The Specific Immune system
Antibodies:
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Key Terms:
Antigen: Identifying chemical on the pathogen surface which stimulates an immune response.
Antibody: Y-shaped glycoprotein produced by B lymphocytes in response to an antigen.
Opsonin: A substance which 'tags' pathogens for phagocytes.
Agglutin: A substance which clumps pathogens together, so phagocytes can easily ingest multiple pathogens.
Cells in the Immune Response:
- T Helper Cells: Bind to the surface antigens on APCs which produce interleukins (cell signalling molecules) to stimulate the production of other T + B lymphocytes, and attract phagocytes.
- T Killer Cells: Destroys pathogens, in cell mediates immunity, by producing perforin to break down pathogen cell walls.
- T Memory Cells: Part of the immunological memory. If they meet an antigen a second time, they rapidly divide to form lots of T Killer Cells.
- T Regulator Cells: Stop immune responses once pathogen has been eliminated, and ensure there is no immune response against self-cells.
- B Plasma Cells: Produce and release antibodies.
- B Effector Cells: divide to form B plasma cell clones.
- B Memory Cells: Part of the immunological memory. Remembers a specific antibody and then rapidly produces that antibody upon a second infection.
Cell Mediated Immunity:
Humoural (Cell Non-Mediated/Antibody Mediated) Immunity:
Key Terms
Clonal Selection: Where B effector cells with antibodies complementary to the pathogen's antigens are selected for division.
Clonal Expansion: Where B effector cells rapidly divide into B plasma and B memory cells.
Primary Immunity: Where antibodies produced by plasma cells inhibit the pathogen.
Secondary Immunity: Where antibodies produced by memory cells inhibit the pathogen upon second infection.
Autoimmune Diseases:
- An autoimmune disease is a condition in which the immune system attacks healthy body tissue, as it fails to recognise self-cells.
- e.g.Type 1 diabetes, rheumatoid arthritis and lupus.
- Immunosupressant drugs can be used to treat autoimmune diseases, but they also deprive the body of its natural defences against pathogens, as the immune system is stopped working.