What does Isotype Control do? How to choose a suitable isotype control antibody?

Isotype control antibodies are used as the basis for determining negative and positive cells. It is necessart as a gating helper especially for the indicators with low expression or continuous expression. The Isotype control was purified from the serum of non-immunized animals, it should be the same species source, same immunoglobulin and subtype, same fluorescein label, same dose and concentration as the stained monoclonal antibody.