Understanding:
• Plasma cells secrete antibodies
• Antibodies aid in the destruction of pathogens
When a specific B lymphocyte is activated following antigen presentation, it divides into plasma cells and memory cells
- Plasma cells are short-lived and secrete high numbers of antibodies that are specific to a particular antigen
- Plasma cells will secrete ~ 2,000 antibody molecules per second into the bloodstream for roughly 4 to 5 days
Antibodies aid in the destruction of pathogens by a number of different mechanisms:
• Precipitation – Soluble pathogens become insoluble and precipitate
• Agglutination – Cellular pathogens become clumped for easier removal
• Neutralisation – Antibodies may occlude pathogenic regions (e.g. exotoxins)
• Inflammation – Antibodies may trigger an inflammatory response within the body
• Complement activation – Complement proteins perforate membranes (cell lysis)
Mnemonic: PANIC
Collectively, the action of antibodies enhance the immune system by aiding the detection and removal of pathogens by the phagocytic leukocytes of the innate immune system (macrophages)
- The constant region of antibodies can be recognised by macrophages, improving pathogen identification (opsonisation)
- The macrophages can now engulf and eliminate pathogens more efficiently, reducing disease symptoms
Antibody Actions
