microbiology ch 12

How does adaptive immunity differ from innate immunity? A) Adaptive immunity generates immunological memory and its effects are immediate upon exposure to a pathogen. B) Adaptive immunity generates immunological memory and is specific to a pathogen. C) Adaptive immunity generates immunological memory. D) Adaptive immunity is specific to each pathogen. E) Adaptive immunity's effects are immediate upon exposure to a pathogen.

Adaptive immunity generates immunological memory and is specific to a pathogen.

Allorecognition occurs when B and T cells are screened for self-tolerance.

False

Artificial immunity is characterized by short-lived protection immune protection because the patient is not making their own memory cells or antibodies.

False

Both the cellular and humoral branches of adaptive immunity have the goal of eliminating an identified antigen, but only the humoral branch develops a memory of the antigen so that future responses are faster.

False

Isotype switching of antibodies is beneficial because some pathogens are able to alter their antigens.

False

T cell subclass differentiation allows T cell clones to recognize different epitopes of the same antigen.

False

The two-signal activation process for T cells includes A) interaction of the T-cell receptor with the MHC-antigen complex on the APC AND binding between co-stimulatory proteins on the T cell and APC surfaces. B) the presence of antibodies AND binding between co-stimulatory proteins on the T cell and APC surfaces. C) the presence of a superantigen and the presence of appropriate antibodies. D) interaction of the T-cell receptor with the MHC-antigen complex on the APC AND the presence of a superantigen. E) the presence of a superantigen AND binding between co-stimulatory proteins on the T cell and APC surfaces.

interaction of the T-cell receptor with the MHC-antigen complex on the APC AND binding between co-stimulatory proteins on the T cell and APC surfaces.

The cellular branch of adaptive immunity A) is based on the activity of both T and B cells. B) is organized by T cytotoxic cells and carried out by T helper cells. C) does not involve a memory function. D) is based on antibody production. E) is organized by T helper cells and carried out by T cytotoxic cells.

is organized by T helper cells and carried out by T cytotoxic cells.

All the following apply to B cells except A) originate in the bone marrow. B) reside in the lymphoid tissue. C) mature in the bone marrow. D) play a critical role in both the cellular and humoral responses. E) coordinate the humoral response by making antibodies.

play a critical role in both the cellular and humoral responses.

Consider a genetic mutation which causes T helper cells to be unable to respond to stimulation by the cytokines which lead to TH2 differentiation. This mutation would cause a patient to be deficient in which activity? A) production of memory cells B) action of cytotoxic T cells C) action of macrophage D) decrease of the immune response once the pathogen is eliminated E) production of antibodies

production of antibodies

While not a hard-and-fast rule, molecules may be ranked from more immunogenic to less immunogenic. Which shows the correct ranking form more immunogenic to less immunogenic? A) haptens > proteins > lipids > polysaccharides B) proteins > polysaccharides > lipids > haptens C) polysaccharides > lipids > proteins > haptens D) haptens > lipids > polysaccharides > proteins E) Only haptens are less immunogenic; lipids, polysaccharides, and proteins have about equal immunogenicity.

proteins > polysaccharides > lipids > haptens

In contrast to a primary immune response, immunological memory A) generates antibodies with enhanced affinity for its antigen. B) provides a rapid reactivation of both cellular and humoral responses. C) provides a rapid reactivation of humoral responses only by generating higher antibody titers and antibodies with increased affinity for its antigen. D) provides a rapid reactivation of both cellular and humoral responses including generating higher antibody titers and antibodies with increased affinity for its antigen. E) generates higher antibody titers.

provides a rapid reactivation of both cellular and humoral responses including generating higher antibody titers and antibodies with increased affinity for its antigen.

Cytotoxic T cells eliminate pathogens by A) releasing chemicals which are toxic to cellular pathogens. B) ingesting and digesting infected or cancerous cells. C) ingesting and digesting cellular pathogens. D) coordinating the activities of other immune cells. E) releasing chemicals which cause infected or cancerous cells to undergo apoptosis.

releasing chemicals which cause infected or cancerous cells to undergo apoptosis.

What is the role of memory cells? A) circulate in the body at elevated levels to maintain an active attack against any possible pathogen B) prevent an immune response against members of the normal microbiota C) remain in the lymphoid tissue to rapidly proliferate and differentiate upon subsequent exposure to the same pathogen D) provide immune protection specifically for central nervous system E) suppress the cellular response once the infection has passed

remain in the lymphoid tissue to rapidly proliferate and differentiate upon subsequent exposure to the same pathogen

The human immunodeficiency virus (HIV) selectively infects any cell which carries the CD4 surface glycoprotein. Which immune function will be impaired? A) stimulation of macrophage activity B) stimulation of B and Tc cells but not of macrophage C) stimulation of macrophage, B and TC cells D) stimulation of B cells and antibody production E) stimulation of Tc cells and destruction of virally-infected cells

stimulation of macrophage, B and TC cells

Which statement does not apply to haptens? A) Haptens must bind to a more complex molecule to stimulate an immune response. B) Haptens are also known as incomplete antigens. C) Antibiotics such as penicillin are often haptens. D) Haptens are generally too small to be immunogenic on their own. E) Haptens are any nonpathogenic substance, rather than a microorganism, which can stimulate an immune response.

Haptens are any nonpathogenic substance, rather than a microorganism, which can stimulate an immune response.

The branches of adaptive immunity are A) the cellular response and the memory response. B) the cellular response and the humoral response. C) the humoral response and the memory response. D) the antigen response and the memory response. E) the cellular response, the humoral response, and the memory response.

the cellular response and the humoral response.

The antibody found in breastmilk and coating mucous membranes is

IgA

The antibody class which is involved in fighting parasites is

IgE

The most abundant antibody class in the body, found in all body fluids, is

IgG

Generally, the first antibody class made upon a primary antigen exposure is

IgM

A newly-generated T cell can recognize MHCs and is not self-reactive. What is its fate? A) It is signaled for destruction via apoptosis. B) It will migrate to the bone marrow for screening for the ability to make antibodies against self-antigens. C) It will become part of an autoimmune attack in the body's tissues at some time in the future. D) It will undergo genetic shuffling to change its receptor to increase self-tolerance. E) It will migrate to the lymphoid tissues to await activation by its antigen.

It will migrate to the lymphoid tissues to await activation by its antigen.

What is the role of MHC I in the immune response? A) MHC I is found only on antigen-presenting cells and presents a sample of cellular proteins, including those of any intracellular pathogens, to T cells. B) MHC I is found only on antigen-presenting cells. C) MHC I is found on all body cells except red blood cells and presents a sample of cellular proteins, including those of any intracellular pathogens, to T cells. D) MHC I presents a sample of cellular proteins, including those of any intracellular pathogens, to T cells. E) MHC I is found on all body cells except red blood cells

MHC I is found on all body cells except red blood cells and presents a sample of cellular proteins, including those of any intracellular pathogens, to T cells.

Which statement is not true about MHC II? A) MHC II primarily displays extracellular antigens which have been phagocytized. B) MHC II is present only on antigen-presenting cells. C) When bound to antigen, MHC II serves a key role in activation of the appropriate T cells. D) MHC II interacts with the CD4 receptor on T helper cells. E) MHC II interacts with both the CD4 and CD8 receptors on T helper and T cytotoxic cells.

MHC II interacts with both the CD4 and CD8 receptors on T helper and T cytotoxic cells.

When "matching" a donated organ or tissue to a recipient, it is necessary that the ________ of the donor and the recipient be as similar as possible. A) MHCs B) T helper cells C) APCs D) blood type E) antibodies

MHCs

A patient antibody titer which shows an increasing level of IgM but very little IgG would likely indicate that A) the patient is having an allergic reaction. B) the patient was vaccinated against this pathogen rather than having the infection. C) the patient is in the early stages of developing an immune response. D) the patient has nearly recovered from the infection. E) the patient is currently a nursing mother.

the patient is in the early stages of developing an immune response.

Which statement is not true about T cell subclass differentiation? A) Regardless of which T helper cell subclass develops during an immune response, the humoral response is not impacted. B) T cell subclass differentiation is caused by the release of cytokines that is influenced by the antigen's nature and the amount present. C) Each subclass will include both effector and memory cells. D) Particular combinations of cytokines will favor the development of some T cell subclasses over others. E) Which specific T helper cell subclass that develops may impact the progression and outcome of an infectious disease.

Regardless of which T helper cell subclass develops during an immune response, the humoral response is not impacted.

Which T cell class is incorrectly matched with its description? A) Treg: ensures that immune responses subside once a threat subsides B) TH2: stimulate B cells to make antibodies C) TH1: stimulate TC cells D) TH: identified by the CD4 proteins on the cell surface E) TC: attack other T cells during self-tolerance screening

TC: attack other T cells during self-tolerance screening

Which statement provides the best explanation of the need for self-tolerance screening of lymphocytes? A) Lymphocytes which would attack the body's own tissues are never generated. B) The process which generates the vast array of diverse antigen receptors is a random process that could produce receptors which will bind to the body's own tissues. C) Self-tolerance involves "self" lymphocytes which bind to and form a protective layer over all body tissues. D) It is necessary to have some lymphocytes with receptors that are self-tolerant to respond to intracellular infections by viruses. E) The process which generates the vast array of diverse antigen receptors is a highly-controlled process, so the generation of receptors which can bind to the body's own tissues is a rare occurrence due to a genetic mutation.

The process which generates the vast array of diverse antigen receptors is a random process that could produce receptors which will bind to the body's own tissues.

A patient with a high antibody titer to a pathogen for which there is no vaccination indicates that this person is currently infected with the pathogen or was infected in the past.

True

An antigen may consist of multiple epitopes, each of which recognized by different lymphocytes.

True

Both the light and the heavy chains of an antibody are involved with epitope recognition and binding.

True

Graft-versus-host disease occurs when transplanted bone marrow gives rise to B and T cells that attack the recipient's tissues.

True

The humoral immune response can enhance phagocytosis by either direct interaction of antibodies with their antigen, or though antibody activation of the complement cascade.

True

The amount of antibody present in the blood is termed the antibody ________.

titer

What is the role of B cell receptors (BCRs) and T cell receptors (TCRs) in the immune response? A) to release the cytokines needs for immune cell stimulation B) to combine with haptens so they can stimulate an immune response C) to communicate with lymphocytes and other white blood cells D) to recognize specific epitopes of an antigen E) to release chemicals which destroy pathogens

to recognize specific epitopes of an antigen

How is the immune system able to recognize a limitless number of different antigens and epitopes? A) Each lymphocyte is coated with many different receptors, each of which recognizes a different epitope. B) Each lymphocyte is coated with many different receptors, each of which recognizes a different epitope AND the immune system produces a wide variety of lymphocytes. C) While each lymphocyte carries receptors that recognize only one type of epitope, the immune system produces a wide variety of lymphocytes each of which carries unique receptors. D) If a lymphocyte encounters an antigen it does not recognize, it immediately switches receptors until it finds one that is a match. E) A genetic "memory" of the pathogens your parents encountered (and their parents and so on) is passed on to each generation, increasing the number of possible responses over time.

While each lymphocyte carries receptors that recognize only one type of epitope, the immune system produces a wide variety of lymphocytes each of which carries unique receptors.

Isotype switching occurs when A) an antibody changes which class it is. B) a B cell changes which antibody class it is producing. C) a B cell switches which epitope it recognizes. D) an antibody changes epitope it can recognize. E) activated B cells differentiate into either plasma or memory cells.

a B cell changes which antibody class it is producing.

Antibodies do all the following except A) increase phagocytosis by agglutination of antigens. B) neutralize antigens to prevent binding to host cells. C) increase phagocytosis by opsonization. D) activate the complement cascade. E) activate killing by T cytotoxic cells.

activate killing by T cytotoxic cells.

By which means of acquiring immunity is likely to produce the longest lasting protection? A) artificial B) passive C) natural D) active E) Active, artificial, natural, and passive all provide equally long-lasting protection.

active

Postexposure prophylaxis, a form of artificial passive immunity, is often given when a person is bitten by an animal that is suspected of having rabies, or if the rabies-status of the animal cannot be confirmed. What specifically, is being given to the patient in this type of treatment? A) antigen-presenting cells which increase the rate at which the rabies antigens can be presented to T cells for activation B) effector B and T cells from a host who has developed an immune response to the rabies virus C) antibodies harvested from a host who has developed an immune response to the rabies virus D) memory cells from a host who has developed an immune response to the rabies virus E) antigens from the rabies virus

antibodies harvested from a host who has developed an immune response to the rabies virus

Which of the following is not required for T cell activation? A) bound antigen B) involvement of CD4 or CD8 C) co-stimulatory proteins D) antibody E) MHC I or II

antibody

A substance that may trigger an immune response, if presented in the right context is termed a(n) A) hapten. B) cytokine. C) antigen. D) antibody. E) effector.

antigen.

The difference between T cell activation by normal antigens and T cell activation by superantigens is that superantigens A) are not processed and presented by APCs and cause nonspecific activation of many T cells at once, including those that would not normally recognize the antigen. B) cause nonspecific activation of many T cells at once, including those that would not normally recognize the antigen and suppress cytokine release. C) suppress cytokine release. D) cause nonspecific activation of many T cells at once, including those that would not normally recognize the antigen. E) are not processed and presented by APCs.

are not processed and presented by APCs and cause nonspecific activation of many T cells at once, including those that would not normally recognize the antigen.

T-independent antigens A) are usually proteins. B) are able to bind multiple B cell receptors on a given B cell. C) are usually polysaccharides and able to bind multiple B cell receptors on a given B cell. D) may be polysaccharides or proteins, and are not able to bind multiple B cell receptors on a given B cell. E) are usually polysaccharides.

are usually polysaccharides and able to bind multiple B cell receptors on a given B cell.

Pregnant women are usually advised to be vaccinated against influenza to protect themselves and the baby after birth. The mother will acquire ________ immunity from the vaccine while the baby will acquire ________ immunity. A) artificial passive; artificial passive B) natural active; natural passive C) artificial active; artificial active D) artificial active; natural passive E) artificial active; artificial passive

artificial active; natural passive

Which is not a step in the process of B cell activation by a T-dependent antigen? A) interaction between co-stimulatory proteins on the B and T cells B) release of cytokines by the T helper cell provide the second activation signal for the B cell C) processing and displaying the antigen with MHC II on the B cell D) binding of the antigen to a T helper cell receptor E) binding of the antigen to the B cell receptor

binding of the antigen to a T helper cell receptor

All the following apply to T cells except A) originate in the bone marrow. B) reside in the lymphoid tissue. C) mature in the thymus. D) coordinate the humoral response by making antibodies. E) have the capacity to recognize virtually any type of antigen.

coordinate the humoral response by making antibodies.

IgE antibody, which is associated with allergic responses, A) is usually found circulating in the bloodstream. B) can be found bound to B cells. C) is resistant to destruction by stomach acid. D) encourages mast cells and basophils to release chemicals such as histamine and leukotrienes. E) is passed from mother to child through breastfeeding and may prevent the development of allergies in the child.

encourages mast cells and basophils to release chemicals such as histamine and leukotrienes.

Advantages of isotype switching include A) ability to respond to multiple epitopes of the same antigen with the same B cell and rapid response when a pathogen engages in antigen variation. B) ability to respond to multiple epitopes of the same antigen with the same B cell. C) rapid response when a pathogen engages in antigen variation. D) ability to respond to multiple epitopes of the same antigen with the same B cell, expanded antibody response as different isotypes predominate in different areas of the body, and rapid response when a pathogen engages in antigen variation. E) expanded antibody response as different isotypes predominate in different areas of the body.

expanded antibody response as different isotypes predominate in different areas of the body.