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17 Cards in this Set
- Front
- Back
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What is the product of an activated B cell?
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Antibody that protects against extracellular pathogens and toxins.
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What Igs do mature peripheral B cells express?
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IgM and IgD.
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What does it mean if an antigen is thymus dependent?
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The antigen requires CD4 T cells to help it activate the B cell.
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What happens in activation of a B cell that interacts with a thymus dependent antigen?
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B cell is activated by antigen cross-linking of membrane-bound Igs and interaction with CD4 T helper cells specific for the same antigen.
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Which epitopes do B cells and T cells recognize?
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B cells recognize conformation epitopes (the entire antigen) but T cells recognize peptide (linear) epitopes (pieces of the antigen).
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Once activated, what are the two fates of a B cell?
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1) Plasma cells that secrete low levels of IgM. 2) Daughters that can become high-affinity plasma cells (undergo heavy chain isotype switching and affinity maturation).
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What are the three Igs secreted by high-affinity plasma cells?
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IgA, IgG, and IgE.
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Secondary antibody response comes from __.
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Memory B cell.
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Secondary antibody response consists of what two Igs primarily?
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IgM and IgG.
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What is the purpose of booster shots?
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Secondary antibody response increases each time an antigen is encountered.
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How do thymus independent antigens stimulate B cells?
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Expression of repeating antigenic determinants.
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Describe B cells specific for thymus independent antigens with regard to Ig secretion, affinity, and memory B cell development,
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Secrete IgG and IgM, low affinity, do not develop into memory B cells.
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Why do infants generate poor antibody response to thymus independent antigens?
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Their immune systems are immature and lack repetition.
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Define hapten.
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Small chemical group that is antigenic (recognized as foreign) but only shows immunogenic (stimulates immune response) if linked to a protein carrier.
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Which cells recognize unbound haptens?
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B cells (more promiscuous).
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How are penicillin-specific antibodies produced?
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Pencillin binds to self proteins, forming a conjugate that the T cells recognize his altered self protein and active penicillin specific B cells to make IgE or IgG anti-penicillin Ab --> anti-penicillin Abs can cause rash, hemolytic anemia, or anaphylactic shock.
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Describe linked recognition.
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Combining a thymus independent cell with a thymus dependent cell, where the both are phagocytosed by the TI B cell but only TI pieces are displayed. Once displayed, this stimulates T cell recognition, and eradication of the TI antigen.
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