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Example Questions
Example Question #114 : Immune And Lymphatic Systems
Which of the following class of immunoglobulins is normally responsible for the promotion of the allergy response?
IgG
IgE
IgD
IgA
IgM
IgE
IgE plays a critical role in induction and promotion of type I hypersensitivity (allergy, asthma, etc.) normally through engagement of Fc receptors on the surface of basophils and mast cells, which primes them to produce large quantities of granules and chemical mediators (including histamines and cytokines).
Example Question #115 : Immune And Lymphatic Systems
Which is not a function of B cells?
Cytokine and chemokine production
Presentation of antigen to T cells
Antibody production
Ability to form memory cells
Secretion of extracellular traps
Secretion of extracellular traps
B cells play numerous integral roles in the immune response against foreign pathogens (viruses, bacteria, and fungi), including forming transient microenvironments called germinal centers, where they produce long-lived plasma cells that are high affinity for specific antigen and memory B cells. They also serve as antigen-presenting cells and producers of cytokines and chemokines; However, B cells are not able to produce extracellular traps, which primarily are composed of DNA and work to trap pathogens. Neutrophils produce extracellular traps.
Example Question #116 : Immune And Lymphatic Systems
Which cytokine is typically associated with the T helper 1 (Th1) response?
IFN-gamma
IL-4
IL-9
TGF-beta
IL-17
IFN-gamma
The following helper T cells are paired with the following cytokines:
Th1 - IFN-gamma
Th2 - IL-4
Th9 - IL-9
Th17 - IL-17
Tfh - IL-21
Example Question #117 : Immune And Lymphatic Systems
What is the group of diseases called when a person's immune system loses its ability to recognize its own MHC proteins?
Autoimmune
Allergies
Hypersensitivity
X-linked autosomal recessive diseases
X-linked lymphoproliferative disease
Autoimmune
Autoimmunity arises when one's immune system is unable to recognize its own MHC proteins, which could potentially lead to aberrant activation of the immune response. Furthermore, autoreactive immune cells that are normally induced to undergo apoptosis may be able to escape these tolerance mechanisms and induce tissue damage.
Example Question #118 : Immune And Lymphatic Systems
Which of the following cell types is considered to be part of the innate immune response?
Myocytes
T cells
Memory cells
NK cells
B cells
NK cells
Natural killer (NK) cells are prominent members of the initial innate immune response against foreign pathogens. They play numerous integral roles in the innate response including cytotoxic killing, cytokine production, and antibody-mediated cell cytotoxicity.
Example Question #121 : Immune And Lymphatic Systems
Which of the following group of cells are of the myeloid lineage?
All of the above
Some dendritic cells
B cells
NK cells
T cells
Some dendritic cells
Cells of myeloid lineage include dendritic cells, monocytes, macrophages, neutrophils, basophils, and eosinophils, while cells of lymphoid lineage include NK cells, B cells and T cells.
Example Question #122 : Immune And Lymphatic Systems
Which of the following statements is true?
Naive B cells need more than one signal to become activated towards a specific antigen.
Female sex hormones do not play an important role in the pathogenesis of autoimmune disease.
Healthy individuals do not have any B cells that are reactive against self-antigen.
In the prevention of autoimmunity, T cell tolerance is more critical than B cell tolerance against self-nuclear antigens.
The elimination of autoreactive lymphocytes during central tolerance is more important in the prevention of autoimmunity than peripheral tolerance.
Naive B cells need more than one signal to become activated towards a specific antigen.
Naive B cells (and most other immune cell subtypes) need more than one signal to become activated. They normally need B cell receptor signaling (signal 1), costimulation by other receptors (signal 2), and cytokines/chemokines (signal 3). This system is necessary in order to prevent aberrant activation of lymphocytes (safeguard against autoimmunity).
In regards to the other statements, there are numerous autoreactive B cells at any given time due to the stochastic nature of VDJ recombination and germinal center reactions. Therefore, tolerance mechanisms and checkpoints are incredibly important to keep these cells in check; central and peripheral tolerance are equally important. Self-nuclear reactive B cells and T cells are both necessary and critical in autoimmune pathogenesis. Female sex hormones are definitely believed to contribute greatly to autoimmune disease pathogenesis (e.g. estrogen). Over 75% of autoimmune patients are women.
Example Question #431 : Systems Biology And Tissue Types
Somatic hypermutation of B cell receptor (BCR) genes in immature, developing B lymphocytes generates numerous specificities that are useful against a specific foreign antigen, however the process generates many more specificities that are either low affinity or reactive against self-antigens. Tolerance mechanisms, which include apoptosis or anergy, are in place in the bone marrow to prevent these "non-useful" or "harmful" B cells from exiting. However, these checkpoints are not 100% accurate and numerous B cells with autoreactive BCR's leave and travel to secondary lymphoid tissues.
Tolerance checkpoints exist in secondary lymphoid tissues to purge the repertoire of low-affinity or autoreactive B cells. What is the tolerance checkpoint mechanism in the secondary lymphoid tissues referred to as?
Clonal deletion
Central tolerance
Clonal expansion
Peripheral tolerance
Affinity maturation
Peripheral tolerance
Peripheral tolerance is the correct term for the tolerance checkpoint mechanisms that are instituted in the secondary lymphoid organs such as spleen and lymph nodes. B cells with BCR specificities that are low affinity or reactive against self-nuclear antigen will be purged from the repertoire.
Example Question #101 : Immune System
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of tolerance to self antigens leading to the presence of high autoantibody titers. There are several underlying causes behind SLE, one of which is a dysregulation in the clearance of apoptotic cells, which can lead to secondary necrosis. This leads to the leakage of danger signals which contributes to the loss of peripheral tolerance and chronic inflammation.
A deficiency in the clearance of apoptotic cells can be attributed to which immune cell type?
Natural killer cells
Macrophages
Cytotoxic T cells
Plasma cells
Germinal center B cells
Macrophages
The defect in clearance of apoptotic cells in SLE is mainly attributed to macrophages, which serve integral roles in phagocytosis of dead cells and debris. An inability to clear these apoptotic cells over time leads to secondary necrosis, which results in the production and release of several DAMPS or damage-associated molecular pattern molecules which are potent inducers of the immune response.
Example Question #122 : Immune And Lymphatic Systems
Bone marrow chimeric mice are an invaluable tool used by immunologists to elucidate specific mechanisms of the immune response. The generation of these chimeras involve whole body irradiation to eliminate the mouse bone marrow followed by adoptive transfer of bone marrow from a donor mouse (usually transgenic).
One critical step in the successful generation of bone marrow chimeric mice involves the depletion of T cells from the donor bone marrow. Which of the following is reason for this necessary step?
All of these
The donor T cells may be activated by the MHC antigens from the recipient's cells, resulting in a graft versus host response.
The donor T cells are inherently defective in their ability to produce cytokines and growth factors needed in the bone marrow reconstitution.
The donor T cells are unable to reconstitute, proliferate, and mature in the recipient mouse.
The donor T cells have an inherently reduced cytotoxic killing ability.
The donor T cells may be activated by the MHC antigens from the recipient's cells, resulting in a graft versus host response.
T cells from the donor must be depleted due to the risk of incompatible MHC antigens on the recipient cells. If there is incompatibility, the donor T cells will attack and kill the host cells resulting in a graft versus host response.
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