VIRAL PARTICLE QUANTIFICATION BY FLOW CYTOMETORY (FCM) AND PRE-PURIFICATION METHODS FOR MEMBRANE CHALLENGE TEST

Abstract

 The applicability of flow cytometry (FCM) for viral particle quantification to membrane challenge testing was examined to identify the performance degradation due to the microstructural changes or microdamage associated with membrane ageing, which is difficult to detect with conventional integrity testing. To evaluate and select a proper purification method for viral particle quantification by FCM, T4 phage purified by ultracentrifugation, medium removal by UF coupled with DNase treatment, medium removal by UF were quantified by FCM, and the effect of purification of host E. coli DNA was evaluated by quantitative PCR. Ultracentrifugation showed a high purification performance, but a viral inactivation was observed. By applying viral particle quantification by FCM with medium removal by UF coupled with DNase treatment to the membrane challenge test, it was revealed that the T4 phage rejection rate (LRV) of the aged membranes was about 2log and was comparable to the rejection rate calculated from the plaque assay method, indicating that the quantification of virus particles by FCM can be applied to the membrane challenge test.