Fetal erythroblast isolation up to purity from cord blood and their culture in vitro

Giammaria Sitar, Silvia Garagna, Maurizio Zuccotti, Cristina Falcinelli, Laura Montanari, Alessandro Alfei, Giovanbattista Ippoliti, Carlo Alberto Redi, Remigio Moratti, Edoardo Ascari, Antonino Forabosco

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Erythroblasts have been the most encouraging candidate cell type for noninvasive prenatal genetic investigation. We previously showed that human erythroblasts can be recovered from bone marrow and blood bank buffy coats by a physical cell separation. In the present study, we modified our previous methodology, taking into account the peculiar behavior of erythroblasts in response to modifications of pH and osmolality of the separation medium. Methods: Twenty to forty milliters of cord blood were initially centrifuged on Ficoll/diatrizoate (1.085 g/ml). The interphase cells were further separated on a continuous density gradient (1.040-1.085 g/ml). Two different gradients were initially compared: the first was iso- osmolar and neutral, whereas the second also contained an ionic strength gradient and a pH gradient (triple gradient). A subsequent monocyte depletion was performed by using magnetic microbeads coated with anti-CD14 monoclonal antibody (mAb), and erythroblasts were purified by sedimentation velocity. Purified cells were investigated by analyses with fluorescence-activated cell sorting (FACS) and fluorescence in situ hybridization (FISH) and immunocytochemistry with mAb against fetal hemoglobin and were cultured in vitro. Results: When nucleated cells were spun on an iso-osmolar and neutral continuous density gradient, two separated bands of nucleated red blood cells (NRBCs) were obtained: a light fraction banding at 1.062 g/ml and an heavy fraction banding at 1.078 g/ml. Conversely, when cells were spun in the triple gradient, NRBCs were shifted to the low-density region. Monocyte depletion by immuno-magnetic microbeads and velocity sedimentation provided a pure erythroblast population. FACS and FISH analyses and immunocytochemistry substantiated the purity of the isolated cell fraction, which was successfully cultured in vitro. Conclusions: We have shown that fetal erythroblasts can be purified up to homogeneity from cord blood, but further refinements of the isolation procedure are necessary before the same results can be obtained from maternal peripheral blood.

Original languageEnglish
Pages (from-to)337-345
Number of pages9
JournalCytometry
Volume35
Issue number4
DOIs
Publication statusPublished - Apr 1 1999

Keywords

  • Cell separation
  • Cord blood
  • Fetal erythroblasts
  • Fetal hemoglobin
  • FISH
  • Flow cytometry
  • Magnetic beads

ASJC Scopus subject areas

  • Hematology
  • Cell Biology
  • Pathology and Forensic Medicine
  • Biophysics
  • Endocrinology

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