Purification and concentration of model viruses using single-pass tangential flow filtration

The vaccine and viral vector industry is growing at an accelerated rate. To improve harvest and purification processes, the development of continuous membrane-based operations, such as normal flow filtration (NFF) and single pass tangential flow filtration (SPTFF) for concentration were explored. This work was conducted using two model viruses, non-enveloped porcine parvovirus (PPV) and enveloped Suid herpesvirus (SuHV). The viruses are in the same family as the gene therapy vectors adeno associated virus and herpes simplex virus, respectively. SPTFF design started with batch TFF for membrane selection. Hollow fiber membranes with a 100 and 300 kDa molecular weight cut off were defined for PPV and SuHV SPTFF operations, respectively. The SPTFF runs for PPV did not provide any concentration of the virus and low protein and DNA removal, unlike batch TFF. Two hollow fiber membranes run at 10 mL/min and 2 psi were the best condition for SuHV concentration, with approximately 100-fold titer concentration and protein and DNA removal of 37% ± 5% and 32% ± 8%, respectively. This concentration was superior to the batch TFF and indicated a strong dependence on flow rate and transmembrane pressure. For NFF, filters selection and performance tests were carried out for NFF of PPV and SuHV, as well as cleaning protocols for hollow fiber membranes. The ultimate goal is to integrate this work into the continuous purification of viral vectors produced in mammalian cell cultures to reduce costs and increase throughput.