the immune system

• foreign antigens trigger an immune response
• antigens are usually proteins that generate an immune response when detected by the body
• antigens are usually found on: pathogens, abnormal body cells, toxins, cells from other individuals of the same species
• four main stages of the immune response:

  1. phagocytes engulf pathogens
  2. phagocytes activate T-cells
  3. T-cells activate B-cells, which divide into plasma cells
  4. plasma cells make antibodies to a specific antigen
• cellular immune response - the T-cells and other immune system cells they interact with, ie. phagocytes
• humoral immune response - B-cells, clonal selection, and the production of monoclonal antibodies