Biological characterization of cloned permanent stromal cell lines from anemic Sl/Sld mice and +/+ littermates.

Permanent cloned bone marrow stromal cell lines, designated Sld1, Sld2, Sld3, were derived from long-term bone marrow cultures (LTBMC) of Sl/Sld mice and littermate WCB6F1 mice (designated +/+1, +/+2, +/+1.10, and +/+2.4). Production of extracellular matrix proteins by these cell lines was detected using specific antibodies. Fibronectin, laminin, and collagen type IV were detected in all clonal cell lines tested. Each cloned stromal cell line or parent stromal cell culture was also tested in vitro for support of engrafted hemopoietic stem cells. Engrafted hemopoietic stem cells from C57BL/6J LTBMCs forming CFU-GEMM and BFUe colonies were supported at 76% and 44% efficiency by lines +/+2.4 and +/+1.10, respectively, compared to the number recovered from parent uncloned C57BL/6J stromal cell cultures. In contrast, cell lines Sld1 and Sld3 were significantly less supportive of CFU-GEMM progenitor cells (14% and 18% efficiency, respectively) and erythroid progenitors (6% and less than 0.1% efficiency, respectively). Some Sld lines also showed reduced support compared to +/+ cell lines of a clonal multipotential erythroid cell line B6SUtA. These permanent stromal cell lines should be useful in elucidation of the specific microenvironmental factors required for support of multilineage and erythroid progenitor cells.