mastering 27
Th cells express a ________ protein coreceptor.
CD4
TC cells express a(n) ________ protein co-receptor.
CD8
Which event happens first during cytotoxic T-cell activation?
CD8 binds to MHC molecules of infected cells
Which of the following are found on the surfaces of all nucleated cells?
Class I MHC proteins
Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium?
Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria
What would a virally infected skin epithelial cell have on its cell surface?
Class I MHC with skin cell antigens
Which type of cell directly attacks infected cells?
Cytotoxic T-cells
HIV directly infects T-cells. Why is this problematic for cell-mediated immunity?
Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.
Which of the following are likely to be found on an MHC-I protein?
Damaged mitochondrial fragment
According to the animation, on which day does the production of IgG occur in the secondary response?
Day five
When does MHC-II loading occur?
During the fusion of vesicles containing MHC-II proteins with vesicles containing digested pathogens
What makes agglutination by antibodies possible?
Each antibody has at least two antigen-binding sites.
Tolerance is the acquired ability to make an adaptive immune response directed to self-antigens.
False
Which molecule triggers apoptosis?
Granzyme
Cytokines are produced by which of the following cells?
Helper T-cells
How do helper T-cells and cytotoxic T-cells work together?
Helper T-cells produce cytokines to activate other cells of the immune system.
What are the primary chemical mediators released from mast cells during an immediate-type hypersensitivity reaction?
Histamine and serotonin
Which part of the adaptive immune response involves B cells?
Humoral
Which of the following is NOT an immunoglobulin?
IgC
The most common circulating antibody, comprising about 80% of the serum immunoglobulin, is
IgG
In class switching during the secondary antibody response, the most common antibody switch in serum is from
IgM to IgG.
Which proteins on the antigen-presenting cell are recognized by the helper T-cell?
MHC proteins
Which of the cells listed below can present antigens on Class II MHC proteins?
Macrophages
Which cells are involved in a secondary response?
Memory B cells and plasma cells
Why would a body cell that is not a phagocyte need to present antigens?
Non-phagocytic body cells can become infected with a virus.
Where are MHC molecules located on a cell?
On the surface of the cell
Which structure do antigen presenting cells utilize to directly help them present bacterial antigens?
Phagolysosome
What is the role of plasma cells in humoral immunity?
Plasma cells produce antibodies.
T cells recognize antigens with their
T cell receptors
Antigen-presenting cells present antigens to
T lymphocytes.
Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell?
TCR
Natural killer cells are activated by
TH1 cells
According to the animation, for approximately how many days is IgG present in the serum?
Ten days
How might a pathogenic bacterium be affected by antibodies?
The antibodies may block proteins necessary for binding the pathogen to the host, may opsonize the bacterium, or may agglutinate bacteria.
Which organelle assists directly with the presentation of MHC-I antigens?
The endoplasmic reticulum
What is apoptosis?
The process of programmed cell death.
How is the secondary response different from the primary response in terms of antibody concentration in the blood?
The secondary response is faster and produces more antibodies than the primary response.
What is a feature of the small fragments presented by MHC-I proteins?
They are small peptides, roughly 8-10 amino acids long.
How do phagocytes communicate to other cells what they have captured?
They present antigens from engulfed foreign cells.
What is the fate of activated cytotoxic T-cells?
They proliferate into a clone of cells specific to the same antigen; some of these cells then differentiate into long-lived memory T-cells, while others mature to attack infected cells.
________ is the acquired inability to mount an adaptive immune response against self.
Tolerance
Tom has a genetic disorder in which he does not synthesize class I MHC proteins or functional NK cells. Which of the following statements would be true for Tom?
Tom would not be able to destroy virally-infected cells.
Self-reactive T cells are eliminated during the development of tolerance in the immune system.
True
The primary immune response involves
a slow rise in the concentration of antibodies, followed by a gradual decline.
An anamnestic response is
another name for secondary response.
A serum containing antigen-specific antibodies is called an
antiserum.
The measurable strength of the binding of an antibody to antigen is called
binding affinity.
Dimers of IgA are present in
breast milk colostrum, saliva, and tears.
Which of the following fluids contains secretory IgA?
breastmilk
According to the animation, on what day does IgM first appear?
day five
Which of the following is the name of the heavy chain constant domain of an IgD antibody?
delta
The part of the antigen recognized by the antibody or TCR is called the
epitope.
All antigens are immunogens.
false
Class I MHC proteins are found ONLY on the surface of B lymphocytes, macrophages, and dendritic cells.
false
Antibodies are a part of which type of immunity?
humoral
The purposeful artificial stimulation of active immunity to a particular infectious disease is known as
immunization.
Substances that induce an immune response are known as
immunogens.
Antigen processing and presentation
is a way for a cell to give information about its activities.
The use of antivenom to treat a snakebite is an example of artificial passive immunity.
true
Which of these is often used as a prophylactic measure to protect a person against future attack by a pathogen?
vaccination
Which is an example of acquisition of natural passive immunity?
A fetus protected from disease by its mother's antibodies
Antibodies are found in
milk, mucosal secretions, and serum.
The transfer of antibodies through the placenta from mother to fetus is an example of
natural passive immunity.
When do helper T-cells develop into TH1 or TH2 cells?
After proliferation into a clonal population
Natural killer cells like Tc cells use ________ and granzymes to kill their targets without prior exposure or contact with the foreign cells.
perforin
Some activated B cells differentiate into ________ cells that secrete antibodies, and others into ________ cells.
plasma / memory B
After the first exposure to an antigen, a ________ stimulates growth and multiplication of antigen-reactive cells.
primary adaptive immune response
TH2 cells produce cytokines that activate
B cells.
What is the function of the CD8 receptor?
Bind to MHC molecules
