Chapter 18 Multiple Choice

Describe the mechanism of antibody-dependent cell-mediated cytotoxicity.

Antibodies produced by B cells bind to target antigens on the surface of pathogens too large for phagocytosis, coating the pathogens. This leaves the Fc region of the antibodies exposed and available for binding NK cells, macrophages, or eosinophils. When these cells bind to the Fc regions of the antibodies through their Fc receptors, they release toxic substances that kill the target pathogens.

A patient is bitten by a dog with confirmed rabies infection. After treating the bite wound, the physician injects the patient with antibodies that are specific for the rabies virus to prevent the development of an active infection. This is an example of: Artificial passive immunity Artificial active immunity Natural passive immunity Natural active immunity

Artificial passive immunity

Match each type of vaccine with the corresponding example: conjugate

Capsule polysaccharide bound to a protein

Cellular adaptive immunity is carried out by _________. T cells bone marrow B cells neutrophils

T cells

What is a superantigen? -a protein that activates T cells in a nonspecific and uncontrolled manner -a protein produced by T cells as a way of increasing the antigen activation they receive from antigen-presenting cells -a protein that is highly efficient at stimulating a single type of productive and specific T cell response -a protein produced by antigen-presenting cells to enhance their presentation capabilities

a protein that activates T cells in a nonspecific and uncontrolled manner

The variable regions of the heavy and light chains form the __________ sites of an antibody.

antigen binding

Which of the following does NOT occur during the lag period of the primary antibody response? -binding of antigen to BCRs -class switching to IgG -presentation of antigen with MHC II -activation of helper T cells

class switching to IgG

Peripheral tolerance mechanisms function on T cells after they mature and exit the _________.

thymus

A TCR is a protein dimer embedded in the plasma membrane of a T cell. The ________ region of each of the two protein chains is what gives it the capability to bind to a presented antigen.

variable

MHC II molecules are made up of two subunits (α and β) of approximately equal size, whereas MHC I molecules consist of a larger α subunit and a smaller subunit called ______.

β2 microglobulin

What is the difference between an antigen and a hapten?

An antigen has many epitopes and is capable of inducing an adaptive immune response. A hapten is a much smaller molecule that is not antigenic on its own but can become antigenic when conjugated to a larger carrier protein.

What necessary interactions are required for activation of helper T cells and activation/effector function of cytotoxic T cells?

Both classes of T cells must recognize foreign epitopes with their TCR; the epitope must be associated with MHC I (cytotoxic T cell) or MHC II (helper T cell) molecules. The T cells must also recognize "self" during the interaction through CD4 anchoring to MHC II for helper T cells and CD8 anchoring to MHC I for cytotoxic T cells.

Which pathway of antigen presentation would be used to present antigens from an extracellular bacterial infection?

Extracellular bacteria would be ingested via phagocytosis by an APC. After destruction of the bacterial cell and processing of bacterial antigens in the phagolysosome, the most antigenic or immunodominant antigens would be presented in association with MHC II.

Cytotoxic T cells will bind with their TCR to which of the following? -antigens presented with MHC II molecules -haptens only -antigens presented with MHC I molecules -free antigen in a soluble form

antigens presented with MHC I molecules

To what does the TCR of a helper T cell bind? -antigens presented with MHC II molecules -antigens presented with MHC I molecules -free antigen in a soluble form -haptens only

antigens presented with MHC II molecules

________ immunity occurs when antibodies from one individual are harvested and given to another to protect against disease or treat active disease.

artificial passive

A(n) ___________ pathogen is in a weakened state; it is still capable of stimulating an immune response but does not cause a disease.

attenuated

Match the example to the type of immunity being acquired: natural active

being ill and recovering from an infection

Match the example to the type of immunity being acquired: artificial passive

blood transfusion from someone previously infected with a pathogen

Match the example to the type of immunity being acquired: natural passive

breastfeeding

A ________ molecule is a glycoprotein used to identify and distinguish white blood cells. -MHC I -cluster of differentiation -B-cell receptor -T-cell receptor

cluster of differentiation

The heavy chains of an antibody molecule contain ________ region segments, which help to determine its class or isotype.

constant

A ________ T cell will become activated by presentation of foreign antigen associated with an MHC I molecule.

cytotoxic

A single antigen molecule may be composed of many individual _____________. T cell receptors B cell receptors epitotes MHC II

epitotes

A ________ T cell will become activated by presentation of foreign antigen in association with an MHC II molecule.

helper

________ immunity involves the production of antibody molecules that bind to specific antigens

humoral

T-independent antigens can stimulate B cells to become activated and secrete antibodies without assistance from helper T cells. These antigens possess ___________ antigenic epitopes that cross-link BCRs.

repetitive

What is the basic difference in effector function between helper and cytotoxic T cells?

Helper cells release cytokines that stimulate other cells of adaptive and innate immunity to enhance their killing of pathogens. Cytotoxic T cells are the effector cells of cellular immunity that induce apoptosis of infected target cells.

What is the difference between humoral and cellular adaptive immunity?

Humoral immunity involves the production of antibodies by B cells and the targeting of pathogens and toxins in the extracellular environment. Cellular immunity targets intracellular pathogens through direct cell-to-cell interactions involving T cells.

A patient lacks the ability to make functioning T cells because of a genetic disorder. Would this patient's B cells be able to produce antibodies in response to an infection? Explain your answer.

If the pathogen causing the infection has T-independent antigens, then the patient's B cells could be activated by the T-independent mechanism and produce IgM antibodies to combat the infection. However, if the pathogen has only protein antigens, which are T-dependent, then the patient's B cells would not be activated and thus would not produce antibodies.

Which of the following would be a BCR? MHC I MHC II CD4 IgD

IgD

Match each type of vaccine with the corresponding example: inactivated vaccine

Influenza virusmunogenic particles are particles grown in chicken eggs are harvested and chemically treated to render them noninfectious. These ime then purified and packaged and administered as an injection.

Which type of antigen-presenting molecule is found on all nucleated cells? B cell receptors MHC I Antibodies MHC II

MHC I

Which type of antigen-presenting molecule is foundonly on macrophages, dendritic cells, and B cells? T cell receptor B cell receptor MHC II MHC I

MHC II

A patient gets a cold, and recovers a few days later. The patient's classmates come down with the same cold roughly a week later, but the original patient does not get the same cold again. This is an example of: Natural active immunity Artificial passive immunity Natural passive immunity Artificial active immunity

Natural active immunity

Briefly compare the pros and cons of inactivated versus live attenuated vaccines.

Pros: Live attenuated vaccines stimulate both humoral and cell-mediated adaptive immunity and can be given in smaller doses. Inactivated vaccines are easy to store and transport, and are not associated with risks of active disease or reversion to original virulence. Cons: Live attenuated vaccines may cause serious disease in immunocompromised individuals or may revert to virulent forms causing disease in immunocompetent individuals. They also present challenges for long-term storage and transport. Inactivated vaccines may require larger doses and multiple doses, increasing the risk of side effects.

________ antigens can stimulate B cells to become activated but require cytokine assistance delivered by helper T cells.

T dependent

Name the T helper cell subset involved in antibody production. CTL TH2 TH1 TH17

TH2

Match each type of vaccine with the corresponding example: toxoid vaccine

Tetanus toxin molecules are harvested and chemically treated to render them harmless. They are then injected into a patient's arm.

Match each type of vaccine with the corresponding example: subunit vaccine

The gene for hepatitis B virus surface antigen is inserted into a yeast genome. The modified yeast is grown and the virus protein is produced, harvested, purified, and used in a vaccine.

Match the example to the type of immunity being acquired: artificial active

receiving a vaccine

IgA description

This class of antibody is found in very large amounts in mucus secretions.

IgE description

This class of antibody is involved in the defense against parasitic infections and involved in allergic responses.

IgD description

This class of antibody is not secreted by B cells but is expressed on the surface of naïve B cells

IgM description

This class of antibody is the first to appear after activation of B cells

IgG description

This class of antibody is the only one that can cross the placenta.

Which mechanism of antigen presentation would be used to present antigens from a cell infected with a virus?

Viruses are intracellular pathogens. Viral proteins produced during replication are processed in the cytoplasm by proteasomes and presented in association with MHC I to T cells.

Match each type of vaccine with the corresponding example: live attenuated vaccine

Weakened influenza virions that can only replicate in the slightly lower temperatures of the nasal passages are sprayed into the nose. They do not cause serious flu symptoms, but still produce an active infection that induces a protective adaptive immune response.

Both ________ and effector T cells are produced during differentiation of activated T cells.

memory

There are two critically important aspects of adaptive immunity. The first is specificity, while the second is ________.

memory

Antibodies are produced by ________. T cells B cells bone marrow plasma cells

plasma cells

MHC molecules are used for antigen ________ to T cells.

presentation

MHC II molecules present ____________ processed self-antigens from proteasomes. processed foreign antigens from phagolysosomes. antibodies T cell receptors.

processed foreign antigens from phagolysosomes.

MHC I molecules present ___________ processed self-antigens from phagolysosome. T cell antigens antibodies processed self-antigens from proteasomes.

processed self-antigens from proteasomes.

Which of the following would be a T-dependent antigen? glycolipid lipopolysaccharide carbohydrate protein

protein

Which class of molecules is the most antigenic? proteins lipids carbohydrates polysaccharides

proteins