Antibodies of IgG isotype(s) are the most commonly used antibodies in research, diagnostics and therapy. Upon hearing the word antibody most of us will instantly think of those Y-shaped depictions of antibody-proteins that are meant to reflect the shape of IgG.
Antibody formats however don’t stop there. “Man-made” antibody fragments such as Fab and Fab2 are derivatives of antibodies with a multitude of advantages and applications in research, diagnostics and therapy (you can find more information on these in our assay development section). Yet nature offers a range of other formats, with unique characteristics as discussed in our Antibody Resource section, which our recombinant antibody technology allows researchers to explore.
IgM, A, E, D
In brief, IgM, the predominant antibody in the primary immune response, can present as a pentamer or hexamer in solution and as a monomer on the surface of B-cells.
IgA, which can be found in a monomeric or dimeric form, is the predominant antibody in mucous secretions such as saliva, tears, milk and intestinal juice. It is also involved in preventing opportunistic pathogens from entering through mucosal barriers.
IgE has two additional constant domains in place of the hinge region and whilst playing an important role in defence against parasites, also is a key mediator of Type I hypersensitivity reactions or allergies.
Finally, IgD, found predominantly on the surface of B-cells, and is thought to be involved in transduction of activating signals, albeit other functions of IgD may yet be discovered. It has similar structure as IgG, but with an extended hinge region which is very susceptible to proteolytic digestion.