Friday, 20 April 2012
Isotype Control Antibodies
Isotype controls are most commonly used in flow cytometry experiments for delineating the non-specific background signals caused by the primary antibodies. Isotype control antibodies are designed to retain all the non-specific characteristics of the primary antibodies, except the specificity for target cells in the experiment. The purpose is to confirm the binding of the primary antibody with the target cell is specific and not a result of other non-specific bindings and protein interactions. Thus, isotype controls need to be matched exactly with the primary antibodies to the host species and the isotypes, including heavy chain and light chain. There are many immunoglobulin subclasses available for isotype controls. The isotype control immunoglobulin(Ig) subclasses are IgG1,IgG2a, IgG2b, IgG3 and IgM. Most isotype controls are monoclonal. However, when it comes to more than one IgG subclass, they are not suitable. Therefore, Abnova also offers several isotype control polyclonal antibodies for use inthese circumstances.
Abnova carries conjugated isotype control antibodies, and unlabeled monoclonal antibodies. The conjugation formats and staining conditions are also required to be identical in the experiment in order to accurately assess the level of specific binding. Choosing a conjugated antibody can save you a lot of time and efforts. However, as an alternative, choosing an unlabeled antibody will give you more flexibility for your experiment if you are using more than one dye.