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30 Cards in this Set
- Front
- Back
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Fab Antibody Part
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Top half of the Y shaped antibody
-the antigen binding site -contains the variable region |
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Fc Antibody Part
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Constant fragment
-lower half of the antibody |
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Variable Region
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-Region at the tip of the antibody
-includes light and heavy chains -antigen binds to the cleft in this region |
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Constant Region
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-Differ in different antibodies but they are not variable
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Light and Heavy Chains
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-disulfide bonded together
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Neutralization
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-antibody binds to the surface of the virus and inhibits it from binding to the host cell receptors
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Agglutination
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-needed for phagocytosis so it will be bigger
-pathogens and toxins are binded into a large clump because antibodies have 2 binding site and bacterial cells have multiple binding site also |
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Opsonization
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-C3B opsonin and antibodies
-phagocyte recognizes Fc part of antibodies and enhance phagocytosis |
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ADCC
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Antibody-Dependent Cellular Cytotoxicity
-NK cells have receptors for Fc part of antibodies whose Fab parts are attached to other cells, the NK cells kill the attached cell |
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IgM
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-First Response, Pentamer
-Only class that is produced in response to T-independent antigens -Neutralizes, Immobilizes, Agglutinates, and ADCC (4/6) -Cannot opsonize because it requires a free Fc part and it is already attached to the other antibodies |
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IgG
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-Main serum, longest half-life
-serum because its common in blood serum -can cross the placenta to protect the developing fetus -neutralizes, immobilizes, agglutinates, opsonizes, complement system, and ADCC (6/6) |
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IgA
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-Dimer, main secreted antibody
-mucosal -protects breast fed infants -neutralizes and immobilizes (2/6 ways) |
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IgD
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-Thought to have involvement with memory B cells because many our found in the respiratory system
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IgE
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-contains extra part of Fc regions which mediates binding to mast cell
-Allergic response |
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Serum Antibody
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IgG
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Secreted Antibody
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IgA
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Class Switching
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-cassette switching mechanism
-in response to cytokine signals, the recombinase PTIP is produced and causes differentiation of IgM to IgG or IgA |
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Immune Memory
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-Class switching is important for immune memory because the IgG produced from the first exposure survive and are ready if we are exposed again
-reason why we cannot catch the same cold twice -fight off the second exposure more effectively |
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Somatic Recombination
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-happens during embryonic development
-involves splicing mechanism of DNA -Variable region, Diversity region, and Joining region, we get a particular VDJ combination in the variable region of the antibodies -imprecise joining causes even more variety |
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Somatic Hypermutation
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-mutation rate of dividing B cells is much higher than that of other somatic cells
-increase in variety of B cells |
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Clonal Selection
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-T-dependent activation
-When B cells either pick up a piece of the bacteria floating around or recognize it on an MHC2 of a dendritic cell and engulf the epitope and display it on the B cell MHC2 so it can be recognized by a Th cell -When an activated Th cell recognizes the epitope it causes phosphorylation and releases cytokines which stimulates the B cell to divide and produce clones of itself and become plasma cells to release antibodies and memory cells in which IgG is involved |
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Plasma Cells
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-When B cells are stimulated by Th cells that release cytokines, they become plasma cells and release antibodies (IgM first then IgG or IgA)
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Memory B-cells
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-What B cells turn into when Th cells release cytokines which are important in the second exposure to viruses
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T-dependent antigen
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-Th cells are needed to produce cytokines and stimulate B cells to become plasma and memory cells
-strong immune response response |
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T-Independent Antigen
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-No Th cell to produce memory cells and no Ig class switching
-Weak in comparison to T-dependent antigens -antigen is a repeating antigen which can bind to multiple B cell receptors simultaneously i.e polysaccharide capsule -sensor kinase is triggered, phosphorylate itself and the response regulator turns on genes that produce IgM only |
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Protein-Conjugate Vaccine
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-can turn T-independent antigens into T-Dependent by chemically conjugating a T-independent antigen to a protein which sterically hinders the binding of the antigen so the polysaccharide can only bind to 1 B cell receptor in which a T cell will interact and cause for a strong immune response with memory cells and class switching
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Polysaccharide capsule vaccine
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Weak in comparison to protein conjugate vaccine
-no memory cells or class switching -multiple B cell receptors are binded by the polysaccharide capsule |
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Clonal Deletion
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-immune tolerance
-needed for antibodies that recognize our own cells which can cause autoimmune diseases |
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Negative Selection
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-in bone marrow, if any B cell binds to an antigen they will go through apoptosis
-if for some reason gets our of bone marrow, if it binds to an antigen and does not get activated by a Th cell it will become anergic and eventually die |
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Anergic
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when a B cell is unstimulateable, leads to death of B cells that are self recognizing
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