title: Hematopoiesis: The Role of Stromal Integrin Interactions in Pro-B Cell Proliferation.
abstract: Recent studies using long term bone marrow cultures have concluded that adherence of lymphoid precursors to the underlying stromal cells is required for normal B cell development. However, the function of specific integrin interactions in B cell development remains unresolved. In our laboratory, we observed that maximal proliferation of pro-B cells required the presence of stromal cells and that stromal cytokines alone could not replace the requirement for stromal cell contact. For that reason, we questioned whether integrin interactions play a role in regulating pro-B cell proliferation in the bone marrow. Murine pro-B cell line Cl.92 expressed VLA-4, CD44, and fibronectin-receptor. Abrogation of binding of these molecules to stromal cell ligands using blocking antibodies resulted in failure of pro-B cell adherence and significant decreases in pro-B cell proliferation. Disruption of single integrin interactions did not compromise either adhesion of pro-B cells to stromal cells or IL-7 stimulated proliferation. Taken together, these data suggest that normal pro-B cells interact with stromal cells through multiple integrin interactions and that integrin mediated potentiation of pro-B cell proliferation is functionally redundant and not affected by failure of single ligand interactions.
authors.affiliation: Blood and Marrow Transplantation Program of the Mary Babb Randolph Cancer Center.
authors.forename: BRANDI K.
authors.initials: BK
authors.lastname: Hahn
authors.forename: DEBRA
authors.initials: D
authors.lastname: Piktel
authors.forename: LAURA F.
authors.initials: LF
authors.lastname: Gibson
authors.forename: KENNETH S.
authors.initials: KS
authors.lastname: Landreth