Term
| What is Allelic exclusion? |
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Definition
- Developing B and T cells undergo VDJ rearrangement on only one allele at a time.
- Ensures that each cell will only express one unique antigen receptor
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Term
| Define: Antibody repertoire |
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Definition
- The number of distinct BCR and antibody specificities within an individual.
- Having a diverse repertoire ensures that the ADAPTIVE immune system is capable of responding to a wide array of antigens
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Term
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Definition
- Target of the adaptive immune system
- Originally refers to antibody-generating substance, but also includes peptides that are recognized by T cells
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Term
| Define: Common Lymphoid Progenitor |
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Definition
- Cell type arising from pluripotent stem cells and capable of differentiating into B cells, T cells, and NK cells
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Term
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Definition
- A given T cell will only recognize its antigen when bound to an MHC molecule.
- Examples:
- CD4 T cells recognize peptide antigens presented on MHC class II
- CD8 T cells recognize antigens presented on MHC class I
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Term
| Define: Negative selection |
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Definition
- Developmental process in immature B and T cells that results in apoptosis when the antigen receptor recognizes self antigens
- Important for removing autoreactive lymphocytes from the repertoire
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Term
| Define: Positive selection |
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Definition
- Developmental process in immature B and T cells resulting in the survival of cells that express a functional antigen receptor
- B and T cell precursors that do not express an antigen receptor undergo apoptosis
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Term
| Define: Recombinase Activating Gene (RAG) |
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Definition
- Enzyme required for VDJ recombination
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Term
| Define: Terminal deoxynucleotidyl transferase (TDT) |
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Definition
- Enzyme that randomly incorpates nucleotides between V, D, and J segments during recombination
- TdT contributes to "junctional diversity" of the antigen receptor repertoire
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Term
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Definition
- Non-responsiveness of the immune system to an antigen
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Term
| Define: VDJ recombination |
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Definition
- Process that produces the antigen receptor variable region in developing B and T cells. Antigen receptor genes have several segments:
- Variable
- Diversity
- Junction
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