Immunoblotting and dot immunobinding. Emerging techniques in protein immunochemistry.

Immunoblotting (also known as Western blot) and dot immunobinding (also known as dot blot) immunoassays, used extensively in immunochemical research, have great potential significance for diagnostic testing in the clinical laboratory. Immunoblotting has distinct versatility in immunochemical test applications. Immunoblotting combines the power of gel electrophoresis for resolving the electrophoretic variants of immunologically cross-reacting proteins with the ease and sensitivity of immunodetection on a solid-phase immunoassay. The potential for diagnostic applications includes: assay of antigens from pathologic serum samples, body fluids, and tissue; assay of patient serum samples for antibody against known antigen; and separation and assay of patient immunoglobulin. The usefulness of these applications is enhanced by the possibility of simultaneous use of nonantibody ligand, reversible protein staining, or, in the case of enzyme proteins, the use of substrate to detect activity. Dot immunobinding, in a similar fashion, permits assays of multiple specimens simultaneously on single strips of blotting media using sample sizes as small as 0.1 microL. Also, both immunoblotting and dot immunobinding techniques permit sequential probing of antigens with different antisera, with subsequent elution and recovery of specific antibody probes.