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7 Cards in this Set
- Front
- Back
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Elimination of foreign antigen 3 steps |
1. Recognition of foreign antigens. 2. Activation of immune cells. 3. Production of effector cells |
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Cellular Co-operation 3 stages |
1. Antigen presentation and processing 2. T cell activation 3. B cell activation |
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3 types of APCs |
Macrophages - phagocytose antigen B cell - if activated, receptors bind to antigen and engulf via receptor mediated endocytosis Dendritic Cell - express MHC class II, engulf via pinocytosis, move to spleen or lymph node |
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Antigen presentation and processing procedure |
1. Cell engulfs organism, phagosome formed 2. Phagosome fuses with lysosome 3. Lysosomal enzyme breaks down organism into peptide fragments 4. MHC class II molecule-containing-vesicle fuses with lysosome. 5. Peptide fragments bind to grooves of MHC II molecules. 6. Vesicle moves to cell membrane, contents exocytosed. 7. MHC II with fragments presented on cell. |
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T cell activation |
1. Specific T cell receptors recognise antigen on MHC II, CD4 binds to it. 2. T cell activated, produces cytokines. 3. Cytokines released, stimulate other immune cells. |
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B cell sensitisation |
Each B cell carries antibody molecules on membrane. If antigens bind, B cell is sensitised. Encounters a helper T cell already activated. Helper T binds to MHC complex and releases chemicals like cytokines. B cell divides. Plasma cells make antibodies. |
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4 groups of cytokines |
1. Chemokines - cell migration, attract phagocytes and lymphocytes. 2. Haemopoietins - stimulate RBC growth and differentiation. 3. Interleukins - regulate growth and differentiation of laukocytes 4. Tumour Necrosis Factor - Cytotoxic to tumour cells, promote fever. |
