T-cell-specific expression of kinase-defective Eph-family receptor protein, EphB6 in normal as well as transformed hematopoietic cells.
Although most kinase-defective growth factor receptor proteins are associated with pathogenic conditions, a kinase-defective Eph-family receptor protein, EphB6, is expressed in normal human tissues. We generated monoclonal antibodies specific for human EphB6 to characterize its expression on human hematopoietic cells. A very small population of normal human peripheral white blood cells (0.57 +/- 0.07%, n = 12) expressed EphB6. The EphB6-positive cells were CD2+, CD7+, CD3+ and CD4+ or CD8+ lymphocytes, but they did not express CD19 or CD11b. In human bone marrow, only 1.5 +/- 0.19% of lymphocytes expressed EphB6. Compared with the expression in peripheral lymphocytes, prominent expression of EphB6 protein was demonstrated in CD4+CD8+ double-positive mouse thymocytes. The T-cell lineage-specific expression was strictly conserved in human leukemia/lymphoma cells. Among T-cell-derived leukemia cells, the expression level of EphB6 seemed to decrease with maturation of the cells. These results suggest that EphB6 expression is regulated in T-cell development.
Shimoyama
M
M
Department of Medicine, Kobe University School of Medicine, Japan.
Matsuoka
H
H
Tamekane
A
A
Ito
M
M
Iwata
N
N
Inoue
R
R
Chihara
K
K
Furuya
A
A
Hanai
N
N
Matsui
T
T
D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D019070:Cell Lineage; D002471:Cell Transformation, Neoplastic; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D051379:Mice; D011505:Protein-Tyrosine Kinases / Q000172:deficiency; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics*; D013601:T-Lymphocytes / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases