Baculovirus affinity removal in viral-based bioprocesses

Abstract

The demand for new biopharmaceuticals has grown considerably in the last decade, with their use in applications such as vaccination, gene therapy and oncolytic therapy. However, their biological complexity brings new challenges for up- and downstream processes. Insect-cell based biopharmaceuticals produced using the baculovirus expression vector system (BEVS) have an extra layer of complexity due to the co-production of baculovirus particles. Their rod-shaped form and similar envelope to virus-like particles (VLPs), results in an increasing complexity to strictly discriminate between both particles. This work presents a purification strategy based on an impurity-focused affinity chromatography approach for baculovirus removal from influenza VLPs manufacturing, evaluated as vaccine candidate. Different affinity ligands were discovered by phage display towards baculovirus particles and four ligands were selected with distinct binding profiles. The four ligands (BV-2, BV-3, BV-6, BV-8) were immobilized in chromatographic resins and dynamic binding capacities of 1.64 × 1010, 4.44 × 109, 4.91 × 1010 and 1.15 × 1011 VG/mL were obtained, respectively. The impact of the residence time in the process performance was evaluated and BV-2 and BV-3 ligands showed the best results with baculovirus removals above 70% and VLPs’ recovery yields above 60%. As a proof-of-concept, these ligands were also evaluated using two different biopharmaceuticals produced by BEVS: hepatitis C VLPs and adeno-associated virus (AAV) systems. Finally, these resins proved to be robust to harsh elution and cleaning conditions, maintaining the same baculovirus removal over 20 cycles, being a powerful chromatographic tool for baculovirus removal from biopharmaceuticals produced using BEVS.