Secondary Antibody Function & Applications
Secondary antibodies bind to primary antibodies (on the Fc region) or fragments of antibodies (Fc or Fab), enabling indirect detection and purification of an antigen. They are essential for immunolabeling in ELISA, Western Blotting, Cellular Imaging and Flow Cytometry.
Targeting Primary Antibodies
These antibodies can target primary antibodies from a particular species, such as rat, known as anti-rat antibodies, allowing one secondary antibody to target multiple primary antibodies. On top of that, they can be specific to a particular class of antibodies such as IgG, or even IgG1.
Some secondary antibodies can amplify the signal via conjugated fluorescent, colorimetric or chemiluminescent probes. Colorimetric assays detect alkaline phosphatase or horseradish peroxidase conjugates, and the streptavidin conjugate binding system enhances the colorimetric signal. Fluorescent assays detect Fluorescein (FITC), Rhodamine, TRITC, Cyanine (Cy3) or Phycoerythrin (R-PE).