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32 Cards in this Set
- Front
- Back
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What is an immunogen?
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any substance that can induce a cell-mediated or humoral immune response
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What is an antigen?
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a substance that is recognized by a particular surface Ig or TCR and is a target of an immune response
all Ags are immunogens but not all immunogens are Ags |
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What is a hapten? Give an example.
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a small molecule which can elicit an immune response only when attached to a large carrier such as a protein
ex. urushiol, a toxin found in poison ivy |
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The best immunogens are what?
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LARGE proteins
the most foreign to the host, the better the immunogen |
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What factors affect the response to immunogens?
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1. Amount of immunogen - excessively large doses can lead to tolerance, too little will not elicit a response
2. Route of exposure 3. Genotype of recipient - the type of MHC, B-cell and T-cell genes will influence the degree of reactivity 4. Repetition - boosting leads to increase response 5. Administration with other immunogens or adjuvants can alter the immune response |
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What is an adjuvant?
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substances that when mixed with and co-injected with Ag enhance the immunogenicity of that Ag
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What is the only adjuvant approved for human use by the FDA?
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alum
causes time of exposure to Ag to increase from days to weeks increases the size of Ag making it amenable to phagocytosis |
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What are the 5 immunoglobulin classes?
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IgM, IgG, IgE, IgA, IgD
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What is the major Ig in normal human serum?
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IgG
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What is the second Ab made in response to infection?
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IgG
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What immunoglobulin(s) can cross the placenta?
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IgG
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What is the first Ab made in response to an infection?
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IgM
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What immunoglobulin(s) contain a J chain?
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IgM, IgA
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Membrane bound and secreted IgM exist as what?
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membrane bound - monomer
secreted - pentamer |
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When is IgA activated?
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when the gut is exposed to Salmonella, cholera, gonorrhea, etc.
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Where can secretory IgA be found?
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breast milk, saliva, tears, mucus
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Which immunoglobulin is more susceptible to proteolysis?
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IgD
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What is the function of IgD?
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function is unknown
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Where can IgE be found and where is it scarce?
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found on surface of basophils and mast cells
scarce in serum |
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What is the function of IgE?
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associated with allergies and may play a role in immunity to helminthic parasites
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What is an assay for IgE activity?
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Prausnitz and Kustner reaction (wheel and flare rxn)
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What are the 3 classes of epitopes?
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1. Isotypic
2. Allotypic 3. Idiotypic |
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Describe isotypic epitopes.
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found in constant region
define each heavy chain class and subclass within a species, each normal individual will express all isotypes in the serum |
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Describe allotypic epitopes.
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subtle amino acid differences that occur in some but not all members of a species
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Describe idiotypic epitopes.
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generated by conformation of the amino acid sequences of the heavy and light chain variable regions
each Ab has multiple idiotypes the sum of which is called the idiotype of the Ab |
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Valency of an Ab refers to what?
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the number of antigenic determinants that an individual Ab can bind (at least 2 and sometimes more)
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What is included in the basic structure of Igs?
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2 heavy and 2 light chains
disulfide bonds for stability variable and constant regions hinge region (flexible) oligosaccharides on constant heavy region |
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What breaks Abs into 3 pieces: FAB, FAB, and Fc
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papain
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What is the function of FAB?
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these fragments contain the Ag binding sites of the Ab
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What is the function of Fc?
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the effector functions of Igs are mediated by this part of the molecule
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Where is the Fc receptor located?
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on all effector cells of the immune system: NK cells, macrophages, neutrophils, mast cells, B cells, etc.
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What is the function of the Fc receptor?
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binds to Abs that are attached to infected cells or invading pathogens thereby helping in the elimination and identification of microbial pathogens
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