Microbiology Ch 17 - Study 1

At a minimum, the human immune system is capable of recognizing approximately how many different antigens? 1020 1015 1010 105 1025

1015

Which of the following are likely to be found on an MHC-I protein? A. Damaged mitochondrial fragment B. Membranes from a neighboring dead host cell C. Bacterial cell wall fragment D. Bacterial DNA E. Bacterial flagella

A. Damaged mitochondrial fragment

When does MHC-II loading occur? A. During the fusion of vesicles containing MHC-II proteins with vesicles containing digested pathogens B. During phagocytosis of an invading pathogen C. During viral infection D. After passing through the endoplasmic reticulum

A. During the fusion of vesicles containing MHC-II proteins with vesicles containing digested pathogens

Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell? A. TCR B. CD4 C. IL-2 Receptors D. IL-1 Receptors

A. TCR

In the figure, which areas are different for all IgM antibodies? A. a and b B. a and c C. b and c D. c and d

A. a and b

__________________ stimulated with ___________ differentiate into __________, which secrete antibodies into the bloodstream. A. Plasma cells, antigen, B-cells B. B-cells, antigen, plasma cells C. Phagocytes, antigen, B-cells D. Antigen, plasma cells, B-cells

B. B-cells, antigen, plasma cells

HIV directly infects T-cells. Why is this problematic for cell-mediated immunity? A. HIV transforms the T-cells into cancer cells. B. Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body. C. HIV causes cytokines to be produced at much higher levels, altering the normal function of the immune system. D. HIV reprograms these cells to attack the body cells.

B. Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

Which of the following WBCs are NOT lymphocytes? A. NK cells B. M cells C. cytotoxic T cells D. helper T cells E. B cells

B. M cells

What is a feature of the small fragments presented by MHC-I proteins? A. They are small fragments of nucleic acids, 8-10 nucleotides in length. B. They are small peptides, roughly 8-10 amino acids long. C. They are large proteins from the host. D. They are derived from bacteria.

B. They are small peptides, roughly 8-10 amino acids long.

A Treg cell deficiency could result in A. increased number of viral infections. B. autoimmunity. C. increased severity of bacterial infections. D. increased number of bacterial infections. E. transplant rejection.

B. autoimmunity.

Which of the following destroys virus-infected cells? A. dendritic cells B. Treg C. CTL D. TH E. B cells

C. CTL

For pathogen below, choose the type of cell that would be used in the adaptive immune response. Fungi and Extracellular Bacteria A. B cells B. TH1 cells C. TH17 cells D. TH2 cells

C. TH17 cells

How might a pathogenic bacterium be affected by antibodies? A. The antibodies may block proteins necessary for binding the pathogen to the host. B. The antibodies may coat the surface of the bacteria (opsonization), allowing for it to be tagged for phagocytosis. C. The antibodies may block proteins necessary for binding the pathogen to the host, may opsonize the bacterium, or may agglutinate bacteria. D. The antibodies may stick to multiple bacteria, causing agglutination.

C. The antibodies may block proteins necessary for binding the pathogen to the host, may opsonize the bacterium, or may agglutinate bacteria.

Which of the following best characterizes clonal selection? A. The production of identical B cells producing different antibodies B. The production of different antigens by the same B cell C. The production of identical B cells producing the same antibody D. The production of identical T cells producing the same antibody

C. The production of identical B cells producing the same antibody

The primary immune response involves A. a slow rise in the concentration of antibodies, followed by a rapid decline. B. an immediate increase in the concentration of antibodies, followed by an immediate and sharp decline. C. a slow rise in the concentration of antibodies, followed by a gradual decline. D. an immediate increase in the concentration of antibodies, followed by a slow decline.

C. a slow rise in the concentration of antibodies, followed by a gradual decline.

Phagocytosis is a process for engulfing large particles (>1μm). Which feature of antibodies will help to make particles larger, therefore enhancing phagocytosis? A. opsonization B. neutralization C. agglutination D. complement activation

C. agglutination

Plasma cells are activated by a(n) A. B cell. B. APC. C. antigen. D. T cell. E. memory cell.

C. antigen.

TH2 cells produce cytokines that activate A. cytotoxic T-cells. B. macrophages. C. natural killer cells. D. B cells.

D. B cells.

Which of the following statements concerning cellular immunity is FALSE? A. T cells respond to antigens when the antigens bind to receptors on their surface. B. The lymphocytes involved with cellular immunity are found primarily in lymphoid organs and blood. C. The thymus is necessary for development of cells involved in cellular immunity. D. Cellular immunity involves cells that recognize antigens and make specific antibodies against them.

D. Cellular immunity involves cells that recognize antigens and make specific antibodies against them.

In the figure, which areas are similar for all IgG antibodies? A. a and b B. a and c C. b and c D. c and d E. b and d

D. c and d

According to the animation, on what day does IgM first appear? Day fifteen Day ten Day five Day one

Day five

What is the fate of activated cytotoxic T-cells? A. Each activated cytotoxic T-cell proliferates, forming a clone of cells specific to the same antigen. B. They are destroyed via apoptosis. C. They are infected by viruses. D. They can differentiate into long-lived memory T-cells. E. 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. F. They can mature and attack infected cells.

E. 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.

Based on the animation, T cells recognized the antigen displayed by what protein of the B cell? TCR CD4 MHC Antigen BCR

MHC

Number 21

Number 22

According to the animation, for approximately how many days is IgG present in the serum? Five days Ten days Twenty days Fifteen days

Ten days

In the figure, which letter on the graph indicates the patient's secondary response to an antigen? a b c d e

c

Where are MHC molecules located on a cell? A. In the nucleus B. Inside the cell cytoplasm C. They are not associated with any one location on the cell D. On the surface of the cell

D. On the surface of the cell

The following events elicit an antibody response. What is the third step? A. TH cell produces cytokines. B. Antigen-digest goes to surface of APC. C. B cell is activated. D. TH cell recognizes antigen-digest and MHC II. E. APC phagocytizes antigen.

D. TH cell recognizes antigen-digest and MHC II.

For pathogen below, choose the type of cell that would be used in the adaptive immune response. Helminth A. TH17 cells B. B cells C. TH1 cells D. TH2 cells

D. TH2 cells

Which of the following statements is FALSE? A. The variable region of a heavy chain binds with antigen. B. The Fc region attaches to a host cell. C. The variable region of a light chain binds with antigen. D. The constant region of a heavy chain is the same for all antibodies. E. All of the answers are correct.

D. The constant region of a heavy chain is the same for all antibodies.

How is the secondary response different from the primary response in terms of antibody concentration in the blood? A. The secondary response is slower, but produces more antibodies than the primary response. B. The secondary response is faster, but does not produce more antibodies than the primary response. C. There is no difference with regard to antibody concentration in the blood. D. The secondary response is faster and produces more antibodies than the primary response.

D. The secondary response is faster and produces more antibodies than the primary response.

Which of the following is NOT a characteristic of B cells? A. They are responsible for the memory response. B. They have antibodies on their surfaces. C. They originate in bone marrow. D. They recognize antigens associated with MHC I. E. They are responsible for antibody formation.

D. They recognize antigens associated with MHC I.

If a patient has been exposed to an antigen for the first time, which class of immunoglobulin appears first? IgG IgE IgM IgD

IgM

The presence of which of the following indicates a current infection rather than a previous infection or vaccination? IgG IgE IgM IgA IgD

IgM

In addition to IgG, the antibodies that can fix complement are IgA. None of the answers is correct. IgM. IgD. IgE.

IgM.

Large antibodies that agglutinate antigens are IgG. IgM. IgA. IgD. IgE.

IgM.

The implementation of vaccinations occurred prior to experimental support for the germ theory of disease. True False

True

In the figure, what can attach to a host cell? b and c a and c b a and d e

e

In the figure, which letter on the graph indicates the highest antibody titer during the patients response to a second antigen? a b c d e

e

Number 10

...

The variable region of the antibody is solely responsible the significant diversity of antigen targets. True False

False

Order the steps in the clonal expansion of antibodies and the production of antibodies.

1. Using its TCR, the Th cell recognizes the viral epitope displayed by the B cell. 2. Cytokines produced by the Th cell activate the B cell, which divides giving rise to two cell types - memory cells and plasma cells. 3. Plasma cells secrete antibodies that recognize the virus.

If this particular antigen attempts to re-infect Caleb, it's in for a bigger fight. By getting activation of adaptive immune cells such as B-cells and T-cells, the body generates an extra layer of protection. What is a critical advantage for Caleb the next time he encounters this antigen? A. Anamnestic (memory) responses and future vaccinations to augment the response B. Rates of ear infections (otitis media) are decreasing in the U.S. C. Innate immune components will be more abundant and quicker to respond D. Total immunity to the antigen once exposed and defeated by the body E. New, more potent antibiotics may be available as therapeutics to minimize need for immune responses

A. Anamnestic (memory) responses and future vaccinations to augment the response The major difference between innate responses and adaptive responses is the formation of memory cells Innate cells respond the same way each time. They search for simple antigenic patterns (pathogen-associated molecular patterns or PAMPs) and act on those patterns, and one cell can detect and respond to multiple antigens. Adaptive cells are specific for a single molecular pattern and tend to act even more effectively each time they encounter it.

According to the animation, on which day does the production of IgG occur in the secondary response? A. Day five B. Day two C. Day ten D. Day fifteen

A. Day five

How can a sufficient humoral immune response occur if a plasma cell only lives for a few days? A. Each plasma cell can produce up to 2000 antibodies every second. B. T cells can also produce antibodies. C. Memory B cells can also produce antibodies. D. Each plasma cell can proliferate into more plasma cells.

A. Each plasma cell can produce up to 2000 antibodies every second.

Immune cells that secrete cytokines and activate other immune cells are: A. Helper T-cells B. Abnormal body cells C. Cytotoxic T-cells D. Virally infected cells E. Invading pathogenic bacteria

A. Helper T-cells

Most patients would happily accept a prescription for antibiotics from the pediatrician and go home. But as a microbiologist, Dr. Trapper wanted to identify the infectious etiology and see what was going on inside his son. Even though it's not standard procedure for otitis media, he asked for some of the fluid contained behind the eardrum to be collected with a syringe (tympanocentesis) so he could analyze it for culture and sensitivity in his lab. He stained the fluid and examined it under the microscopic field. Interestingly, although he did not find any noticeable bacterial organisms, he did find high numbers of this characteristic responding cell type (picture), which could likely be identified as a: A. Neutrophil B. Macrophage C. Plasma cell D. Natural killer (NK) cell E. Dendritic cell

A. Neutrophil The appearance of the nucleus and cytoplasm of these cells would identify them as neutrophils (a.k.a. "polymorphonuclear leukocytes" or PMNs). They are part of the innate class of cells known as "granulocytes" which comprise a large percentage of responding innate cells. Increasing numbers of neutrophils, known as leukocytosis or "raised white blood cell counts" are often clinically important for diagnosis of acute bacterial infection, especially pyogenic infection. Often, these can be seen on common hospital lab reports as "bands" or "shifts". These terms refer to immature neutrophils that are released from reserves in the bone marrow because they are needed to battle invading bacteria. Because they have not had enough time to 'grow up' they can be distinguished by phenotype and quantified. Neutrophils are some of the "first responder cells" that migrate the area of infection and their death results in the production of pus as noted in our patient, Caleb.

Which structure do antigen presenting cells utilize to directly help them present bacterial antigens? A. Phagolysosome B. Mitochondria C. Golgi apparatus D. Nucleus

A. Phagolysosome

Which organelle assists directly with the presentation of MHC-I antigens? A. The endoplasmic reticulum B. The nucleus C. The Golgi apparatus D. The mitochondria E. The phagosome

A. The endoplasmic reticulum

Which of the following statements concerning immunological memory is true? A. The memory response is due to production of long-lived cells that can respond very rapidly upon second exposure. B. Antibodies produced in response to a secondary infection are mostly IgM. C. The memory response involves only B cells. D. The memory response is usually faster but not as strong.

A. The memory response is due to production of long-lived cells that can respond very rapidly upon second exposure.

What is apoptosis? A. The process of programmed cell death. B. The proliferation of cytotoxic T-cells. C. The receptor on a cytotoxic T-cell that recognizes MHC molecules. D. A protein molecule that forms a pore in the membranes of infected cells.

A. The process of programmed cell death.

Which of the following statements about natural killer cells is FALSE? A. They are stimulated by an antigen. B. They destroy tumor cells. C. They destroy cells lacking MHC I. D. They destroy virus-infected cells. E. None of the answers are correct; all of these statements are true.

A. They are stimulated by an antigen.

When haptens attach to carrier molecules, an epitope forms on hapten which then can be bound to antibody. True False

False

How do phagocytes communicate to other cells what they have captured? A. They present antigens from engulfed foreign cells. B. They engulf virally infected cells. C. They spread viruses to other cells.

A. They present antigens from engulfed foreign cells.

In the figure, which areas represent antigen-binding sites? A. a and b B. a and c C. b and c D. c and d E. b and d

A. a and b

An anamnestic response is A. another name for secondary response. B. another name for primary response. C. the appearance of antibodies in serum. D. the term used to describe the production of antibodies from a plasma cell.

A. another name for secondary response.

Which of the following statements is NOT a possible outcome of antigen-antibody reaction? A. clonal deletion B. ADCC C. activation of complement D. agglutination E. opsonization

A. clonal deletion

Thymic selection A. destroys T cells that do not recognize self-molecules of MHC. B. activates B cells. C. destroys B cells that make antibodies against self. D. destroys CD4+ cells that attack self. E. destroys MHC molecules.

A. destroys T cells that do not recognize self-molecules of MHC.

ADCC is a process that is most effective in destroying A. eukaryotic pathogens. B. bacterial pathogens. C. bacterial toxins. D. extracellular viruses. E. virus-infected host cells.

A. eukaryotic pathogens.

Antigen processing and presentation A. is a way for a cell to give information about its activities. B. is only accomplished by bacterial cells. C. is a way for viruses to infect cells. D. is the way foreign cells engulf macrophages.

A. is a way for a cell to give information about its activities.

Which type of adaptive immunity does the following statement describe? This type of immunity is acquired when antigens enter the body and an infection occurs. The immune system works to fight the infection via the innate and adaptive immune responses and creates an immunological memory of that particular antigen. A. naturally acquired active immunity B. naturally acquired passive immunity C. artificially acquired passive immunity D. artificially acquired active immunity

A. naturally acquired active immunity

When an antibody binds to a toxin, the resulting action is referred to as A. neutralization. B. ADCC. C. agglutination. D. opsonization. E. apoptosis.

A. neutralization.

Which cytokines are believed to contribute to autoimmune disease, such as rheumatoid arthritis? A. tumor necrosis factor (TNF) B. interferons C. hematopoietic cytokines D. chemokines

A. tumor necrosis factor (TNF) The tumor necrosis factor (TNF) family of cytokines are the ones that help to protect against tumors but also play a role in some autoimmune diseases.

Caleb recovered without incident, but because there are millions of cases of ear infections every year in the U.S., Dr. Trapper wanted to make sure that this would not be the first of many recurrent ear infections for his son. He wanted to ensure that Caleb did not have an underlying immunodeficiency that would cause his future responses to fight antigens suboptimally. He asked the physician to do a serology analysis of Caleb, which consisted of probing for each antibody isotype found and to report how much is present. The analysis yielded the following results. What might you conclude from this? Probe Qualitative Result Anti-whole human antiserum +++ Anti-IgG ++ Anti-IgA ++ Anti-IgM + A. Caleb has a B cell deficiency B. Caleb has a normal response C. Caleb has SCID D. Caleb has a T cell deficiency E. Caleb has an autoimmune disorder

B. Caleb has a normal response Caleb's antibody response is perfect and producing as predicted! As the immune response progresses, we hope our responses become specialized to best combat the antigen. This includes adaptive immune activation and eventual memory responses. When we have T cell help (from CD4+ T cells) and plasma B cell responses, we fine-tune the response to make more productive antibody types. These changes produce better-qualified antibodies to bind the antigen via clonal selection and immunoglobulin class switching. Caleb's data shows he is producing large amounts of the efficient antibody, IgG, instead of the inefficient "rookie" antibody IgM.

While we usually think of fever as a bad thing, a fever is actually signifying that an immune response is progressing! Overall, which of the following cytokines would be most involved in increasing Caleb's fever response? A. Interleukin-4 B. Interleukin-1 C. Interleukin-2 D. Interleukin-10 E. Interleukin-12

B. Interleukin-1 When immune cells sense pathogens, certain components of the pathogen stimulate the innate cells to produce cytokines. When Interleukin-1 is produced, it acts on the hypothalamus to "crank up the heat" and results in fever and increased inflammatory processes. The other cytokines listed have separate functions such as T-cell responses (Interleukin-2), B-cell responses (Interleukin -4), anti-inflammation (Interleukin -10), or cell differentiation (Interleukin -12).

What is produced by the process of clonal expansion? A. Plasma cells B. Plasma cells and memory B cells C. Memory B cells D. Plasma cells, T cells, and memory B cells

B. Plasma cells and memory B cells

What is the role of plasma cells in humoral immunity? A. Plasma cells neutralize toxins. B. Plasma cells produce antibodies. C. Plasma cells engulf viruses. D. Plasma cells are phagocytes. E. Plasma cells activate the complement system.

B. Plasma cells produce antibodies.

An antigen that is potent enough to activate a B cell on its own is known as A. antibodies. B. T-independent antigens. C. T-dependent antigens. D. BCR.

B. T-independent antigens.

The following events occur in cellular immunity. What is the third step? A. Dendritic cell takes up antigen. B. TH cells proliferate. C. Antibodies are produced. D. Antigen enters M cell. E. TH cell produces cytokines.

B. TH cells proliferate.

For pathogen below, choose the type of cell that would be used in the adaptive immune response. Intracellular bacteria and protozoa A. TH2 cells B. TH1 cells C. TH17 cells D. B cells

B. TH1 cells

Which type of T cell is involved in activating macrophages and stimulating development of cytotoxic T cells? A. TH2 cells B. TH1 cells C. CD8+ T cells D. Treg cells

B. TH1 cells

Natural killer cells are activated by A. TH2 cells. B. TH1 cells. C. antigen-presenting cells. D. bacterial cells.

B. TH1 cells.

Which of the following statements concerning antigen-presenting cells is true? A. They are a type of T cell. B. They are involved in activating T cells. C. They transport antigens to the liver, where they can be degraded. D. They are found only in lymphoid tissues.

B. They are involved in activating T cells.

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? A. Tom would be less susceptible to helminth infections. B. Tom would not be able to destroy virally-infected cells. C. Tom would not be able to produce antibodies against viruses. D. Tom would be more susceptible to bacterial infections.

B. Tom would not be able to destroy virally-infected cells.

Which of the following is the best definition of antigen? A. something foreign in the body B. a chemical that elicits an antibody response and can combine with these antibodies C. a pathogen D. a chemical that combines with antibodies E. a protein that combines with antibodies

B. a chemical that elicits an antibody response and can combine with these antibodies

Which type of adaptive immunity does the following statement describe? This type of immunity is acquired when a person is vaccinated for a specific type of infection via the introduction of antigens. These antigens normally have undergone some type of modification and may not confer the same type of long-lasting memory that would occur with unmodified antigens. A. artificially acquired passive immunity B. artificially acquired active immunity C. naturally acquired passive immunity D. naturally acquired active immunity

B. artificially acquired active immunity

What type of immunity results from recovery from mumps? A. innate immunity B. naturally acquired active immunity C. naturally acquired passive immunity D. artificially acquired active immunity E. artificially acquired passive immunity

B. naturally acquired active immunity

The flu virus mutates fairly frequently. Its adhesive proteins change such that we have different "strains" of influenza each year. When a particular flu virus mutates such that its adhesive proteins change, which function of antibodies is disrupted? A. opsonization B. neutralization C. complement activation D. agglutination

B. neutralization

What is the correct sequence of events for activation of a B cell by a T-dependent antigen? A. The T cells binds to an antibody on the B cell. The T cell secretes cytokines. The B cell binds the antigen. The B cell is activated by binding to the antigen. B. The B cell binds to a cytokine and then interacts with the TH cell. This causes the B cell to bind the antigen, and then the B cell is activated. C. (1) Immunoglobulin receptors on the B cell recognize and bind the antigen. (2) An antigen fragment in complex with MHC class 2 is displayed on the B cell's surface. (3) The MHC-antigen complex binds a receptor on a TH cell. (4) The TH cell secretes cytokines that activate the B cell. D. Identical repeating subunits on the antigen bind to many of the antibodies on the surface of the B cell. This activates the B cell.

C. (1) Immunoglobulin receptors on the B cell recognize and bind the antigen. (2) An antigen fragment in complex with MHC class 2 is displayed on the B cell's surface. (3) The MHC-antigen complex binds a receptor on a TH cell. (4) The TH cell secretes cytokines that activate the B cell.

Dr. Trapper wasn't going to give up easily and continued to scan the overall field for bacterial clues, but all he found were more immune cells. Soon, he noticed something else interesting...several cells were interacting! The likely identities of these cells based on morphologies could be best described as: A. Activated B cell and an antibody producing cell B. Macrophage and a platelet cell C. Adaptive immune cell and an antigen presenting cell D. Neutrophil and a complement cell E. "Killer" cell and an infected eardrum cell

C. Adaptive immune cell and an antigen presenting cell This interaction represents a critical turn in the immune response. The cell on the right (grey) is likely a lymphocyte, a component of the adaptive lines of defense. The cell on the left (purple) is an innate cell, likely a dendritic cell. This is probably representative of the interaction of an antigen-presenting cell (APC). The result of antigen presentation is to activate and bring powerful adaptive cells like B cells and T cells into the fight and provides tertiary immune responses such as antibody production (B cells), cytotoxicity (CD8 T cells), or 'helper/coordination' (CD4 T cells) functions. Without this APC interaction, the third line of defense would be inactive in our plight against antigen and our overall responses would suffer. Most other choices can be ruled out due to the phenotypic appearances.

When do helper T-cells develop into TH1 or TH2 cells? A. Before autostimulation B. Immediately after the binding of the CD4 receptor C. After proliferation into a clonal population D. After B cell activation

C. After proliferation into a clonal population

What makes agglutination by antibodies possible? A. Antibodies can recognize bacteria as well as viruses. B. Antibodies can inactivate toxins. C. Each antibody has at least two antigen-binding sites. D. Antibodies are produced by plasma cells.

C. Each antibody has at least two antigen-binding sites.

Which of the following is the most likely possible diagnosis for Caleb? A. Sinus infection B. Flu C. Ear infection D. Common cold E. Mumps

C. Ear infection Hopefully, you recognized the signs and symptoms of an "ear infection" (otitis media, OM): pain and pressure in the ears or head, fever, and feeling "wiggly," which we later deduced to be a 4-yr-old's way of describing the imbalance and dizziness he felt from his inner ear dysfunction! OM is responsible for millions of pediatric infections per year.

Which molecule triggers apoptosis? A. Gamma-interferon B. MHC C. Granzyme D. Perforin E. IL-2

C. Granzyme

Antibodies are a part of which type of immunity? A. Cell-mediated B. Neither humoral nor cell-mediated C. Humoral D. Both humoral and cell-mediated

C. Humoral

Which of the following statements about IL-12 is FALSE? A. It activates the TH1 pathway. B. It inhibits some tumor cells. C. It causes autoimmune diseases. D. It activates macrophages. E. It causes TH cells to respond to HIV.

C. It causes autoimmune diseases.

Which proteins on the antigen-presenting cell are recognized by the helper T-cell? A. IL-2 receptors B. CD8 receptors C. MHC proteins D. IL-1 receptors

C. MHC proteins

Which cells are involved in a secondary response? A. Memory B cells B. Plasma cells C. Memory B cells and plasma cells D. T cells

C. Memory B cells and plasma cells

Why would a body cell that is not a phagocyte need to present antigens? A. Antigens are infectious and can spread to normal cells. B. Antigens are required for cell-to-cell attachment. C. Non-phagocytic body cells can become infected with a virus. D. All cells of the body can engulf invading cells.

C. Non-phagocytic body cells can become infected with a virus.

Which of the following recognizes antigens displayed on host cells with MHC II? A. B cell B. TC cell C. TH cell D. natural killer cell E. basophil

C. TH cell

Consider a helminthic infection in which an individual is colonized by a parasitic worm. The worm is too big to be engulfed by a phagocytic cell. How does the immune system respond? A. Blood flow is reduced to the area, which starves the worm of nutrients. B. Antibodies bind to the worm and disrupt its plasma membrane. C. The worm gets coated with antibodies, which activate other cells in the immune system to secrete chemicals that kill it. D. Numerous phagocytes work cooperatively to ingest the worm.

C. The worm gets coated with antibodies, which activate other cells in the immune system to secrete chemicals that kill it.

Which of the following cells is NOT an APC? A. dentritic cells B. macrophages C. natural killer cells D. immature B cells E. None of the answers is correct; all of these are APCs.

C. natural killer cells

Newborns' immunity due to the transfer of antibodies across the placenta is an example of A. innate immunity. B. naturally acquired active immunity. C. naturally acquired passive immunity. D. artificially acquired active immunity. E. artificially acquired passive immunity.

C. naturally acquired passive immunity.

Which of the following is NOT a characteristic of cellular immunity? A. It can inhibit the immune response. B. Cells are processed in the thymus gland. C. T cells react with antigens. D. B cells make antibodies. E. The cells originate in bone marrow.

D. B cells make antibodies.

What is the function of the CD8 receptor? A. Produce gamma interferon B. Activate cytokines C. Produce IL-2 D. Bind to MHC molecules

D. Bind to MHC molecules

Which event happens first during cytotoxic T-cell activation? A. Clonal proliferation B. Secretion of granzymes and perforin C. Production of IL-2 and gamma-interferon receptors D. CD8 binds to MHC molecules of infected cells

D. CD8 binds to MHC molecules of infected cells

Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium? A. Class II MHC with dendritic cell antigens B. Class I MHC with dendritic cell antigens C. Class II MHC with engulfed bacterial antigens D. Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria

D. 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? A. Class II MHC with viral antigens B. Class II MHC with macrophage antigens C. Class II MHC with liver cell antigens D. Class I MHC with skin cell antigens

D. Class I MHC with skin cell antigens

Which type of cell directly attacks infected cells? A. Bacterial cells B. Cancerous cells C. Helper T-cells D. Cytotoxic T-cells

D. Cytotoxic T-cells

How do helper T-cells and cytotoxic T-cells work together? A. Helper T-cells produce cytotoxic T-cells. B. Cytotoxic T-cells produce cytokines to activate helper T-cells. C. Cytotoxic T-cells attack abnormal body cells, while helper T-cells attack virally infected cells. D. Helper T-cells produce cytokines to activate other cells of the immune system.

D. Helper T-cells produce cytokines to activate other cells of the immune system.

Which part of the adaptive immune response involves B cells? A. Both humoral and cell-mediated B. Neither humoral nor cell-mediated C. Cell-mediated D. Humoral

D. Humoral

Which of the cells listed below can present antigens on Class II MHC proteins? A. Virus infected epithelial cells B. Healthy epithelial cells C. Tumor cells D. Macrophages

D. Macrophages

The examination led to a diagnosis of otitis media (OM), or an ear infection. The picture on the left demonstrates a swollen, red eardrum with a fluid buildup behind the membrane. The immune processes most involved in the inflammation seen behind Caleb's eardrum would be attributed to: A. Lysis of red blood cells and allergic responses against platelets B. Destruction of all leukocytes and sudden cytokine storm responses C. Uncontrolled tissue necrosis due to pathogenic immune responses D. Vasodilation of capillaries and accumulation of immune cells, fluid or pus E. Reducing edema factors and increasing intravascular coagulation

D. Vasodilation of capillaries and accumulation of immune cells, fluid or pus The acute inflammatory processes provide noticeable signs, symptoms, and clinical clues such as pain, heat, and swelling to show that the body is attempting to fight the pathogen. This manifests when vasodilation increases blood flow to the area and produces erythema and edema. Specifically, edema is the result of the increased permeability of post-capillary venules as signaled by inflammatory cytokines and allows immune cells and microbe-fighting proteins to arrive at the area.

Cytokines released by TH1 cells A. convert B cells to T cells. B. convert TH1 cells to TH2 cells. C. convert TH2 cells to TH1 cells. D. activate CD8+ cells to CTLs. E. kill parasites.

D. activate CD8+ cells to CTLs.

What type of immunity results from vaccination? A. innate immunity B. naturally acquired active immunity C. naturally acquired passive immunity D. artificially acquired active immunity E. artificially acquired passive immunity

D. artificially acquired active immunity

Which type of adaptive immunity does the following statement describe? This type of immunity is acquired via injection of antibodies from an individual or host that has immunological memory to the specific pathogen or antigen. A. artificially acquired active immunity B. naturally acquired active immunity C. naturally acquired passive immunity D. artificially acquired passive immunity

D. artificially acquired passive immunity

Which of the following bacterial components would most likely result in B cell stimulation by T-independent antigens? A. flagellum B. plasmid C. pili D. capsule E. ribosome

D. capsule

CD4+ T cells are activated by A. complement. B. cytokines released by dendritic cells. C. interaction between TCRs and MHC II. D. interaction between CD4+ and MHC II. E. cytokines released by B cells.

D. interaction between CD4+ and MHC II.

An antibody's Fc region can be bound by A. B cells. B. CTLs. C. T helper cells. D. macrophages. E. antibodies.

D. macrophages.

An individual may be exposed to a pathogen and become infected without actually getting sick. This is known as a subclinical infection. Even in subclinical infections, the individual's adaptive immune system can generate memory for the pathogen. What type of adaptive immunity is this? A. naturally acquired passive immunity B. artificially acquired active immunity C. artificially acquired passive immunity D. naturally acquired active immunity

D. naturally acquired active immunity

Which type of adaptive immunity does the following statement describe? This type of immunity is acquired via the passing of antibodies from a mother to a child to give immunity during the development of the child's immune system. A. artificially acquired passive immunity B. naturally acquired active immunity C. artificially acquired active immunity D. naturally acquired passive immunity

D. naturally acquired passive immunity

Which one of the following causes transmembrane channels in target cells? A. IL-1 B. IL-2 C. hapten D. perforin E. granzymes

D. perforin

In the figure, the arrow at time (c) indicates A. exposure to a new antigen. B. the T-cell response. C. the time of exposure to the same antigen as at time (a). D. the secondary response. E. the primary response.

D. the secondary response.

What type of immunity results from transfer of antibodies from one individual to a susceptible individual by means of injection? A. innate immunity B. naturally acquired active immunity C. naturally acquired passive immunity D. artificially acquired active immunity E. artificially acquired passive immunity

E. artificially acquired passive immunity

Which of the following is the best definition of epitope? A. specific regions on antigens that interact with MHC class molecules B. specific regions on antigens that interact with perforins C. specific regions on antigens that interact with haptens D. specific regions on antigens that interact with T-cell receptors E. specific regions on antigens that interact with antibodies

E. specific regions on antigens that interact with antibodies

IL-2, produced by TH cells, A. activates antigen-presenting cells. B. activates TC cells to CTLs. C. activates macrophages. D. causes phagocytosis. E. stimulates Th cell maturation

E. stimulates Th cell maturation

The specificity of an antibody is due to A. its valence. B. the H chains. C. the L chains. D. the constant portions of the H and L chains. E. the variable portions of the H and L chains.

E. the variable portions of the H and L chains.

The production of interferons at an infection site is critical for chemotaxis. True False

False

Apoptosis results in significant leakage of cellular contents. True False

False

Memory cells do not require B cell receptors. True False

False

Only dendritic cells produce interleukins. True False

False

Plasma cells will eventually differentiate into memory cells. True False

False

The antibodies found in mucus, saliva, and tears are IgG. IgM. IgA. IgD. IgE.

IgA.

The antibodies found on the surface of B cells, and which always exist as monomers, are IgG. IgM. IgA. IgD. IgE.

IgD.

The antibodies that can bind to large parasites are IgG. IgM. IgA. IgD. IgE.

IgE.

Which immunoglobulin class, found in blood, lymph, and the intestine, can cross the placenta and help to protect a fetus? IgA IgM IgG IgE

IgG

The most abundant class of antibodies in serum is IgG. IgM. IgA. IgD. IgE.

IgG.

Cytokine storms negatively impact human health. True False

True

Cytokines are protein-based chemical messengers that allow for communication between cells of the immune system. True False

True