Objectives: Human hematopoietic stem cell (HSC)-containing grafts are most commonly used to treat various blood diseases, including leukemias and autoimmune disorders. CD150 (SLAM) family receptors have recently been shown to be differentially expressed by mouse HSC and progenitor cells. Members of the CD150 family are key regulators of leukocyte activation and differentiation. The goal of the present study is to analyze the expression patterns of the CD150 receptors CD48, CD84, CD150 (SLAM), CD229 (Ly9), and CD244 (2B4) on the different sources of human hematopoietic stem and progenitor cells.
Materials and methods: Expression of CD150 receptors was analyzed on human mobilized peripheral blood CD133(+)-isolated cells and CD34(+) bone marrow (BM) and umbilical cord blood (CB) cells using multicolor flow cytometry.
Results: CD244 was present on most CD133(+)Lin(-)-mobilized cells and CD34(+)Lin(-) BM and CB cells, including virtually all CD38(-)Lin(-) primitive progenitor cells. CD48 had a restricted expression pattern on CD133(+)Lin(-)CD38(-) cells, while its levels were significantly higher in CD34(+)Lin(-) BM and CB cells. In addition, CD84 was present on a significant number of CD133(+)Lin(-) cells, but only on a small fraction of CD133(+)Lin(-)CD38(-) peripheral blood mobilized cells. In contrast, CD84 was expressed on practically all CD34(+)Lin(-) BM cells. No CD150 expression was observed in mobilized peripheral blood CD133(+)Lin(-) or CD34(+)Lin(-) BM and CB cells. Furthermore, only a small fraction of CD34(+)Lin(-) BM and CB cells expressed CD229.
Conclusions: Our results show that CD150 family molecules are present on human hematopoietic stem and progenitor cells and that their expression patterns differ between humans and mice.