11.2 - Actions of Antibodies

Antigen-Antibody Interactions

Antibodies destroy antigens through five mechanisms:

Neutralisation

• Antibodies bind with toxins produced by bacteria and neutralise the toxins.

Agglutination

• Antibodies coagulate pathogens, making them easy targets for phagocytes to trap and destroy.

Precipitation

• Antibodies react with dissolved antigens to form an insoluble complex, or precipitate, that phagocytes destroy easily.

Opsonisation

• Antibodies combine with antigens and act as markers so phagocytes can recognise and destroy the antigens.

Lysis

• Antibodies combine with antigens and cause bacteria to break down and decompose.