And the antigen binding side contains a specific sequence of amino acids that has a high affinity for that antigen. Now, if these are the antigens, the antigens also contain a sequence of amino acids that basically bind to that antigen binding side of the antibody. So every antigen contains an epitope, which is a specific sequence of amino acids that binds onto the antigen binding side of that immunoglobulin of that antibody. Now, once that binding process takes place, we form the antibody antigen complex. Now what takes place next? Well, once this binding process takes place it elicits a series of different responses by our immune system.