Successful removal of porcine circovirus-1 from immunoglobulin G formulated in glycine solution using nanofiltration

Porcine circovirus (PCV) is a potentially harmful virus that has been shown to contaminate biological products. The virus is resistant to many inactivation and/or removal procedures performed during manufacturing. Anion exchange chromatography has been shown to be useful for PCV type 1 (PCV1) removal; however, reduction of PCV1 using methods such as heat inactivation, low pH, nanofiltration, UV-C, and gamma irradiation has not been successful. Therefore, in this study, we evaluate various conditions for process solutions during nanofiltration using PCV1. The results indicated that PCV could be effectively removed from glycine solution at 0.1-0.3 M, pH 4.0 without IgG, using a nanofilter with a pore size of 19 nm (19-nm filter); log reduction values (LRVs) of ≥4.5 and ≥ 5.0, respectively, were obtained. In contrast, PCV1 was significantly removed (LRV: 2.2) in glycine solution at 0.3 M, pH 6.0 with 1.0% IgG using the 19-nm filter, but some virus genomes were detected in the filtrates. In summary, the use of a 19-nm filter in glycine solution with/without IgG is an appropriate condition for PCV removal.