Emd Millipore Corporation

Damon Asher

Ushma Mehta

Matthew T Stone

Patricia Greenhalgh

Anne Leahy

Amanda B Katz

Navid Z Khan

The invention relates to a process for increasing the observed titer of a virus stock for the purpose of increasing the calculated log reduction (LRV) in virus clearance studies. A tissue culture or assay plate is seeded with an indicator cell line and titrated with a virus stock followed, by a centrifugation step for about 5 minutes to about 24 hours at a g-force ranging from about 50&#xd7;g to about 2400&#xd7;g, and at a temperature from about 4&#xb0; C. to about 39&#xb0; C. The resulting calculated virus titer after undergoing the centrifugation step is 10-fold higher than the virus titer would be if determined in the absence of the centrifuging step.

Use of centrifugation-aided infection to increase virus titer

The present invention provides methods for determining whether activated carbon can be used for removing viruses or a certain virus from a sample containing a target protein.

Method of determining virus removal from a sample containing a target protein using activated carbon

The purity and titer of virus stocks used for virus clearance studies have a significant influence on study outcome, and impact how well the scale-down model represents the production-scale process. Impurities in virus stocks are particularly important in the testing of small virus retentive filters because these impurities may cause a filter to foul prematurely, leading to underestimation of the true throughput capability of the filter and consequent inappropriate sizing of the production scale unit. In addition, impurities can also affect the levels of virus clearance observed by altering the fouling mechanisms and subsequent fluid passage through the virus filter. Described herein are methods for making, producing and using high purity virus stocks having high titer.

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Jefferson, MA, United States of America

Damon Asher