title: Assessment of direct versus indirect magnetic bead-based T-cell isolation procedures followed by magnetic bead-based DNA isolation.
abstract: OBJECTIVE
  To compare direct and indirect bead-based T-cell isolation followed by magnetic bead-based DNA isolation.
  
  
  METHODS
  T-cells were isolated by direct or indirect selection with magnetic bead coated antbiodies followed by magnetic bead-based automated DNA isolation in 10 healthy subjects. Purity of T-cells, purity of DNA (by A260/A280 ratio measurement) and DNA concentration were assessed.
  
  
  RESULTS
  Direct and indirect labelling resulted in comparable T-cell purity (93.11±1.47% vs. 94.99±1.54%, p= 0.125) and DNA concentration per cell (50.97±14.15 ng/(mlxcell) vs. 49.53±13.62 ng/(mlxcell), p=0.492), while DNA purity was significantly higher after direct labelling (1.82±0.05 vs. 1.78±0.03, p=0.0488).
  
  
  CONCLUSIONS
  Both direct and indirect magnetic bead-based T-cell selection may be used prior to magnetic bead-based DNA isolation procedures.
authors.affiliation: Medical Faculty , Hiller Research Center Rheumatology at University Hospital Düsseldorf, Heinrich-Heine-University , Düsseldorf , Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Rosenbaum
authors.affiliation: Medical Faculty , Hiller Research Center Rheumatology at University Hospital Düsseldorf, Heinrich-Heine-University , Düsseldorf , Germany.
authors.forename: Ellen
authors.initials: E
authors.lastname: Bleck
authors.affiliation: Medical Faculty , Hiller Research Center Rheumatology at University Hospital Düsseldorf, Heinrich-Heine-University , Düsseldorf , Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Medical Faculty , Hiller Research Center Rheumatology at University Hospital Düsseldorf, Heinrich-Heine-University , Düsseldorf , Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Pongratz
authors.affiliation: Medical Faculty , Hiller Research Center Rheumatology at University Hospital Düsseldorf, Heinrich-Heine-University , Düsseldorf , Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Vordenbäumen
keywords: DNA isolation; T Cells; epigenetics; magnetic beads