Immunoglobulins (IgGs) from a variety of sources have been purified using the conventional process composed of a protein A chromatography step along with ion exchange chromatography and hydrophobic interaction chromatography steps (Jiskoot et al. 1989, Godfrey et al. 1993, Shadle et al. 1995, Ford et al. 2001). Protein A chromatography is normally applied as the first step in the process, yielding antibodies with very high purity in a single step. However, the disadvantages of protein A chromatography are: 1) antibody isomers are not well separated from different species; 2) protein A leakage requires additional chromatographic steps for protein A removal; and 3) protein A resins are substantially more expensive than ion exchange and ceramic hydroxyapatite supports.
Here we present an alternative process for antibody purification consisting of UNOsphere S chromatography and CHT ceramic hydroxyapatite chromatography. This process is simpler than the process utilizing protein A and avoids the leakage of a contaminating ligand (Jiskoot et al. 1989).
UNOsphere S support is a strong cation exchanger made from acrylamido and vinylic copolymers. It exhibits high protein binding capacity and low column backpressure at high linear velocity. Thus, it is a suitable capture resin in the downstream purification process. CHT ceramic hydroxyapatite support, with Ca2+ ions and P043- ions in its spherical and ceramic structure, provides excellent resolution and selectivity for protein isolation.