Culture of human fetal B-cell precursors on bone marrow stroma maintains highly proliferative CD20dim cells.
Growth of human B-cell precursors (BCP) was achieved by plating fetal CD10+ surface-mu (s mu)- cells in liquid medium onto bone marrow-derived fibroblastic stromal cell layers deprived of hematopoietic cells. Proliferation of the fetal BCP was strongly potentiated by the addition of interleukin-7 (IL-7) to the cultures. Cultures included both a stroma-adherent and -nonadherent fraction of lymphoid cells, allowing us to expand the number of input BCP to 13-fold. In the presence of exogenous IL-7, proliferation was dose-dependent relative to the number of stromal cells, demonstrating that soluble IL-7 does not act alone to promote optimal growth. We further showed that the lymphoid cells recovered remain CD10+ sIg- BCP and that most cells expressed the maturation-associated CD20 antigen when IL-7 was added to the cultures. Whereas both freshly isolated CD20- and CD20bright BCP proliferated in the presence of stroma, we observed that high-proliferative capacity CD20dim cells were maintained in the cultures. Finally, CD20dim sorted cells were shown to subsequently acquire high levels of CD20 expression in culture, thus demonstrating a partial maturation sequence. The present culture system thus represents a useful model for studying the regulatory signals in early human B lymphopoiesis.
Moreau
I
I
Schering-Plough Laboratory for Immunological Research, Dardilly, France.
Duvert
V
V
Banchereau
J
J
Saeland
S
S
D015703:Antigens, CD / Q000032:analysis*; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology*; D001854:Bone Marrow Cells; D002452:Cell Count; D002455:Cell Division; D002478:Cells, Cultured; D005260:Female; D005333:Fetus / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D015260:Neprilysin / Q000032:analysis; D010641:Phenotype; D011247:Pregnancy; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D017154:Stromal Cells / Q000502:physiology
D015703:Antigens, CD; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; D015260:Neprilysin