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•  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

antibody actions