Multiple immunoblot: A sensitive technique to stain proteins and detect multiple antigens on a single two‐dimensional replica

A multiple immunoblotting technique was developed to positively identify up to three different antigens on a single nitrocellulose replica of a two‐dimensional isoelectric focusing/sodium dodecyl sulfate‐polyacrylamide gel. Three highly sensitive immunoblot assays were selected, including: horseradish peroxidase/luminescence, alkaline phosphatase, and silver‐enhanced immunogold. As a major advantage, the method permits a simultaneous detection of up to three different antigens without eluting the antibody‐dye complex between staining of single polypeptides, thus providing a highly accurate identification of closely migrating components. The staining procedure is summarized in a flow chart. In addition to the multiple immunoblot staining, some suggestions are provided for a sensitive protein staining.