The Application of Dextran Sedimentation as an Initial Step in Neutrophil Purification Promotes Their Stimulation, due to the Presence of Monocytes

Figure 1

The application of dextran sedimentation prior to Ficoll-Hypaque density gradient centrifugation modulates adhesion receptor expression of neutrophils. Blood for each individual was applied to the 2-step methods, with dextran sedimentation (DS) preceding (1st) or following (2nd) Ficoll-Hypaque density gradient centrifugation, and the 1-step high-density Ficoll-Hypaque gradient centrifugation. The neutrophils were analysed for CD18, CD11b, and CD62L surface expression by flow cytometry. (a) Representative fluorescence intensity histograms of each surface neutrophil adhesion receptor molecule and respective isotype controls for purified neutrophils from each 2-step method for an individual blood sample. The histograms of unfractionated whole blood from the same sample are included for reference. (b) Relative CD18, CD11b, and CD62L surface expression between neutrophils purified by each 2-step method normalised to expression observed by neutrophils of the 1-step method (). (c) Relative CD11b and CD62L surface expression between neutrophils purified by different concentrations of dextran for sedimentation prior to low-density Ficoll-Hypaque gradient centrifugation normalised to expression observed by neutrophils of the 1-step method (). Statistical comparisons were made against a final concentration of 2% dextran. (d) Relative CD11b and CD62L surface expression between neutrophils purified by dextran sedimentation prior to low-density Ficoll-Hypaque or Percoll gradient centrifugation, normalised to expression observed by neutrophils of the 1-step method ().

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