Enrichment of myeloid progenitor cells from normal human bone marrow using an immune-rosette technique.

In this study we have developed methods for purification of myeloid progenitor cells (CFU-Cs) from normal human bone marrow cells. Bone marrow aspirates were obtained from volunteers, and mononuclear cells (MNCs) were separated by Ficoll-Hypaque gradient centrifugation. T- and B-lymphocytes, monocytes, mature granulocytes, and erythroid precursors were eliminated by an immune-rosette technique using a panel of murine monoclonal antibodies and immunoglobulin (Ig)-coated sheep red blood cells (SRBCs). MNCs were treated with OKT3, B1, M3, Mo5, and EP1 monoclonal antibodies, which are reactive with T cells, B cells, monocytes, granulocytes, and erythroid precursors, respectively. Antibody-treated MNCs were incubated with SRBCs that had been coated with goat antirabbit IgG F(ab')2 and rabbit antimouse Ig for immune rosetting. Rosetted cells were then separated from nonrosetted cells in Ficoll-Hypaque. Nonrosetted cells were, in the second step, treated with an OKIa1 monoclonal antibody and again separated into an Ia+ and Ia- cell fraction by the same manner; 39% +/- 19.2% (mean +/- 1 SD, range 16.3%-75.4%) of CFU-Cs (colonies plus clusters) were recovered in the OKT3-, B1-, M3-, Mo5-, EP1- cell fraction, and the number of CFU-Cs grown in semisolid agar was 149.6 +/- 73.0 (64.0-309.0)/10(4) plated cells in this purified fraction, representing an enrichment of 14.2 +/- 6.4 (6.0-27.3)-fold when compared with unseparated marrow cell fractions. CFU-Cs were enriched 17.7 +/- 8.6 (6.1-28.3)-fold in the Ia+ cell fraction. These purified myeloid precursors would be of value for in-depth studies of the interactions between hematopoietic progenitor cells and regulatory factors that influence their proliferation and differentiation and also of drug metabolism and determinants of cytotoxicity.