EMD Millipore, 6220 Pacific Ave., #103, Playa del Rey, CA 90293, USA.
Biotechnol Prog. 2011 Jan-Feb;27(1):121-8. doi: 10.1002/btpr.500. Epub 2010 Sep 27.
Virus filters are widely used in bioprocessing to reduce the risk of virus contamination in therapeutics. The small pores required to retain viruses are sensitive to plugging by trace contaminants and frequently require inline adsorptive prefiltration. Virus spiking studies are required to demonstrate virus removal capabilities of the virus filter using scale down filters. If prefiltration removes viruses and interferes with the measurement of virus filter LRV, the standard approach is to batch prefilter the protein solution, spike with virus, and then virus filter. For a number of proteins, batch prefiltration leads to increased plugging and significantly lower throughputs than inline prefiltration. A novel inline spiking method was developed to overcome this problem. This method allows the use of inline prefiltration with direct measurement of virus filter removal capabilities. The equipment and its operation are described. The method was tested with three different protein feeds, two different parvovirus filters, two virus injection rates; a salt spike, a bacteriophage spike, and two mammalian virus spikes: MMV and xMuLV. The novel inline method can reliably measure LRV at throughputs representative of the manufacturing process. It is recommended for applications where prefiltration is needed to improve throughput, prefiltration significantly reduces virus titer, and virus filter throughput is significantly reduced using batch vs. inline prefiltration. It can even help for the case where the virus preparation causes premature plugging.
病毒过滤器广泛应用于生物加工过程中,以降低治疗用制品中病毒污染的风险。为了保留病毒而需要的小孔对痕量污染物的堵塞非常敏感,因此经常需要在线使用吸附性预过滤。需要使用缩小规模的过滤器进行病毒加标研究,以证明病毒过滤器的病毒去除能力。如果预过滤去除了病毒并干扰了病毒过滤器 LRV 的测量,则标准方法是分批预过滤蛋白质溶液,用病毒加标,然后再进行病毒过滤。对于许多蛋白质,分批预过滤会导致堵塞增加,并且通过量明显低于在线预过滤。开发了一种新颖的在线加标方法来克服这个问题。该方法允许使用在线预过滤,并直接测量病毒过滤器的去除能力。本文描述了设备及其操作。该方法用三种不同的蛋白质进料、两种不同的细小病毒过滤器、两种病毒注射速率、盐加标、噬菌体加标和两种哺乳动物病毒加标:MMV 和 xMuLV 进行了测试。新型在线方法可以可靠地测量在具有代表性的制造工艺的通过量下的 LRV。推荐在需要提高通过量、预过滤显著降低病毒滴度、以及使用分批预过滤比在线预过滤显著降低病毒过滤器通过量的情况下使用。即使对于病毒制剂导致过早堵塞的情况,它也可能有所帮助。