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7 Cards in this Set
- Front
- Back
Explain the difference between direct and indirectallorecognition regarding tissue transplantation |
Direct Donor DCs activate T cells alloreactive CTLs Indirect graft cells ingested by host DCs MHC present to T alloreactive T cells |
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what are the different types of graft rejections and what is involved in each type? |
1 - HYPER ACUTE within minutes, thrombus developed in graft vessels leading to ichaemia mediated by circulating Abs specific for graft endothelial cells 2 - ACUTE days/weeks, T (CD4/8 Allo) and Ab mediated response specific for graft Classical complement pathway 3 - Chronic months/years later, fibrosis of graft (narrowing BVs) T cells reacting against allo Ag ->cytokines -> fibroblasts |
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What are immune responses to tumours? |
Tumour cell recognised by mutated self protiens, products of oncogenes/mutated suppressor genes, over expressed self protiens, products of onconic virus DC phagocytoses tumour Ag activates Ag specific CD8+ CTL in lymph node Migration of CTL to tumour CTL kills tumour cell |
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What are some tumour evasion mechanisms from the immune response? |
Failure to produce tumour Ag Mutations in MHC genes needed for Ag processing Production of immunosuppressive protiens (TGF Beta) and inhibitory cell surface receptors (ligands, PD1) |
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what are some strategies for enhancing antitumour responses? |
1. passive immunity transfer tumour specific T cells or Ab into patient in combination with chemotherapy (take T cells/Ab, prolif, put back) 2. Checkpoint blockade: active immunity enhanced by blockade of inhib molecules -vaccination of tumour Ag (take DCs, show cancer in culture, put polyclonal DCs back) -block cancer inhib signals for lymphocytes (PD1 + CTLA4 for melanoma FDA approved!) |
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How does someone typically develop an autoimmune disorder? |
inheritance of susceptibility genes + environmental triggers |
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What are the mechanisms of microbes that can lead to autoimmunity? |
1.infection -> innate response -> increase in cytokines and costim from APC -> APC stimulate self reactive T cell -> autoimmunity 2. Peptide Ag are similar to (or can cross react with) self Ag 3. innate immune response alters structure of self Ag (eg rheumatoid arthritis) acute and chronic response to bacteria causes enzymatic conversion in self protiens, recognised as non self (also infection may lead to exposure of self Ag that are usually sequested from immune system (eg eye/testes trauma leading to exposure)) |