Human Anatomy and Physiology : Immune Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #11 : Immune Physiology

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

A scientist is attempting to upregulate the activity of macrophages in a petri dish. The macrophages have already been exposed to bacterial pathogens. The addition of which chemical to the petri dish is most likely to enhance macrophage-mediated killing?

Possible Answers:

IFN-beta

Interleukin-5

IFN-gamma

IFN-alpha

Interleukin-2

Correct answer:

IFN-gamma

Explanation:

IFN-gamma is the main chemokine produced by CD4 T-cells to promote the oxidative killing of phagocytosed organisms in macrophages. Without IFN-gamma, macrophages can still ingest pathogens, though their killing efficiency will be far reduced.

Example Question #12 : Immune Physiology

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

Which of the following surface proteins is most likely to be used as a marker to distinguish T-lymphocytes from B-lymphocytes?

Possible Answers:

CD5

CD20

CD19

CD21

CD28

Correct answer:

CD28

Explanation:

The CD family of surface proteins (short for cluster of differentiation) is best understood as a set of nametags to distinguish one set of cells from another. CD28 is the most commonly used marker for T-cells, as it is unique to this cell type. In contrast, B-cells use a number of other unique markers, including CD20 and CD21, among others.

CD5 is used to distinguish chronic lymphocytic leukemia from other leukemic states.

Example Question #1 : Help With Proteins And Signals Of Adaptive Immunity

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

A team of physicians is preparing a patient for a bone marrow transplant. To prevent graft-versus-host disease, where the transplanted T-cells attack the host into which they have been introduced, the physicians make sure that the donor and host have a matching human leukocyte antigen (HLA) type.

Which HLA gene product interacts with receptors on CD8 T-cells most avidly?

Possible Answers:

Major histocompatibility complex II

B7

CD5

Major histocompatibility complex I

CD8

Correct answer:

Major histocompatibility complex I

Explanation:

The protein MHC I is present on the surface of all nucleated cells, and provides a means for cytotoxic CD8 T-cells to exert cell killing on any nucleated cell that becomes infected with a pathogen.

MHC II is a related protein, that is only present on antigen-presenting cells (APC). These antigen-presenting cells must interact with CD4 T-cells. As a result, we can make the generalization that CD4 T-cells interact with MHC II, restricted in expression to APCs, and CD8 T-cells interact with MHC I with far broader expression.

Example Question #1 : Help With Proteins And Signals Of Adaptive Immunity

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

Patients with clear cell carcinoma of the kidney often undergo therapy that uses an inflammatory cytokine to upregulate T-cell activity. Which of the following cytokines is most likely used as a treatmnt for clear cell carcinoma?

Possible Answers:

IL-5

IL-2

Interferon

IL-3

IL-8

Correct answer:

IL-2

Explanation:

IL-2 is the third signal that activates T-cell activity. T-cells are initially activated by MHC/T-cell receptor binding, and then the second B7 signal further primes activity. After these two signals, the T-cell produces its own IL-2, which acts in an autocrine fashion to further accelerate T-cell proliferation.

Example Question #13 : Immune Physiology

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

A scientist develops a protein that is able to interrupt the normal function of CD8 T-cells, preventing them from actively killing target cells. Except for actively killing targets, T-cells behave, physically bind to target cells, and develop normally after treatment with this protein. Which protein/receptor pair interaction on CD8 T-cells is most likley being interrupted by this protein?

Possible Answers:

Fas/Fas ligand

T-cell receptor/major hisotcompatibility complex I

CD-19/CD-19 receptor

IL-2/IL-2 receptor

CD28/B7

Correct answer:

Fas/Fas ligand

Explanation:

The interaction of Fas and Fas ligand is the most direct option among these choices that drives cell killing. The remainder of the options are either not relevant to T-cells, or are involved in simple binding or development. The interaction of Fas and its ligand actually drives cell death.

Example Question #421 : Systems Physiology

Which of the following attaches directly to pathogens to mark them for destruction?

Possible Answers:

B-cells

Antibodies

Macrophages

Plasma cells

T-cells

Correct answer:

Antibodies

Explanation:

Antibodies are produced by plasma cells (mature B-cells) with specific binding affinity for surface proteins that have been presented by antigen-presenting cells, like dendritic cells and macrophages. Once the plasma cell is stimulated by the presence of the specific antigen, it increases production of its antibody. These antibodies enter the blood and bind the antigen molecules on the surface of the pathogen cell. Cytotoxic T-cells and cytokines can then interact with the antibodies to initiate lysis of the infected cell or pathogen.

Example Question #12 : Adaptive Immunity

Which of the following statements is true?

Possible Answers:

Memory T-cells release antibodies in the event of infection by a previously encountered pathogen

A B-lymphocyte will release different antibodies until one of them attaches to an antigen

An antibody can attach to multiple antigens

B-lymphocytes have antibodies that attach to presented antigens

Correct answer:

B-lymphocytes have antibodies that attach to presented antigens

Explanation:

It helps to think of antigens and antibodies like a lock and key: they are highly specific for one another. B-lymphocytes create only one type of antibody. When this antibody attaches to an antigen presented by a macrophage or antigen-presenting cell, the B-lymphocyte will differentiate with the help of a helper T-cell. The result is replication of the B-lymphocyte to produce more of the same antibody from plasma cells and generate memory B-cells to easily respond in the event of a second infection by the pathogen.

Example Question #1 : Help With Antigens, Antibodies, And Mh Cs

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

After isotype switching facilitates the production of new serum antibody types by B-cells, an experiment shows that antibodies bind more tightly to pathogens. The researcher conducting the experiment concludes that these new antibodies are more efficient at interrupting infection than were the antibodies produced immediately following initial exposure to the pathogen. Which of the following is the most likely?

Possible Answers:

IgA was produced immediately after initial pathogen exposure, while IgG was produced after isotype switching

IgA was produced immediately after initial pathogen exposure, while IgM was produced after isotype switching

IgG was produced immediately after initial pathogen exposure, while IgM was produced after isotype switching

IgM was produced immediately after initial pathogen exposure, while IgA was produced after isotype switching

IgM was produced immediately after initial pathogen exposure, while IgG was produced after isotype switching

Correct answer:

IgM was produced immediately after initial pathogen exposure, while IgG was produced after isotype switching

Explanation:

The question specifies that the antibodies in question are serum antibodies, while IgA is primarily an antibody type secreted into luminal environments. As a result, we can conclude that IgA is not likely to be involved at all in this experiment. Beyond this, you must know that IgM is the type of antibody that is produced upon initial pathogen exposure. After CD4 cells facilitate isotype switching, IgG is produced and demonstrates more robust binding.

Example Question #1 : Help With Antigens, Antibodies, And Mh Cs

The human immune system is organized along two broad arms: innate immunity and adaptive immunity. The differences between these two approaches to immunity are not always black and white, but can be described in general terms with regard to immunological memory. Adaptive immunity displays this type of memory, and mounts a more intense response to pathogens upon second and subsequent exposures.

Within adaptive immunity, the system is further divided into humoral immunity and cell-mediated immunity. We can say that antibodies are the primary mediators of the former, while CD8 T-cell based cytotoxicity is the mediator of the latter.

CD4 T-cells, unlike their CD8 counterparts, are involved in both the humoral and cell-mediated arms of adaptive immunity. These CD4 cells drive isotype switching, a process that changes the types of antibodies produced after initial exposure to a pathogen to increase their molecular affinity. Additionally, CD4 cells promote the activity of macrophages to directly digest invading pathogens.

A scientist is conducting an experiment with a bacterial cell that stimulates an antibody response in mice. The scientist is able to isolate the particular region of the bacterial cell that generates the response and binds to the antibody. This portion of the bacterial cell is best described as the __________.

Possible Answers:

heavy chain

light chain

constant region

epitope

variable region

Correct answer:

epitope

Explanation:

The epitope is the region of a target cell to which an antibody binds. The remaining choices are all structural regions of the antibody itself, as opposed to the target cells to which an antibody binds.

Example Question #1181 : Human Anatomy And Physiology

Which antibody is able to cross the placenta? 

Possible Answers:

IgG 

IgM 

IgA

IgE

IgD 

Correct answer:

IgG 

Explanation:

IgG is the only class of immunoglobulin that is able to cross the placenta. This is important as this immunoglobulin is able to provide passive immunity to the unborn fetus

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