Subpopulations of bone marrow fibroblasts support VLA-4-mediated migration
of B-cell precursors
J Tang, G Scott and DH Ryan
Department of Pathology and Laboratory Medicine, University of Rochester
Medical Center, NY.
Proliferation of normal human lymphoid progenitors in culture is dependent
on interaction with bone marrow-derived fibroblast-like cells (BM-FB). To
investigate possible heterogeneity in this lymphoid- supportive
microenvironment, we studied the interaction of a human B- precursor cell
line (NALM-6) with BM-FB. NALM-6 cells associate with BM- FB by either
adhesion or migration underneath the fibroblast. Individual fibroblasts in
the BM-FB layer showed significant variation in the number of migrating
NALM-6 cells. Migration of NALM-6 cells was primarily VLA-4-dependent,
although residual migration observable after blocking with anti-VLA-alpha 4
antibody was inhibited by anti-VLA-alpha 5 antibody. Migration was not
inhibited by blocking either of the known VLA-4 counterreceptors (VCAM-1 or
fibronectin), although slight inhibition was observed using a combination
of blocking antibodies to VCAM-1 and fibronectin. In contrast, NALM-6
adhesion without migration was significantly inhibitable by anti-VCAM-1
antibody. VCAM-1 or fibronectin expression on individual BM-FB did not
correlate with NALM- 6 migration. These results indicate that the adhesion
and migration of human B-lymphoid precursors in the bone marrow
microenvironment are mechanistically separable events and suggest the
possibility of novel VLA-4 ligand(s), which may be important in human
lymphopoiesis. Subpopulations of cells in the bone marrow microenvironment
may preferentially support important aspects of lymphoid progenitor
development.
Volume 82,
Issue 11,
pp. 3415-3423,
12/01/1993
Copyright © 1993 by The American Society of Hematology
