Immune response
- Created by: jessicawarren
- Created on: 11-04-16 20:19
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- Immune response
- Antigens
- Proteins on surface of cells that generate an immune response when detected by the body
- Used by immune system to identify pathogens, abnormal body cells, toxins and cells from other individuals of same species
- 1: Phagocytes engulf pathogens
- 1) Phagocyte recognises foreign antigens on pathogen
- 2: Cytoplasm of phagocyte moves around pathogen, engulfing it
- 3: Pathogen now contained in a phagocytic vacuole in cytoplasm of phagocyte
- 4: Lysosome containing lysozymes fuses with phagocytic vacuole. Lysozymes break down pathogen
- 5: Phagocyte presents pathogens antigens to activate other immune system cells
- 2: Phagocytes activate T-cells
- Type of white blood cell. Receptor proteins on surface- bind to complementary antigens with phagocytes
- Activates T-cell.
- Helper t cells release chemical signals that activate/stimulate phagocytes/ cytotoxic t cells which kill abnormal/foreign cells
- Helper t cells also activate b cells which secrete antibodies
- 3: B cells
- Type of white blood cell. covered with antibodies- proteins which bind to antigen to form antigen-antibody complex.
- Each b cell has different shaped antibody, so bind to different shaped antigen
- 1) When antibody on surface of b cell meets complementary antigen, they bind.
- 2) With other substances from helper t cells this activates b cell- clonal selection
- 3) Activated b cell divides into plasma cells
- 4: Plasma cells
- Plasma cells identical to b cells. Secrete antigen specific antibodies- monoclonal antibodies
- Bind to antigens on surface of pathogen to form antigen-antibody complexes
- Antibody has two binding sites- can bind to two pathogens at same time. Pathogens become clumped together- agglutination
- Phagocytes bind to antibodies and phagocytose many pathogens at once.This leads to destruction of pathogens carrying this antigen
- Antigens
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