Highly pure measles virus generated by combination of salt-active nuclease treatment and heparin affinity chromatography

Abstract

Highly purified virus preparations are essential for accurate activity and potency determination. This requires simple and efficient purification methods, especially in the early stages of research and development. While heparin affinity chromatography has been already successfully used for the purification of several enveloped viruses and virus-like particles, we extended its use to purification of very sensitive measles virus. The performance of heparin and heparin-like affinity chromatography was evaluated for the purification of recombinant measles virus, a large and labile enveloped virus used as vaccine or cancer therapy. Since DNA, particularly in the form of chromatin is a critical impurity in enveloped virus preparations, the effect of integration of an endonuclease (Benzonase® or M-SAN) treatment prior to chromatography was also investigated.

Both, Capto™ DeVirS (heparin-like) and Capto™ Heparin were able to capture measles viruses directly from clarified cell culture supernatant. Despite capturing 100 % of infectious measles virus, low recovery (8 %) was observed for Capto™ DeVirS. For Capto™ Heparin recoveries up to 85 % were observed. The combination of M-SAN with Capto™ Heparin enabled the production of highly purified measles virus with a yield of 62 % and a final purity of 10.2 ng dsDNA per dose (1 × 10⁵), outperforming the processes without endonuclease treatment with a yield of 18 %, and a purity of 66.7 ng dsDNA/dose or using Benzonase® with a yield of 38 % and a purity of 21.2 ng dsDNA/dose. As the developed method is simple and scalable it could also be integrated in a downstream process train for measles virus manufacturing.