Interactions between c-kit and stem cell factor are not required for B-
cell development in vivo
S Takeda, T Shimizu and HR Rodewald
Basel Institute for Immunology, Switzerland.
The receptor-type tyrosine kinase, c-kit is expressed in hematopoietic stem
cells (HSC), myeloid, and lymphoid precursors. In c-kit ligand- deficient
mice, absolute numbers of HSC are mildly reduced suggesting that c-kit is
not essential for HSC development. However, c-kit- HSC cannot form spleen
colonies or reconstitute hematopoietic functions in lethally irradiated
recipient mice. Based on in in vitro experiments, a critical role of c-kit
in B-cell development was suggested. Here we have investigated the B-cell
development of c-kit-null mutant (W/W) mice in vivo. Furthermore, day 13
fetal liver cells from wild type or W/W mice were transferred into
immunodeficient RAG-2-/- mice. Surprisingly, transferred c-kit- cells gave
rise to all stages of immature B cells in the bone marrow and subsequently
to mature conventional B2, as well as B1, type B cells in the recipients to
the same extent as transferred wild type cells. Hence, in contrast to
important roles of c-kit in the expansion of HSC and the generation of
erythroid and myeloid lineages and T-cell precursors, c-kit- HSC can
colonize the recipient bone marrow and differentiate into B cells in the
absence of c-kit.
Volume 89,
Issue 2,
pp. 518-525,
01/15/1997
Copyright © 1997 by The American Society of Hematology
