|MadSci Network: Immunology|
The white blood cells can eat microorganisms and digest them. The two main types of phagocytes (“eating cells”) in your blood are neutrophils and monocytes. These cells can also leave the bloodstream and get into the tissue if you have an infection, say from a cut on your finger. Phagocytes especially like to eat bacteria that have been coated with antibody and with another blood protein called complement. Vaccination against microorganisms leads to the production of these antibodies. The bacteria are then taken inside the phagocytes, which are specialists in killing them. The intracellular compartment where the ingested bacteria are located is flooded with proteolytic (“protein breaking”) and other enzymes which digest the bacterial proteins and cell walls. Another series of enzymes are activated and they produce substances which are very toxic to the microorganisms including hydrogen peroxide and hypochlorous acid (the active component of household bleach). Most microorganisms are killed by this powerful combination of enzymes and chemicals, but a few such as Mycobacteria, which cause tuberculosis and leprosy, are resistant. You can see a movie of phagocytosis at: http://www.cellsalive.com/mac.htm< /a>
Try the links in the MadSci Library for more information on Immunology.