Expert: Ralph Salier-Hellendag - 1/3/2005

Question
sir,
   i have a big confusion. what is the difference between antigens and antibodies?? what do they do?

Answer
Sharmi Nair,

An antigen is any substance that causes your immune system to produce antibodies against it.  The antigen may be a foreign substance from the environment sucha s a chemical, bacteria, virus or pollen, or formed within the body such as bacterial toxins or tissue cells.

An antibody is any one of a large number of proteins of high molecular weight that are produced normally by specialized B cells after stimulation by an antigen and act specifically against the antigen in an immune response.  These antibodies "grab" the antigen and then either destroy the antigen or expell the antigen via one of the normal expulsion routes.