Human dendritic cells express the thrombopoietin receptor, c-Mpl.
Human thrombopoietin (TPO) is a haemopoietic growth factor that is essential for the growth and development of megakaryocytes. However, c-Mpl, the TPO receptor, has been detected in human leukaemic cell lines with a myelomonocytic phenotype. These results raise the possibility that dendritic cells (DC), a putative myeloid lineage cell, may also express c-Mpl and respond to TPO. In haemopoietic stem cell transplantation, DC could induce graft-versus-host disease by its strong antigen-presenting capacity. In this study we have examined the effect of TPO on differentiation and the antigen-presenting capacity of DC. To differentiate DC, cord blood CD34+ cells were cultured in the presence of a cytokine cocktail either in serum-free medium or RPMI1640 containing 10% fetal bovine serum. Flow cytometric analysis and immunocytochemical staining demonstrated that c-Mpl was expressed on DC. Furthermore, the expression of c-Mpl mRNA was detected in DC by RNase protection assay. However, when TPO was added to the culture system there were no significant changes in the differentiation and mixed leucocyte-stimulating capacity of DC. These findings suggest that TPO may be administered following cord blood transplantation without significant augmentation of antigen presentation mediated by DC.
Kumamoto
T
T
Department of Paediatrics and Clinical Immunology, Mie University School of Medicine, Tsu, Japan.
Azuma
E
E
Tanaka
M
M
Qi
J
J
Hirayama
M
M
Zhang
S L
SL
Kobayashi
M
M
Iwamoto
S
S
Komada
Y
Y
Yamamoto
H
H
Nakashima
K
K
Sakurai
M
M
D002455:Cell Division; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D005312:Fetal Blood; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007963:Leukocytes, Mononuclear / Q000166:cytology; D009363:Neoplasm Proteins; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D013926:Thrombopoietin / Q000378:metabolism
D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; D013926:Thrombopoietin