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7 Cards in this Set
- Front
- Back
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How can the production of antibodies against viruses be induced?
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It can be induced by either a natural infection with the virus or by use of a vaccine
-Antibodies can bind and neutralize the viruses and prevent the viruses from infecting host cells |
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How will the virus cause the activation of the immune response?
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Viruses that are present in the lymph fluid or blood will be carried to a lymphoid organ (lymph node or sleepen respectively)
-In lymphoid organ, some of the B cells will have mIg molecules that recognize eptiopes of the surface virus -The virus will bind and cross link the mIg portion of the BCR resulting in a signal casade insitial by Ig alpha/ Ig beta co stimulatory molecules (signal 1 of B cell activation) -VIrus is brought into the B cell in an endosome and processed into peptide fragments that can be displahyed on MHC class II proteins -B cell increases its production of ribosomes and endoplasmic reticulum in prepartion for becoming an antibody factor -This cuases the cell to get much larger and express B7 molecules on its cell surface |
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What are the roles of some of the viruses that are phagocytosed by APCS?
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Some of the viruses phagocytosed by APCs will display antigenic peptides on MHC class II proteins to naive CD4 T helper cells
-After the TCR recognizes the viral petides MHC class II complex, CD3 complex sends a signal to the nuclues (signal 1 of t Cell activation) -CD28 molecule on T cell interacts with B7 Co stimulatory molecle on APC (signal 2 of T cell activation) -Some of the naive CD4 T cells will develop into Th2 type T cells that start to secrete IL-4 which will direct more of the naive CD4 T cells to develop into Th2 type T cells -After the CD28/B7 interaction, the T helper cell will start to express CD40L on its cell surface |
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After the T helper cell has been activated what happens?
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TCR of Th cell binds to viral peptide MHC class II complex on the B cell and the CD28 of the T cell binds to the newly expressed B7 molecule of the B cell
-CD40 molecule on the B cell binds to the CD40L of the TH2 (signal 2 of B cell activation) and the Th2 cell provides the B cell with cytokines resulting in the complete activation of the B cell -IL-4 secreted by the activated Th2 cell causes the activated B cell to divde |
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How many times does the activated Th2 cell and B cell divide?
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They divide many times. Some B cells differentiate into memory cells (important for future responses) and some different into plasma cells
-After 5-7 days, plasma cells secrete antibody into the blood -Antibody circulates throughout the body and neuratlizes the virus thus preventing them rom infecting new host cells |
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What are most viral vaccines based upon?
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They induce the production of antibody that recognizes strucutres on the viruses that are involved in binding to the host cell
-The vaccine allows the person to have a primary response to the virus without getting sick -When the person is exposed to the infectious form of the virus, the memory Th cells and memory B cells mount a secondary response that quickly eliiminates the virus so that the person does not get sick |
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Why is dififcult to design vaccines that activate CTls than vaccines that stimulate antibody production?
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Many drug companes are working hard to create vaccines that activate CTLS
-Think about why this is harder |
