Expression of homing-associated cell adhesion molecule (H-CAM/CD44) on human CD34 + hematopoietic progenitor cells

• Published in: Experimental hematology Vol. 27; no. 3; pp. 542 - 552
• Main Authors: Deguchi, Takao, Komada, Yoshihiro, Sugiyama, Kenji, Zhang, Xao-Li, Azuma, Eiichi, Yamamoto, Hatsumi, Sakurai, Minoru
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01-03-1999
• Subjects: Adult; Antigens, CD19 - analysis; Antigens, CD34 - analysis; Apoptosis; Blood Cells; Bone Marrow Cells; CD44—Hematopoiesis—Apoptosis—Hematopoietic progenitor cells; Cell Differentiation; Cell Lineage; Cell Separation; Cells, Cultured; Coculture Techniques; Fetal Blood - cytology; Flow Cytometry; Hematopoietic Stem Cells - classification; Hematopoietic Stem Cells - metabolism; Humans; Hyaluronan Receptors - biosynthesis; Hyaluronan Receptors - genetics; Infant, Newborn; Neprilysin - analysis; Organ Specificity; Stromal Cells - cytology; CD44—Hematopoiesis—Apoptosis—Hematopoietic progenitor cells
• ISSN: 0301-472X; 1873-2399
• DOI: 10.1016/S0301-472X(98)00047-2

We investigated the expression of CD44 molecule on CD34
+ hematopoietic progenitor cells. Significantly lower expression of CD44 was observed on bone marrow (BM) CD34
+ cells compared with circulating CD34
+ cells in cord blood and peripheral blood. Using fluorescence-activated cell sorting, human CD34
+ BM cells were fractionated into CD44
+ and CD44
− populations. Immunofluorescence analysis revealed that the majority of CD34
+CD44
− cells expressed B-lymphocyte–associated CD10 and CD19 antigens, whereas only a part of CD34
+CD44
+ cells were positive for CD19. Myeloid and erythroid progenitor cells were found predominantly in CD34
+ CD44
+ cell fractions. In short-term suspension cultures, cell proliferation and G
1
→ S transition in the cell cycle were enhanced in CD34
+CD44
+ cells. In contrast, a large part of CD34
+CD44
− cells underwent apoptotic cell death. Although co-culture with BM stromal cells could partially prevent CD34
+CD44
− cells from undergoing apoptosis, significant increase of apoptotic cells was consistently observed. Furthermore, CD34
+CD44
− cells plated on BM stromal cells could differentiate into CD34
−CD44
−CD10
−CD19
+ cells. These findings suggest that CD34
+CD44
− cells expressing CD19 would represent unique B-lymphocyte–committed precursors in BM, which might undergo apoptotic cell death in the early steps of B-cell differentiation.