Selective expression of the receptor tyrosine kinase, HTK, on human erythroid progenitor cells

Tomohisa Inada, Atsushi Iwama, Seiji Sakano, Mitsuharu Ohno, Ken Ichi Sawada, Toshio Suda

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Abstract

HTK is a receptor tyrosine kinase of the Eph family. To characterize the involvement of HTK in hematopoiesis, we generated monoclonal antibodies against HTK and investigated its expression on human bone marrow cells. About 5% of the bone marrow cells were HTK+, which were also c-Kit+, CD34(low), and glycophorin A(-/low). Assays of progenitors showed that HTK+c-Kit+ cells consisted exclusively of erythroid progenitors, whereas HTK-c-Kit+ cells contained progenitors of granulocytes and macrophages as well as those of erythroid cells. Most of the HTK+ erythroid progenitors were stem cell factor-dependent for proliferation, indicating that they represent mainly erythroid burst-forming units (BFU-E). During the erythroid differentiation of cultured peripheral CD34+ cells, HTK expression was upregulated on immature erythroid cells that corresponded to BFU-E and erythroid colony- forming units and downregulated on erythroblasts with high levels of glycophorin expression. These findings suggest that HTK is selectively expressed on the restricted stage of erythroid progenitors, particularly BFUE, and that HTK is the first marker antigen that allows the purification of erythroid progenitors. Furthermore, HTKL, the ligand for HTK, was expressed in the bone marrow stromal cells. Our findings provide a novel regulatory system of erythropoiesis mediated by the HTKL-HTK signaling pathway.

Original languageEnglish
Pages (from-to)2757-2765
Number of pages9
JournalBlood
Volume89
Issue number8
Publication statusPublished - 1997 Apr 15

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ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

Cite this

Inada, T., Iwama, A., Sakano, S., Ohno, M., Sawada, K. I., & Suda, T. (1997). Selective expression of the receptor tyrosine kinase, HTK, on human erythroid progenitor cells. Blood, 89(8), 2757-2765.