Immunity notes biology B1

Seite 1

http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/keepinghealthy/defendingagainstinfectionrev4.s...

Immunity Pathogens contain certain chemicals that are foreign to the body. These chemicals are called antigens. Certain white blood cells, called lymphocytes, can produce specific antibodies to kill a particular pathogen.

Antibodies Antibodies are proteins. They can neutralise pathogens in a number of ways. For example, they can:

bind to pathogens and damage or destroy them

coat pathogens, clumping them together so that they are easily ingested by white blood cells called phagocytes.

Each lymphocyte produces a specific type of antibody - a protein that has a chemical 'fit' to a certain antigen. When a lymphocyte with the appropriate antibody meets the antigen, the lymphocyte reproduces quickly and makes many copies of the antibody to kill the pathogen.