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28 Cards in this Set
- Front
- Back
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What is the concept of self-tolerance |
Ability of immune system to recognise and not respond against self-produced antigens. Process of self- recognition |
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Significance of self tolerance |
Critical to normal physiological function and overall health. Prevents body attacking own cells that can result in autoimmune disease |
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Determining factors in an immune response? |
Nature of antigens (variation of antigen determines various responses) Maturity of immune system (pre-exposed eg nursery/elderly more suceptible) Route of antigen administration (oral tolerance, nasal, IV triggers different immune response) Dose Persistence (antigens hanging around fro years Vs hours) |
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Which group of antigens do our lymphocytes not respond to under normal circumstances |
Self-antigens |
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Why is a Large repertoire of lymphocyte antigen receptors beneficial |
Antigen receptors matches the vast pool of pathogens |
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Define immune deficiency |
Lack of antigen recognition to certain pathogens |
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How is autoimmune responses prevented |
Tolerance to self antigens |
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Define Tolerance |
•Specific immunological non-reacticity to an antigen •Tolerance to self-antigens and non-self antigens • active immune response, it's antigen specific • has immune memory |
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How is tolerance different from immuno-supression and immunodeficiency? |
These are non- specific and tolerance is antigen specific |
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Define and name immunologically privileged sites in the body |
•Eye/ Brain •These sites do not typically elicit strong immune response often due to a physical barrier eg blood-brain barrier. Limiting the degree that immune cells enter the area •these areas often express higher levels of suppressive cytokines to prevent robust immune responses |
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Name two primary lymphoid organs |
Bone marrow Thymus |
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Name secondary lymphoid organs |
Lymph nodes Spleen Lymphatic vessels |
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Importance of Bone marrow |
Immune regulation occurs here |
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How does the immune system distinguish self from non? |
Central tolerance Peripheral tolerance |
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Define Central Tolerance |
The control checkpoints of immune cell development -non reactive T cell development in thymus -non reactive B cell development in bone marrow |
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Define peripheral tolerance |
The control of immune responses in peripheral organs (spleen, LNs etc) |
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How does central and peripheral tolerance mechanisms deal with self recognition (the outcomes) |
-central- Apoptosis (deletion) Change in receptors (receptors editing in B cells) Development of regulatory T lymphocytes (CD4+T cells only) - Peripheral- Anergy Apologise Suppression |
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Site of action of central tolerance deletion or editing |
Thymus or bone marrow |
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What type of tolerance occurs in peripheral organs (thyroid, pancrease) |
Antigen Segregation |
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What is the mechanism of antigen segregation in tolerance |
Physical barrier to self antigen access to lymphoid system |
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Where does peripheral Anergy take place |
Secondary lymphoid tissue |
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Describe the mechanism of peripheral anergy |
Cellular inactivation by weak signalling without co-stimulation |
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What type of tolerance occurs by suppression of cytokines(intracellular signals) |
Regulatory cell tolerance |
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Where do regulatory cells influence tolerance |
Secondary lymphoid tissue and sites of inflammation |
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Define dcytokine deviation mechanism |
Differentiation to TH2 cells, limiting inflammatory cytokine secretion |
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Where does cytokine deviation take place |
Secondary lymphoid tissue and sites of inflammation |
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What is clonal deletion |
Apoptosis post activation |
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Where does apoptosis post activation in tolerance take place |
secondary lymphoid tissue and sites of inflammation |
