Peripheral Blood CD34+ Cells Differ From Bone Marrow CD34+ Cells in Thy-l Expression and Cell Cycle Status in Nonhuman Primates Mobilized or Not Mobilized With Granulocyte Colony-Stimulating Factor and/or Stem Cell Factor

Granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) have been shown t o stimulate the circulation of hematopoietic progenitor cells in both mice and nonhuman primates. We evaluated the immunophenotype and cell cycle status of CD34+ cells isolated from the bone marrow (BM) and leukapheresis product of cytokine-mobilized nonhuman primates. CD34+ cells were isolated from rhesus macaques that had received no cytokine therapy, 100 pg/kg/d G-CSF, 200 pg lkg ld SCF, or a combination of both 100 pglkgld GCSF and 200 pglkgld SCF as a subcutaneous injection for 5 days. BM was aspirated before (day 0) and on the last day (day 5) of cytokine administration. On days 4 and 5, peripheral blood IPB) mononuclear cells were collected using a novel method of leukapheresis. Threefold more PB mononuclear cells were collected from animals receiving G-CSF alone or G-CSF and SCF than from animals that had received either SCF alone or no cytokine therapy. CD34+ cells were positively selected using an immunoadsorptive system from the BM, PB, andlor leukapheresis product. Threefold and 10fold more CD34' cells were isolated from the leukapheresis product of animals receiving G-CSF or G-CSF and SCF, respectively, than from animals receiving no cytokine therapy