Submitted October 31, 2005
Accepted April 13, 2006
Increasing Flt3L availability alters composition of a
novel bone marrow lymphoid progenitor compartment
Rhodri Ceredig, Melanie Rauch, Gina Balciunaite, and Antonius G Rolink*
Center for Biomedicine, Developmental and Molecular Immunology, University of Basel
* Corresponding author; email: antonius.rolink{at}unibas.ch.
We have recently described a CD19- B220+ CD117low bone
marrow subpopulation with B, T and myeloid developmental
potential which we have called EPLM. These cells also
expressed Fms-like tyrosine kinase 3, Flt3 or CD135.
Treatment of mice with the corresponding ligand, Flt3L,
showed a fifty-fold increase in EPLM. In addition to
the expected increase in dendritic cell numbers, Flt3L
treatment had a reversible inhibitory effect on B
lymphopoiesis. Limiting dilution analysis of sorted EPLM
from Flt3L treated mice showed that B lymphocyte
progenitor activity was reduced twenty-fold, but that
myeloid and T cell progenitor activity was largely
preserved. EPLM from treated mice transiently
reconstituted the thymus and bone marrow of recipient
mice, generating cohorts of functional T and B cells in
peripheral lymphoid organs. Thus, Flt3L treatment
results in a dramatic increase in a novel bone marrow
cell with lymphoid and myeloid progenitor activity.
