Large scale use of Spherosil ion exchangers in plasma fractionation

Spherosil microbeads are spherical and made of porous silica. Their surface is coated with hydrophilic and/or hydrophobic polymers. They are specially designed for the separation of proteins on an industrial scale either by ion exchange or by bioaffinity chromatography. Since 1980, large columns have been used in Institut Mérieux for the purification of placental albumin and several vaccines. Here we describe a chromatographic process for the purification of human albumin and immunoglobulins (IgG) from 25 1 of plasma per cycle. First the plasma was freed of the coagulation factors and then clarified at pH 5.25. The corresponding supernatant was filtered and processed in sterile conditions. Albumin was then purified by ion exchange on 3 successive columns, respectively containing: 6.25 kg of DEAE SPHEROSIL W-1000; 3.5 kg of QMA SPHEROSIL PH-1000; 8 kg of COOH-SPHEROSIL W-1000. The concentration and pH of the buffers were selected to reduce, as much as possible, the total quantity of ion exchangers required per cycle. IgG were then purified from the filtrate of the first of the previous columns. 1 column of 6.25 kg of DEAE SPHEROSIL W-1000 was used at pH 6.8. The selected chromatographic parameters allowed us to demonstrate a total elimination of HBs Ag and HB Virus when voluntarily added to an initial sample (RIA determination and HBV-DNA analysis by molecular hybridization). A second column of a large pore anion exchanger: DEAE SPHEROSIL LP-3000 was added at the end of the IgG purification, as a final security to avoid any risk of transmitting the Hepatitis B virus. The yield and quality of the final products will be presented.