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WHAT is immunological tolerance and why is it important? |
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where in the body is tolerance induced and what are the major tolerance mechanisms? |
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how is immunological tolerance broken and what is the consequence? |
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Define: Immunological Tolerance |
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Definition
The (normal) situation whereby a person's immune system does not react to tissue constituents of that person's body. |
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Definition
An adaptive immune reaction against the body's own tissue resulting in autoimmune disease |
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what is central tolerance? |
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Definition
occurs during development of T and B cells |
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what is peripheral tolerance? |
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Definition
occurs in peripheral tissues after mature T and B cells have central lymphoid organs |
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what are the two types of immunological tolerance? |
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In central T cell tolerance, what cells control immune responses to antigens? |
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Definition
Autoimmune Polyendocrine Syndrome I |
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what causes disease in APS-I? |
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Definition
Recessive mutations in "AIRE." --> transcription factor for an autoimmune regulator. CD4+ T cells (and B cells) will then respond to various endocrine organs (ie, adrenal gland causing glucocorticoid insufficency). |
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what disorder is associated with APS-I ? |
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Definition
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which type of immunological tolerance (central v peripheral) is associated with APS-I? |
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what are the main mechanisms of peripheral T cell tolerance? |
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Definition
Activation-induced cell death (AICD), T cell anergy, Suppression by regulatory T cells |
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Definition
a lack of reaction by the body's defense mechanisms to foreign substances, and consists of a direct induction of peripheral lymphocyte tolerance |
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when AICD fails, what happens to the self-reactive T and B cell population? |
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Definition
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What does "ALPS" stand for? |
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Definition
Autoimmune Lymphoproliferative Syndrome |
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what InterLeukin is secreted when a CD4+ T cell runs into an antigen? |
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Definition
IL-2 that leads to clonal T cell expansion |
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what are the two possible causes of apoptosis when a T cell recognizes a self-antigen? |
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Definition
Lack of IL-2, and/or FasL expression |
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Definition
"death receptors" molecules for apoptosis |
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what characterizes T cell responses to self-antigens? |
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Definition
lack of (adequate) co-stimulation (eg B7). |
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what do you get when a T cell interacts with a self-antigen and gets co-stimulated (with B7)? |
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Definition
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what critical function do Foxp3 and IL-2 have when working together? |
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Definition
Inhibit mechanisms of T regulatory cells |
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Definition
Immune Dysregulation Polyendrocrinopathy Enteropathy X-Linked. |
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what is a mechanism causing IPEX syndrome? |
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Definition
Loss of function via mutations in FOXP3. |
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in which animal were FOXP3 mutations first discovered? |
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Definition
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why have B cell tolerance ? |
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Definition
Prevent responses mainly against T-independent self-antigens |
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what are two mechanisms of Central B cell tolerance? |
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Definition
Negative tolerance and editing of B cell receptor (IgM) |
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what happens to B cells with high antigen affinity while maturing in the bone marrow? |
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Definition
deleted! (negative selection) |
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what is going on in B cell receptor editing? |
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Definition
reactivation of Ig gene recombination and you get a new light chain paired with the old heavy chain. |
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what happens if an anergic B cell fails to enter B cell zone in lymph node? |
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Definition
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which cells have defective tolerance, thus leading to Auto-antibody-mediated diseases? |
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Definition
B cells and CD4+ T cells. |
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what 3 predisposing factors cause autoimmune disease? |
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Definition
genes, immune system, environment |
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what 3 genes can predispose to certain autoimmune diseases? |
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Definition
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what disease is AIRE associated with? |
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Definition
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what disease is Fas,FasL associated with? |
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Definition
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what disease is Foxp3 associated with? |
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