Western Blot

Excerpt

The term western blot was first coined by Dr. Burnette in 1981 after the eponymous Southern blot for DNA and the consequent coinage of the northern blot for RNA in 1977. Western blotting separates, detects, and identifies one or more proteins in a complex mixture. This process involves separating the individual proteins by polyacrylamide gel electrophoresis and then transferring or blotting onto an overlying strip of nitrocellulose or nylon membrane by electro-blotting. Once the proteins are in the membrane, they can be detected using antibodies labeled with probes, such as radioactive isotopes or enzymes. When such probes are used, the detection limits can be 10 to 100 times lower compared to those achieved through direct immunoprecipitation and protein staining methods. Densitometric analysis of the bands on a Western blot enables researchers to quantitatively compare samples, such as evaluating the effects of treatments or time points.

Centers for Disease Control and Prevention no longer recommends the western blot test as a diagnostic tool. This article remains for historical purposes and supports laboratories that still use the technique. However, it is no longer being actively updated.