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Abstract:
Introduction. Influenza disease caused by influenza virus impacts every year up to 10% of the world’s population. Vaccination with attenuated or inactivated virus is the principal means of prophylaxis. One approach for the purification of influenza virus is separation based on size using size-exclusion chromatography (SEC). However, SEC often suffers from low productivity posing a bottleneck in downstream processes. Here we present an elegant approach for maximizing the productivity in SEC on the example of vaccine production from cell-culture derived influenza virus.
Method. Based on experimental data, a simple method was developed for the prediction of purity, yield and dilution as a function of column load and fractionation. Virus-containing cell culture supernatant (concentrated by cross-flow ultrafiltration) was loaded onto an SEC column at various pulse lengths. Chromatograms were obtained by offline analysis of eluate fractions (HA activity, total protein). Numerical deconvolution of spline interpolated chromatograms followed by least-squares optimzation resulted in the Dirac response of the system. The response to arbitrary loading functions was predicted by convolution with this Dirac response. Predictions of the method were validated by comparison with a control group.
Results and Conclusions. Applying the method to a previously established SEC operation, productivity was tuned to 0.15 cv h-1 (at a constant flow rate of 60 cm h-1) while dilution was limited to 0.5 (process requirements were the 95% recovery of eluting virus and a 33% reduction in total protein content). In combination with cross-flow ultrafiltration 20-fold reduction in total protein was achieved. Currently, the method is being extended to incorporate the effects of the flow rate and column length. The method is by no means limited to SEC of influenza virus but provides a general tool aiming at the reduction of experimental work. Due to the nature of the approach no a priori knowledge of the feed composition is required.
