Secondary antibodies

Secondary antibodies indirectly detect a primary antibody that specifically binds to the protein of interest. They can be conjugated to fluorophores (eg Alexa Fluor® dyes), enzymes (eg HRP, alkaline phosphatase), or proteins (eg biotin) to amplify the signal of primary antibodies.

Secondary antibodies are made by immunizing a host animal with antibodies from a different species. Immunizing a goat with rabbit IgG will generate goat anti-rabbit IgG secondary antibodies. The secondary antibody selected should match the species in which the primary antibody was raised in, as well as the isotype of the primary antibody of interest. For example, a goat anti-rabbit IgG secondary antibody can be used to detect the signal of rabbit IgG primary antibodies.