CD34+/CD105+ cells are enriched in primitive circulating progenitors residing in the G0 phase of the cell cycle and contain all bone marrow and cord blood CD34+/CD38low/- precursors.
A subset of circulating CD34+ cells was found to express CD105 antigen. Sorting experiments showed that most granulocyte-macrophage colony-forming units (GM-CFU) and burst-forming units - erythroid (BFU-E) were retained in the CD34+/CD105- fraction, whereas rare GM-CFU/BFU-E were generated from CD34+/CD105+ cells. Megakaryocytic aggregates were entirely retained in the CD34+/CD105+ fraction. Neutralizing doses of an anti-TGF-beta1 antibody demonstrated CD34+/CD105+ cells capable of colony-forming activity without any significant effect on CD34+/CD105- cells. Cloning of secondary colonies revealed that CD34+/CD105+ cells had a significantly higher secondary cloning efficiency than CD34+/CD105- cells. CD34+/CD105+ cells had a significantly higher long-term culture-initiating cell (LTC-IC) frequency than CD34+/CD105- cells. Kinetic analysis showed that 75% of CD34+/CD105+ cells consisted of DNA 2n G0Ki-67- cells whereas 82% of CD34+/CD105- were DNA 2n G1Ki-67+ cells, and this latter subset showed a RNA content consistently higher than CD34+/CD105+ cells. CD34+/CD105+ progenitors were CD25+, whereas CD34+/CD105- contained a small CD25+ subset. Three-colour analysis of bone marrow and cord blood CD34+ cells demonstrated that all the CD34+/CD38low/- primitive precursors were contained in CD34+/CD105+ cells. Extensive characterization of these CD105+ precursors indicated that they have biological properties associated with primitive haematopoietic precursors.
Pierelli
L
L
Cattedra di Ematologia; Istituto di Ostetricia e Ginecologia, Universitá Cattolica del Sacro Cuore, Roma, Italy. Lpierelli@nexus.it
Scambia
G
G
Bonanno
G
G
Rutella
S
S
Puggioni
P
P
Battaglia
A
A
Mozzetti
S
S
Marone
M
M
Menichella
G
G
Rumi
C
C
Mancuso
S
S
Leone
G
G
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000328:Adult; D000704:Analysis of Variance; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000276:immunology*; D000943:Antigens, Differentiation / Q000276:immunology; D001854:Bone Marrow Cells / Q000276:immunology*; D002455:Cell Division; D000071063:Endoglin; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology*; D005434:Flow Cytometry / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D008562:Membrane Glycoproteins; D009244:NAD+ Nucleosidase / Q000276:immunology; D010051:Ovarian Neoplasms / Q000473:pathology; D011956:Receptors, Cell Surface; D016192:Resting Phase, Cell Cycle; D019010:Vascular Cell Adhesion Molecule-1 / Q000276:immunology*
D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; C064206:ENG protein, human; D000071063:Endoglin; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1