difference between monoclonal antibody and polyclonal antibody? - (Mar/06/2013 )

I do not study immunology and am studying it now. After reading the book, I am still confused about the monoclonal antibody and polyclonal antibody. Can anybody give me a simple explanation?

A monoclonal antibody is raised against a specific single epitope of a certain antigen. It is called monoclonal because it is derived from a single clone of identical immune cells which are derived from a unique parent cell. Polyclonal antibody is a mixture of antibodies from different immune cells that are raised against the same antigen, but recognize different epitopes. They are not derived from a single clone of immune cells.

I agree with Tabaluaga's definition. Also, you can think of an antibody as a protein that has a specific amino acid sequence. A monoclonal antibody solution that you purchase should consist only of identical antibodies, all with the exact same amino acid sequence. A single B cell containing just the right DNA sequence was isolated, immortilized, and amplified to give a population of cells that all make precisely that one antibody. Polyclonal antibodies are generally purified directly from serum, so they're the combined efforts of many B cells, each of which might have produced a distinct sequence of amino acids that happens to have affinity for the immunogen.

a polyclonal can be made against a specific epitope.