An immunoglobulin-enzyme bridge method for localizing tissue antigens

An immunohistochemical method not requiring conjugation of a label to antibody is described for visualizing tissue antigens. The method depends on binding of an enzyme label to the tissue antigen through the antigen-antibody reactions of an immunoglobulin-enzyme bridge. This bridge is composed of the following components in order: (a) specific antiserum to the tissue antigen, (b) antiserum against the Immune globulin of the species for component a, (c) specific antiserum prepared against the enzyme label in the same species as component a and (d) enzyme label. The bridge method employing horseradish perozidase as the enzyme label has been applied to localization of cells forming growth hormone and chorionic gonadotrophin in the human adenohypophysis and placenta re-sectively. Several sensitive iminunohistochemical meth-ods have been developed for the localization of tissue antigens. These methods involve the chemical conjugation of demonstrable labels to specific immunoglobulins which can then be use