Polyclonals can be used for Western blot, immunohistochemistry on frozen slices or parrafin fixed tissues. The advantage is that there are more epitopes available in a polyclonal antiserum to detect the proteins than in monoclonal sera.Rabbits are used for polyclonal antibody production by Multisciences. Rabbit antibodies are very stable and can be stored for several days at room temperature. Multisciences adds sodium azide and glycerol to enhance the stability of the rabbit polyclonal antibodies. Anti-human, anti mouse antibodies to highly immunogenic selected peptide sequences are" monoclonal like" since the epitope to which they are directed is less than 35 amino acids long.