Optimization of sulfated cellulose membrane adsorbers for the purification of influenza virus

The impact of influenza virus worldwide drives significant efforts and resources into R&D of vaccine manufacturing processes. A major challenge is to improve the flexibility of these processes, without substantially compromising productivity. As in other biotechnological processes, implementation of a chromatographic capturing step is favored since it removes the majority of the impurities (host cell proteins and DNA) and concentrates the product before polishing. Over the last years, significant efforts towards the development of sulfated membrane adsorbers were made. An improved membrane structure and the direct sulfation of a cellulose matrix resulted in a membrane adsorber (SCMA) with pseudo-affinity characteristics which can be used in the main chromatographic separation step for influenza virus. Pore size and ligand density are structural characteristics critical for the performance of the SCMA. For the best combination tested, the dynamic binding capacity (DBC) of the SCMA was shown to be 5.6×106 HAU/mlmembrane, which corresponds to an approximately 5.5 times higher capacity than bead-based media. However, both SCMA and bead-based media show a similar performance in terms of product recovery (86%-96%) and contaminant removal. Experimental results revealed the importance of operational parameters like virus concentration, flow rate, conductivity and elution salt concentration. Therefore, a DoE was used to determine the optimal process conditions in terms of product losses in the flow through as well as overall product yield and purity for an optimized SCMA using an influenza H1N1 virus strain. Currently undergoing experiments aim the identification of the best operating conditions, reevaluation of the DBC and purification performance of the optimized SCMA for the same virus strain. The robustness of the process for other virus (e.g. influenza H3N2 and B) is also being considered. Combining the advantages of a membrane chromatographic support with a chemical modification that is shown to be specific for the purification of influenza virus is a significant technological advance. After optimization of the SCMA and the respective operating conditions significant improvements in the influenza vaccine production process are to be expected