Enrichment for GM-CFU from human bone marrow using Sambucus nigra agglutinin: potential application to bone marrow transplantation.

A new lectin, purified from black elder-berries, Sambucus nigra L. (SNA I, hereafter called SNA), was used for fractionation of normal human marrow cells. The stem cell enrichment capability of SNA was investigated by comparing colony formation (GM-CFU) in unagglutinated cell fractions (SNA-) following agglutination with SNA with that with soybean agglutinin (SBA-). GM-CFU recovery in SNA- was equal or superior to that in the SBA- fraction. A modified procedure was developed to combine stem cell enrichment and depletion of E-rosette-forming T-lymphocytes. Bone marrow cells were exposed in one step to SNA and to untreated sheep red blood cells (SRBC). Nonagglutinated, nonrosetting cells were collected after Ficoll-Hypaque-gradient separation. The procedure, a modification of Reisner's multistep procedure involving the agglutination of SBA+ cells; separation of the unagglutinated SBA- cells from the top of a 5% bovine-serum-albumin gradient; the formation of E-rosettes with SRBC; and the separation of rosettes over a Ficoll-Hypaque gradient, is faster, simpler, and as effective for T-cell depletion and stem cell enrichment.