Isolation of permanent clonal bone marrow stromal cell lines derived from "viable moth-eaten" and "severe combined immunodeficiency" mutant mice.

Long-term bone marrow cultures (LTBMCs) were established from bone marrow of mev/mev mice with severe combined immunodeficiency (scid) and their normal littermates, and permanent stromal cell lines were derived. In cultures from mutant mev/mev mice, an adherent layer containing around 10% of fibro-endothelial cells and 90% macrophage-like cells was observed. A permanent cell line actively inhibited hematopoiesis resulting in an 80-fold decrease in production of cumulative colony-forming unit culture units (CFU) including granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM) and granulocyte-macrophage (CFU-GM). To confirm active inhibition, we performed coculture experiments using permanent cell lines and engrafted each in vitro with hematopoietic progenitors from normal mouse LTBMCs. "Cobblestone island" and nonadherent cell production were observed adding hemopoietic progenitors to coculture of fibroblastic cells of mev/mev cultures with lines from normal littermates. In contrast, macrophage cell line Mev #5 suppressed hemopoiesis and itself had a proliferative advantage. Thus, bone marrow stromal cell lines from mev/mev mice reproduce some characteristics of the hematopoietic microenvironmental defect in vitro.