Subpopulations of bone marrow fibroblasts support VLA-4-mediated migration of B-cell precursors.
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.
Tang
J
J
Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, NY.
Scott
G
G
Ryan
D H
DH
D000328:Adult; D000906:Antibodies / Q000276:immunology; D001402:B-Lymphocytes / Q000502:physiology*; D001854:Bone Marrow Cells; D015815:Cell Adhesion Molecules / Q000502:physiology; D002465:Cell Movement; D002478:Cells, Cultured; D005347:Fibroblasts / Q000502:physiology; D005353:Fibronectins / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D017469:Receptors, Fibronectin / Q000502:physiology; D016029:Receptors, Very Late Antigen / Q000502:physiology*; D019010:Vascular Cell Adhesion Molecule-1
D000906:Antibodies; D015815:Cell Adhesion Molecules; D005353:Fibronectins; D017469:Receptors, Fibronectin; D016029:Receptors, Very Late Antigen; D019010:Vascular Cell Adhesion Molecule-1