Purification of Immunoglobulin G

IgG can be purified, as described here, by ammonium sulfate precipitation followed by size-exclusion (SE) chromatography. This is the least expensive option available for purification of antibodies. Protein A- and protein G-affinity chromatography are the fastest methods for purifying antibodies, but they are not effective for all subclasses of rat antibody. A protocol for affinity chromatography using anti-rat antibody is provided for purification of rat antibodies. Ion-exchange (IEX) chromatography is described for purifying intact monoclonal and polyclonal antibodies and antibody fragments.