Bcl-2 Expression in Acute Myeloblastic Leukaemia: Relationship with Autonomous Growth and CD34 Antigen Expression

Transgenic mice have been generated with expression of the herpes virus thymidine kinase gene directed by a 2.7-kb fragment of the IIb murine promoter of the gene encoding the IIb-subunit of the platelet integrin IIbβ3 (Tropel et al, Blood90:2995, 1997). Administration of ganciclovir (GCV) to these mice resulted not only in an acute cessation of platelet production due to the depletion of the megakaryocytic lineage, but also a decrease in erythrocyte and leukocyte numbers. Immunogold staining on ultrathin frozen sections and electron microscopy has now shown that the remaining population of immature hematopoietic cells contain a high proportion of Sca-1+ and CD34+ cells, with CD45R+ cells of the lymphopoietic lineage being maintained. Stromal cells were also preserved. Blood thrombopoietin levels were high. At 4 days of the recovery phase, Sca-1 and CD34 antigen expression decreased with intense proliferation of cells of the three lineages, with megakaryocyte (MK) progenitors being identified by their positivity for glycoprotein IIb-IIIa. These results suggest that transcriptional activity for the IIb gene promoter was present on pluripotent hematopoietic stem cells. At 6 to 8 days after cessation of GCV, numerous mature MK were observed, some of them with deformed shapes crossing the endothelial barrier through thin apertures. Proplatelet production was visualized in the vascular sinus. After 15 days, circulating platelet levels had increased to approximately 65% of normal. Transgenic IIb-tk mice constitute a valuable model to study in vivo megakaryocytopoiesis. © 1998 by The American Society of Hematology.

Download Full-text

CD34 antigen expression of acute myeloid leukemia-colony forming cells

The International Journal Of Cell Cloning ◽

10.1002/stem.5530100733 ◽

1992 ◽

Vol 10 (S1) ◽

pp. 98-100 ◽

Cited By ~ 2

Author(s):

F. Silvestri ◽

S. Banavali ◽

M. Yin ◽

B. Hulette ◽

V. Gopal ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Antigen Expression ◽

Cd34 Antigen ◽

Acute Myeloid

Download Full-text

CD34 expression by stromal precursors in normal human adult bone marrow

Blood ◽

10.1182/blood.v78.11.2848.bloodjournal78112848 ◽

1991 ◽

Vol 78 (11) ◽

pp. 2848-2853 ◽

Cited By ~ 4

Author(s):

PJ Simmons ◽

B Torok-Storb

Keyword(s):

Bone Marrow ◽

Bone Marrow Cells ◽

Complex Mixture ◽

Antigen Expression ◽

Cell Types ◽

Stromal Precursors ◽

Cd34 Antigen ◽

Distinct Cell ◽

Marrow Cells

Normal bone marrow cells were isolated by fluorescence-activated cell sorting (FACS) on the basis of CD34 antigen expression and then assayed in vitro for colonies of fibroblastic cells (fibroblast colony-forming units [CFU-F]). Greater than 95% of detectable CFU-F were recovered in the CD34+ population, while their numbers were markedly depleted in the CD34- population. Additional experiments showed that the majority of CFU-F exhibited high forward and perpendicular light scatter and low- density CD34 antigen. Growth of sorted cells in medium optimized for long-term marrow culture (LTMC) produced a complex mixture of adherent stromal elements including fibroblasts, adipocytes, smooth muscle cells, and macrophages. Monoclonal antibody STRO-1, which identifies bone marrow stromal cells, reacted with approximately 5% of CD34+ cells, which included all CFU-F and stromal precursors in LTMC. Experiments using soybean agglutinin (SBA) further showed that these stromal elements were restricted to a population of bone marrow cells with the phenotype CD34+/SBA+. These properties of stromal precursors are quite distinct from those of primitive hematopoietic progenitors, showing that although the precursors of the hematopoietic and stromal systems share expression of CD34, they are otherwise phenotypically distinct cell types.

Download Full-text

CD34 expression by stromal precursors in normal human adult bone marrow

Blood ◽

10.1182/blood.v78.11.2848.2848 ◽

1991 ◽

Vol 78 (11) ◽

pp. 2848-2853 ◽

Cited By ~ 185

Author(s):

PJ Simmons ◽

B Torok-Storb

Keyword(s):

Bone Marrow ◽

Bone Marrow Cells ◽

Complex Mixture ◽

Antigen Expression ◽

Cell Types ◽

Stromal Precursors ◽

Cd34 Antigen ◽

Distinct Cell ◽

Marrow Cells

Abstract Normal bone marrow cells were isolated by fluorescence-activated cell sorting (FACS) on the basis of CD34 antigen expression and then assayed in vitro for colonies of fibroblastic cells (fibroblast colony-forming units [CFU-F]). Greater than 95% of detectable CFU-F were recovered in the CD34+ population, while their numbers were markedly depleted in the CD34- population. Additional experiments showed that the majority of CFU-F exhibited high forward and perpendicular light scatter and low- density CD34 antigen. Growth of sorted cells in medium optimized for long-term marrow culture (LTMC) produced a complex mixture of adherent stromal elements including fibroblasts, adipocytes, smooth muscle cells, and macrophages. Monoclonal antibody STRO-1, which identifies bone marrow stromal cells, reacted with approximately 5% of CD34+ cells, which included all CFU-F and stromal precursors in LTMC. Experiments using soybean agglutinin (SBA) further showed that these stromal elements were restricted to a population of bone marrow cells with the phenotype CD34+/SBA+. These properties of stromal precursors are quite distinct from those of primitive hematopoietic progenitors, showing that although the precursors of the hematopoietic and stromal systems share expression of CD34, they are otherwise phenotypically distinct cell types.

Download Full-text

Ultrastructural Analysis of Bone Marrow Hematopoiesis in Mice Transgenic for the Thymidine Kinase Gene Driven by the IIb Promoter

Blood ◽

10.1182/blood.v92.6.2012 ◽

1998 ◽

Vol 92 (6) ◽

pp. 2012-2023 ◽

Cited By ~ 19

Author(s):

Christel Poujol ◽

Diana Tronik-Le Roux ◽

Philippe Tropel ◽

Valérie Roullot ◽

Alan Nurden ◽

...

Keyword(s):

Thymidine Kinase ◽

Gene Promoter ◽

Antigen Expression ◽

Recovery Phase ◽

Thymidine Kinase Gene ◽

Kinase Gene ◽

Immunogold Staining ◽

Hematopoietic Stem ◽

Cd34 Antigen

Abstract Transgenic mice have been generated with expression of the herpes virus thymidine kinase gene directed by a 2.7-kb fragment of the IIb murine promoter of the gene encoding the IIb-subunit of the platelet integrin IIbβ3 (Tropel et al, Blood90:2995, 1997). Administration of ganciclovir (GCV) to these mice resulted not only in an acute cessation of platelet production due to the depletion of the megakaryocytic lineage, but also a decrease in erythrocyte and leukocyte numbers. Immunogold staining on ultrathin frozen sections and electron microscopy has now shown that the remaining population of immature hematopoietic cells contain a high proportion of Sca-1+ and CD34+ cells, with CD45R+ cells of the lymphopoietic lineage being maintained. Stromal cells were also preserved. Blood thrombopoietin levels were high. At 4 days of the recovery phase, Sca-1 and CD34 antigen expression decreased with intense proliferation of cells of the three lineages, with megakaryocyte (MK) progenitors being identified by their positivity for glycoprotein IIb-IIIa. These results suggest that transcriptional activity for the IIb gene promoter was present on pluripotent hematopoietic stem cells. At 6 to 8 days after cessation of GCV, numerous mature MK were observed, some of them with deformed shapes crossing the endothelial barrier through thin apertures. Proplatelet production was visualized in the vascular sinus. After 15 days, circulating platelet levels had increased to approximately 65% of normal. Transgenic IIb-tk mice constitute a valuable model to study in vivo megakaryocytopoiesis. © 1998 by The American Society of Hematology.

Download Full-text