Labels for Antibodies

Abstract

For years, microscopists have wanted specific stains or labels for different types of cells and different parts of cells. Prior to the mid-1900 s, only dyes were available, many of which stained special categories of compounds. Examples of dyes are hematoxylin that labels nuclei blue and eosin that labels cytoplasmic proteins pink. However, these did not allow labeling of unique proteins or compounds. The first demonstration of a method to label specific proteins came in 1942, when Albert Coons and his colleagues introduced antibody labeling of bacteria within infected human cells (Coons et al., 1942). Coons et al. used an antibody labeled with a fluorescence compound. For the first time, label conjugated to antibodies was used to specifically localize molecules in a microscope. This was the beginning of immunocytochemistry. Today, the strategies for labeling antibodies have continued to evolve and now, many labeling options are available.