About 25 per cent of the white blood cells are lymphocytes. They are part of the body’s immune system and produce soluble proteins called antibodies.
Antibodies attach to antigens. Antigens are substances found on the surface of cells, including bacteria and other pathogens. Different antibodies attach to different antigens. In this way, the body’s immune system can recognise foreign antigens – antigens that are not normally produced by the body, but by pathogens instead.
Antibodies can neutralise toxins produced by pathogens. They can also cause the destruction of pathogens by: