Think of the immune system as a coat of armor that protects the body from disease caused by bacteria, viruses, parasites, yeast, mold and toxins and helps remove unwanted foreign bodies and cells from our system. For example, when you get a mosquito bite, the red, bumpy itch is a sign of your immune system at work. The flu or a cold is an example of your body failing to stop the germs/bacteria before they get in. Some forms of immunity we are born with while others are developed and while the system never stops it often needs a boost that can be delivered through naturally found things in our diets and by supplements and IV therapy.