OVERVIEW OF THE IMMUNE SYSTEM
LYMPHATIC AND IMMUNE SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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T-cells that bind MHC survive
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T-cells that bind MHC die
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T-cells that bind self antigens survive
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T-cells that bind self antigens die
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T-cells that do NOT bind MHC die
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Detailed explanation-1: -T cells which bind self peptide-MHC with high affinity at this stage undergo negative selection and die by apoptosis.
Detailed explanation-2: -Negative selection (immunology), in which B-cells and T-cells that recognize MHC molecules bound to peptides of self-origin, or just MHC molecules with high affinity are deleted from the repertoire of immune cells.
Detailed explanation-3: -Discrimination of self from nonself antigens and MHC molecules is achieved by negative and positive selection of T cells in the thymus: potentially harmful T cells with receptors that bind to self antigens plus self MHC molecules are deleted before they can mount immune responses.
Detailed explanation-4: -Not all the T-cell receptors generated by gene rearrangement will be able to recognize self MHC molecules and function in self MHC-restricted responses to foreign antigens; those that have this capability are selected for survival by a process of positive selection that occurs in the thymus.
Detailed explanation-5: -Positive selection involves targeting the desired cell population with an antibody specific to a cell surface marker (CD4, CD8, etc.). The targeted cells are then retained for downstream analysis. Negative selection is when several cell types are removed, leaving the cell type of interest untouched.