Preparation and characterization of magnetic microspheres for the purification of interferon α-2b

Magnetic agarose microspheres (MAMS), magnetic cellulose microspheres (MCMS), and magnetic poly(vinyl alcohol) microspheres (MPVAMS) were prepared by various different preparation methods. MCMS coupled with anti-IFN α-2b monoclonal antibodies (mAb) were selected for the purification of interferon α-2b (IFN α-2b) after performance characterization among microspheres. Parameters of immunomagnetic separation (IMS), including binding mAb, elution behavior, and sample pretreatment conditions, were optimized to improve the purification efficiency of the separation of IFN α-2b by MCMS. Size-exclusion HPLC (HPSEC) showed that the IFN α-2b was purified from crude cell lysate had an overall purity of 92.9%, while immunological and biological assays showed an activity recovery of 88.5% and specific antiviral activity of 2.7 × 108 IU/mg. Identity and molecular mass of purified IFN α-2b were confirmed by western blot and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis. This study illustrated the favorable separation media which combined desired properties for the development of magnetic separation of biological materials.