There are several strategies to visualize the antibody. For transmitted light microscopy, color development substrates for enzymes are often used. The antibody can be directly
labeled with the enzyme. However, such a covalent link between an antibody and an enzyme might result in a loss of both enzyme and antibody activity. For these reasons
several multistep staining procedures have been developed, where intermediate link antibodies are used. In this protocol use the Vectastain ABC-kit.