Polygard cr opticap xl capsule

The MV-containing supernatant was harvested from the reactor by passing the broth through a 5-µm Polygard CR Opticap XL-Capsule (Merck Millipore, Burlington, Massachusetts, USA) to remove microcarriers, cells, and cell debris, and was stored at −80 °C. Before TFF experiments, MV suspensions were centrifuged for 10 min at 300× g using a Heraeus Multifuge X1R (Thermo Fisher Scientific) or clarified by depth filtration/microfiltration (Figure 1a). The clarified suspensions were pooled before transfer to the TFF system (Figure 1b).

The MV strain MVvac2 GFP (P) was propagated in Vero cells (#CCL-81, ATCC), as previously described [12 (link)]. MVvac2 GFP (P) is an infectious recombinant vaccine strain, kindly provided by Dr. Michael Muehlebach (Paul-Ehrlich-Institute, Langen, Germany). MV suspensions were produced by dynamic fermentation in a stirred-tank reactor [12 (link)]. Briefly, the Vero cells were grown on Cytodex 1 carriers (3 g L⁻¹) (GE Healthcare, Little Chalfont, UK) either in serum-containing medium (DMEM-HG supplemented with 10% (v/v) fetal calf serum, both from Biochrom, Cambridge, UK, and 10 mM HEPES) or serum-free medium (VP-SFM, ThermoFisher Scientific, Waltham, MA, USA) [12 (link)]. At the end of fermentation, the MV-containing supernatant was harvested by passing through a 5 µm Polygard CR Opticap XL-Capsule (Merck Millipore, Darmstadt, Germany) to remove carriers, cells, and cell debris. The supernatant was then centrifuged for 10 min at 300 g in a Heraeus Multifuge X1R (Thermo Fisher Scientific, Waltham, MA, USA). The MV titer was established by measuring the infectivity of the virus using the 50% tissue culture infective dose (TCID₅₀) method [11 (link)] and converting this to a titer, as previously described [23 (link),24 (link)].