Mesenchymal stem cells (MSCs) are capable of down-regulating alloimmune responses and promoting the engraftment of hematopoietic stem cells. MSCs may therefore be suitable for improving donor-specific tolerance induction in solid-organ transplantation. Cells from cadaveric vertebral bone marrow (V-BM), aspirated iliac crest-BM, and peripheral blood progenitor cells were compared. Cells were characterized by flow cytometry and colony assays. MSCs generated from V-BM were assayed for differentiation capacity and immunomodulatory function. A median 5.7 x 10(8) nucleated cells (NCs) were recovered per vertebral body. The mesenchymal progenitor, colony-forming unit-fibroblast, frequency in V-BM (11.6/10(5) NC, range: 6.0-20.0) was considerably higher than in iliac crest-BM (1.4/10(5) NC, range: 0.4-2.6) and peripheral blood progenitor cells (not detectable). MSC generated from V-BM had the typical MSC phenotype (CD105(pos)CD73(pos)CD45(neg)CD34(neg)), displayed multilineage differentiation potential, and suppressed alloreactivity in mixed lymphocyte reactions. V-BM may be an excellent source for MSC cotransplantation approaches.