Interleukin-7 contributes to human pro-B-cell development in a mouse stromal cell-dependent culture system.
OBJECTIVE
The role of interleukin (IL)-7 in human B lymphopoiesis is still controversial. We used an in vitro culture system to verify involvement of IL-7 in development of human pro-B cells from hematopoietic stem cells.


METHODS
Human CD34(+) bone marrow cells were cultured for 4 weeks on MS-5 mouse stromal cells to induce pro-B cells. Expression of IL-7 receptor alpha or other B-cell differentiation marker genes on cultured human CD34(+)bone marrow cells was investigated by reverse transcription polymerase chain reaction (RT-PCR). Colony assay of human CD34(+) bone marrow cells was also performed to determine the effect of IL-7 on colony-forming ability. Neutralizing antibody or reagent that eliminates the effect of IL-7 was added to the culture system, and the number of pro-B cells induced was estimated by flow cytometry.


RESULTS
RT-PCR analysis revealed mRNA expression of IL-7 receptor alpha as well as B-cell differentiation marker genes in not only CD19(+) pro-B cells but also CD19(-) CD33(-) cells induced from CD34(+) bone marrow cells after cultivation for 4 weeks on MS-5 cells. Addition of anti-mouse IL-7 antibody, anti-human IL-7 receptor alpha antibody, or JAK3 kinase inhibitor reduced the number of pro-B cells induced, demonstrating that elimination of IL-7 reduces pro-B-cell development. Addition of anti-mouse IL-7 antibody emphasized the colony-forming ability of burst-forming unit erythroid cells.


CONCLUSIONS
IL-7 produced by MS-5 cells is required for human pro-B-cell development from CD34(+)bone marrow cells in our culture system, and IL-7 appears to play a certain role in early human B lymphopoiesis.
Taguchi
Tomoko
T
Department of Developmental Biology, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan.
Takenouchi
Hisami
H
Shiozawa
Yusuke
Y
Matsui
Jun
J
Kitamura
Noriko
N
Miyagawa
Yoshitaka
Y
Katagiri
Yoko U
YU
Takahashi
Takao
T
Okita
Hajime
H
Fujimoto
Junichiro
J
Kiyokawa
Nobutaka
N
D000818:Animals; D018952:Antigens, CD34; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D001854:Bone Marrow Cells / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D006801:Humans; D015851:Interleukin-7 / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D017154:Stromal Cells / Q000166:cytology*
D018952:Antigens, CD34; D015851:Interleukin-7