Mustang q xt5

The load material for all experiments used a sample of an IgG₁ mAb of concentration 7.9 mg/mL with pI of 8.9–9.1 in approximately 76 mM phosphate buffer, 25 mM sodium chloride containing 1.43 pg DNA/mg mAb and over 95% monomer by high performance size exclusion chromatography. The HCP stock solution was obtained from null CHO cells generated from a cell line that was grown under similar conditions to the mAb producing cells. All reagents for buffers were purchased from J.T. Baker, PA.
The AEX chromatography media studied were the resin Toyopearl SuperQ‐650M, referred to as SuperQ (Tosoh Bioscience LLC, PA), and the membranes Mustang® Q XT5 (Pall Corporation, NY) and Sartobind® Q Pico (Sartorius Stedim Biotech, NY), referred to as Mustang Q and Sartobind Q, respectively. The SuperQ column was packed at a compression of 1.2 to a 19.6 cm bed height × 0.66 cm bed diameter (6.7 mL column volume). The Mustang Q XT5 used a capsule with membrane volume of 5 mL and Sartobind Q Pico used a capsule with a membrane volume of 0.08 mL.

Supernatants collected from an iCELLis on days 3–6 post-induction were filtered through an Opticap XL2 capsule Durapore 0.45-μm filter (EMD Millipore, Darmstadt, Germany) and pooled together into a 5-L Flexboy bag (Sartorius, Goettingen, Germany). The concentration of NaCl in the sample was increased by 250 mM with the addition of AccuGene 5 M NaCl (Lonza, Basel, Switzerland). The pH of the sample was adjusted with 1 M Tris (pH 8.0) to a final concentration of 50 mM Tris (pH 8.0).
After NaCl and pH adjustment, the sample was loaded on a Mustang Q XT5 (Pall Corporation) at 50 mL/min and equilibrated with 400 mM NaCl and 50 mM Tris (pH 8.0). Lentivirus was eluted from the column using 1.5 M NaCl/50 mM Tris (pH 8.0) in 15 mL. Eluted fractions were diluted 5-fold into 6.6 mM phosphate buffer (pH 7.4). The diluted fraction was concentrated and diafiltrated into X-VIVO 10 (Lonza) by tangential-flow filtration at 50 mL/min using a 0.005-m² Pellicon XL ultrafiltration module with a 500-kDa cutoff (EMD Millipore, USA). No pressure gauges were used, and the retentate line remained fully open. Purified supernatant was filtered through a 0.22-μm polyvinylidene fluoride (PVDF) Millex syringe filter (Millipore).