FcRn and the Long Half-Life of IgG Antibodies

A really important component of IgG antibodies is their ability to have a really long half-life in circulation, as opposed to other Ig subclasses. Lower pH causes the IgG antibodies, not the IgM or IgE, but the IgG to bind to FcRn. They then are transported back up to the surface of the cell, and at neutral pH, are released back into circulation.