is displying peptide fragments of endogenous proteins that are _____.
Abnormal (cancerous) or non-self (replicating virus or microorganism) loaded into its MHC class I molecules.
A native T cell that recognizes antigen presented by a dendritic cell displaying co-stimulatory molecules can become
Activated
When a macrophage receives assistance from a helper T cell in the form of cytokines, it __________.
Activates more potent destructive mechanism for the cell, enhancing its antigen cleaning capacity
A plasma cell is
An antibody-producing descendant of a B cell
If a person lost the ability to make memory B cells, then the secondary response would be nearly identical to the _________
primary humoral response.
B cells
Antibody response
Without continuous stimulation by the presence of antigen, effector lymphocytes will undergo
Apoptosis
The function of IgD in blood serum
Are not well understood/ Have NOT been clearly defined
One way that natural killer NK cells identify target cells for antibody-dependent cellular cytotoxicity ADCC is
Binding to Fc regions of antibodies that have attached tot he target
An effector cytotoxic T cell (Tc) makes contact with its target by _____. As a result of the contact, it induces the cell to undergo poptosis.
Binding to antigenic peptide: MHC class I molecule compex
An antigen is a molecule capable of interacting with
- A B-cell receptor - An antibody molecule
The primary adaptive immune response
- Can take a week or longer to become fully protective - Produces "memory" to be used later on in subsequent exposures
What is the basic function of helper T cells
- Coordination of activities of B cells, macrophages, and other T cells - Activation of B cells - Activation of macrophages
Helper T cells orchestrate the immune response by
- Directing the activities of B cells, macrophages, and T cells - Activating B cells and macrophages
IgG
- Easily leaves the bloodstream and enters tissues - Accounts for 80-85% of circulating antibody levels
Cells that produce MHC class I molecules include
- Epithelial cells - B cells - Nerve cells - T cells
The five general types of constant regions give rise to five major classes of immunoglobulins (IG). These types include
- G - M - A - D - E
Secretory IgA is important in mucosal immunity and can be found in the mucosal membranes of the
- Genitourinary Tract - Respiratory Tract - Gastrointestinal Tract
Tolerance is crucial because it allows the immune system to
- Ignore harmless substances such as pollen and protein in foods - Ignore the body's own self molecules
Place the stages of lymphocyte development in order, with the earliest stage first
- Immature - Naive - Activated - Effector
The basic functions of effector cytotoxic cells (Tc cells) include
- Induction of apoptosis in infected self cells - Destruction of cancerous self cells
Place the steps that occur during the clonal selection process in the correct order.
- Lymphocytes gather in the secondary lymphoid organs - Antigens bind to lymphocytes that have a specific antigen receptor for an epitope on the antigen. - The lymphocytes being activated need the antigen as a first signal, but also a second signal to confirm the danger and allow activation. - When activation is confirmed, proliferation occurs. - Differentiation into effector cell form (plasma cell, helper T cell, Cytotoxix T cell) occurs.
Which of the following T cell events occur after activation?
- Proliferation of the newly activated cells. - Migration of effector cells out of the secondary lymphoid organ and to the site of infection. - Formation of memory cells. - Differentiation of the activated cells into effector cell forms.
Memory cells can speed up a secondary response because
- There are many of them - Class switching has already occurred, so the response is already fine-tuned for the antigen in question - Affinity maturation has already taken place, increasing the ability to bind antigen
Which of the following are possible fates of activated B cells in a primary response?
- They can differentiate into plasma cells - They can become memory B cells - They can proliferate
The three gene segments used to encode an antibody heave chain variable region are __________.
- Variable segments - Diversity segments - Joining segments
An epitope is
A small region of an antigen molecule that is the site of antibody binding
During an initial or primary exposure to an antigen, adaptive immunity generally takes about _ to build
A week
The main function of the lymphatic system is to allow _ to interact with and activate lymphocytes
Antigen
The term "Fab region" stands for "fragment of _ binding region"
Antigen
Antibodies binding to antigens can create large immune complexes because _______.
Each antibody can bind two separate but identical epitopes
Effector
Expresses specific traits that help eliminate invaders
Peyer's patches in the intestines ____________.
Facilitate contact between lymphocytes and antigens so that an effective adaptive response can occur
Activated
Has encountered antigen and can multiply because it has received the necessary signals to confirm that the antigen is a microbe or other harmful substance
IgG is the only antibody that is transported across the _ into the fetus's bloodstream.
Placenta
When memory B cells become reactivated in a secondary response, some rapidly form _____ cells to produce antibodies. Others begin undergoing _____ to produce an additional base of cells to work with.
Plasma; Proliferating
Match the traits to either primary or secondary responses
Primary - Slow to develop - Usually IgM in nature - Initially lacks affinity maturation: formed near the end of the response. - Initially lacks class switching; formed near the end of the response Secondary - Faster to develop due to preformed memory cells - Strong levels of affinity maturation already in place - Usually NOT IgM in nature - Class switching has already taken place
While the innate immune system responds to general molecular patterns associated with a variety of microbes, the adaptive response.
Produces multiple, highly specific individual responses to small subcomponents of individual microbes.
Lymphocytes in a secondary lymphoid organ that do not recognized their particular antigenic epitope
Remain active
The amino acid sequence of the end of the "arms" of different antibody molecules is
Variable, thus providing the basis for antibody specify to antigens
If antibodies bind to __________, structures on bacterial cells used for adherence, the bacteria aren't able to attach to host tissues and can be more easily washed away or targeted for destruction by immune responses.
pili
Humoral immunity is generally used to eliminate extracellular antigens such as
- Bacteria - Toxins - Viruses in tissue fluids
Lymphocytes mature in the primary lymphoid organs, B cells mature in the __, and T cells mature in the
- Bone Marrow - Thymus
Maternal IgG can protect a newborn after birth by
- Virtue of its long half-life it is present in the newborn's blood for nearly 6 months after birth. - Being present in colostrum, the first great milk produced after birth, supplementing the IgG carried in the newborn's blood after it is born.
A good analogy for the function of the secondary lymphoid organs is
A busy coffee shop where many cellular meetings take place
The main "weapon" that a Tc cell uses is
Induction of apoptosis
T cells
Interact with target cells and then cause changes in those cells
Due to the high specificity of antibody molecules for antigens and the wide array of antigens we may encounter in our typical lifespan, we need
Many different B cells because each one can interact with only one epitope.
Memory is an important trait of the adaptive immune process. Which diseases below will generally only occur in an individual once, priming a protective adaptive immune response that will provide the person with lifelong immunity?
Measles, Mumps and Diphtheria
_ Cells are responsible for the effectiveness of the secondary response
Memory
____ B cells are long lived and allow for a much faster response if the same antigen is encountered at a later date
Memory
Antibody-dependent cell-mediated cytotoxicity (ADCC) takes places when ________.
Natural killer cells bind the Fc region of antibodies coating an infected self-cell or tumor cell, and then induces that cell to undergo apoptosis
Cell-mediated immunity (CMI) deals with intracellular pathogens and antigens such as
Viruses replicating in a cell
A B cell receptor (BCR) is
A membrane bound version of the specific antibody that the particular B cell is programmed to produce
________________ cells, a large type of antigen-presenting cell, are responsible for initial activation of naive T lymphocytes in lymph nodes during a cell-mediated immune response.
Dendritic
Early on in an initial infection, __________ might be found in lymph draining into a lymph node.
Dendritic cells with processed antigensfree antigenswhite blood cells
In the classical pathway of complement system activation, the cascade of reactions is activated when a specific complement system protein attaches to __________.
side-by side Fc regions of antibodies bound to an antigen
