title: Amplification and purification of T4-like escherichia coli phages for phage therapy: from laboratory to pilot scale.
abstract: We investigated the amplification and purification of phage preparations with respect to titer, contamination level, stability, and technical affordability. Using various production systems (wave bags, stirred-tank reactors, and Erlenmeyer flasks), we obtained peak titers of 10(9) to 10(10) PFU/ml for T4-like coliphages. Phage lysates could be sterilized through 0.22-μm membrane filters without titer loss. Phages concentrated by differential centrifugation were not contaminated with cellular debris or bacterial proteins, as assessed by electron microscopy and mass spectrometry, respectively. Titer losses occurred by high-speed pelleting of phages but could be decreased by sedimentation through a sucrose cushion. Alternative phage concentration methods are prolonged medium-speed centrifugation, strong anion-exchange chromatography, and ultrafiltration, but the latter still allowed elevated lipopolysaccharide contamination. T4-like phages could not be pasteurized but maintained their infectivity titer in the cold chain. In the presence of 10 mM magnesium ions, phages showed no loss of titer over 1 month at 30°C.
authors.affiliation: Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Gilles
authors.initials: G
authors.lastname: Bourdin
authors.forename: Bertrand
authors.initials: B
authors.lastname: Schmitt
authors.forename: Laure
authors.initials: L
authors.lastname: Marvin Guy
authors.forename: Jacques-Edouard
authors.initials: JE
authors.lastname: Germond
authors.forename: Sophie
authors.initials: S
authors.lastname: Zuber
authors.forename: Lise
authors.initials: L
authors.lastname: Michot
authors.forename: Gloria
authors.initials: G
authors.lastname: Reuteler
authors.forename: Harald
authors.initials: H
authors.lastname: Brüssow
mesh_terms: D017122:Bacteriophage T4 / Q000254:growth & development* / Q000302:isolation & purification*; D001691:Biological Therapy / Q000379:methods*; D002498:Centrifugation / Q000379:methods; D004355:Drug Stability; D004356:Drug Storage; D004926:Escherichia coli / Q000821:virology*; D005374:Filtration / Q000379:methods; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D014773:Virology / Q000379:methods