What are antibodies?
Secondary antibodies or a secondary antibody is an antibody that is used to bind to the immunoglobulin (IgG) domain of the primary antibody. The secondary antibody will be specific to the species and isotype of the primary antibody, in applications such as immunoblotting or immunocytochemistry. Several antibodies can bind to the same primary antibody, which increases sensitivity and amplifies the signal.
Antibodies are usually conjugated to indicator molecules, enzymes such as HRP, or fluorophores such as APC, to allow detection of the primary antibodies by fluorescence, colorimetry or chemiluminescence. Advantages of secondary antibodies They are used for indirect detection of a target to which a specific primary antibody binds first.
Secondary antibody must be specific for both the antibody species and the isotype of the primary antibody used. In addition, a secondary antibody usually has a detectable label or other marker that facilitates detection or purification. Indirect detection of the target antigen using proteins requires more steps than direct detection using primary antibodies.
Antibodies with specificity for primary antibodies of common species are commercially available, pre-configured with a wide range of common markers, including enzyme and fluorescent conjugation options.
What are the best secondary antibodies?
Most primary antibodies are produced in mice or rabbits; therefore, anti-mouse IgG and anti-rabbit IgG are the most popular types of proteins. The goat is the most readily and frequently used host species by manufacturers to produce polyclonal anti-mouse and anti-rabbit secondary antibodies.
What are secondary antibodies used for?
Secondary antibodies assist in the detection, selection and purification of target antigens. To enable detection, the secondary antibody must have specificity for the antibody species and isotype of the primary antibody used and is usually conjugated.
Antibodies are proteins produced by the body’s immune system when it detects harmful substances, called antigens. Antigens include micro-organisms (such as bacteria, fungi, parasites and viruses) and chemicals.
Learn more about antibodies.