Sea-1 lin cells capable of providing long-term engraftment in lethally irradiated recipients can be fractionated based on their high expression of CD43, CD44, and CD49e, and low or lack of expression of CD1 la, CD49d, and CD62L. In vitro studies demonstrate that these populations of Sca-1 in- engrafting ceils possess the majority of HPP-CFC, LPPCFC, and cells providing rapid in vitro expansion. However, based on the belief that primitive hematopoietic progenitor cells (HPC) represent a relatively quiescent population of stem cells, Sca-l+ lin" CD43+, CD44+, or CD49e+ (adhesion) cells would not be expected to be enriched for engrafting cells, since these three phenotypes contain a relatively high percentage of cycling cells (30% to 50% in S/G2+M) compared to their corresponding adhesion molecule-negative counterparts. This posed the question of whether primitive HPC were predominantly contained within the quiescent (Ga/G \) or mitotically active (S/G2+M) fractions of Sea-1+ lin" adhesion+ cells. To begin to investigate this, the three groups of Sca-l+ lin" adhésion cells were individually isolated and further fractionated based on their position in the cell cycle with the DNA dye Hoechst 33342. In vitro analysis revealed marked proliferative potential of both quiescent and cycling Sca-l+ lin" adhésion cells. To evaluate engraftment potential, a total of 103 Sca-l+ lin- adhésion Grj/Gi or S/G2+M cells isolated from SJL mice were transplanted into lethally irradiated C57/BI6 recipients along with 3 x 104 C57B1/6 competitor cells. The percentage of CD45.2 peripheral blood cells was used to estimate chimerism. Analysis of engraftment up to 3 months posttransplantation revealed the ability of cycling Sea-1+lin" adhésion cells to provide both myelopoiesis and lymphopoiesis in transplanted recipients. These data suggest that expression of CD43, CD44, and CD49e, independent of cell cycle status, may be a useful predictor of the engraftment potential of murine hematopoietic stem cells.
|Original language||English (US)|
|Number of pages||1|
|State||Published - Dec 1 1998|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology
- Cancer Research