Functional CD5+ B cells develop predominantly in the spleen of NOD/SCID/gammac(null) (NOG) mice transplanted either with human umbilical cord blood, bone marrow, or mobilized peripheral blood CD34+ cells.
OBJECTIVE
Human CD5+ B cells are the major B cell subset in fetal spleen and umbilical cord blood (CB), and their number gradually diminishes in both spleen and peripheral blood from infancy through childhood while conventional B cells increase. In this study, we investigated whether CD5+ cells differentiate from adult hematopoietic stem cells (HSCs) as well as fetal ones in immunodeficient mice.


METHODS
In our system, NOD/SCID/gammac(null) (NOG) mice were transplanted with CD34+ cells from CB (hCB model), adult bone marrow (hBM model), and mobilized peripheral blood (hMPB model).


RESULTS
In these model mice, a high proportion of CD19+IgM+CD5+ mature B cells appeared in the spleen, regardless of the CD34+ cell origin, 4 to 8 weeks after transplantation, while the majority were CD19+IgM-CD5- immature B cells in BM. The CD19+CD5- BM cells showed to express CD5 after the coculture with NOG spleen cells. In the sera of immunized hCB model mice with DNP-KLH, antigen-specific IgM but not IgG was enhanced.


CONCLUSIONS
Our results show that adult CD34+ cells develop into functional CD5+ B cells in NOG spleen as much as fetal CD34+ cells do.
Matsumura
Takuya
T
Third Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Kametani
Yoshie
Y
Ando
Kiyoshi
K
Hirano
Yasuyuki
Y
Katano
Ikumi
I
Ito
Ryoji
R
Shiina
Masashi
M
Tsukamoto
Hideo
H
Saito
Yuki
Y
Tokuda
Yutaka
Y
Kato
Shunichi
S
Ito
Mamoru
M
Motoyoshi
Kazuo
K
Habu
Sonoko
S
D000818:Animals; D018952:Antigens, CD34 / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D018956:CD5 Antigens / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology*; D019070:Cell Lineage / Q000276:immunology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D033581:Stem Cell Transplantation; D014183:Transplantation, Heterologous
D018952:Antigens, CD34; D018956:CD5 Antigens