Relationships between B‐lineage lymphocytes and stromal cells in long‐term bone marrow cultures

Abstract

In long-term culture of mouse bone marrow, the growth and differentiation of B-lineage lymphocytes depends on interaction with adherent cells or their products. The objectives of these studies were to characterize the types of cells present in the supporting adherent layer as well as the physical relationships of these cells with lymphocytes. With an extensive panel of antibodies against hemopoietic and lymphocyte antigens, two discrete nonlymphoid populations were identified: macrophages and undefined, large cells which we termed "stromal cells". Lymphocyte clusters grew in actual contact with the latter cells only. Stromal cells lacked expression of most hemopoietic antigens, including the common leukocyte antigen, J11d, heat stable antigen (M1/69), Thy-1 and BP 1. Antigens expressed by stromal cells were detected by AA4.1, our 94.2 antibody, and antibody to the Forsmann antigen, but the most distinguishing characteristics of the lymphocyte-binding stromal cells were production of basement membrane components, laminin and collagen IV, and the extremely low uptake of acetylated low density lipoprotein (LDL). Using acetylated LDL uptake as a sorting criterion, the lymphocyte-binding stromal cells were separated from the macrophages, recultured and shown to support lymphocyte proliferation. We found the binding between stromal cells and lymphocytes to be highly selective and dependent on divalent cations; hence, specialized adhesion mechanisms may have a role in B cell development. Moreover, our studies suggest that phosphatidylinositol-anchored cell surface molecules may be involved in this adhesion. Our findings demonstrate the possibility that a single cell type provides physical support and proliferation stimuli for early B-lineage cells. This accessory cell is not a macrophage; rather, it has features of an endothelial or epithelial cell.

Calcitonin-gene related peptide (CGRP) inhibits interleukin-7-induced pre-B cell colony formation

“…The cultures we used were able to support the growth and proliferation of primary B cell precursors. They consisted primarily of macrophages and a larger epithelial-like population of cells, similar to what has been reported previously [29][30][31][32]34].…”

“…The treated media was collected, sterile filtered, and stored at Ϫ20°C until assayed. Morphologically, these cultures were similar to those described earlier by other investigators [29][30][31][32][33][34]. Microscopic examination of the adherent cells revealed that the predominant cell type had a macrophage-like morphology.…”

“…B cell-supporting adherent monolayers were set a up as described by Whitlock and Witte [29,30]. As described previously, these cultures appeared to contain two predominant cell types, a large proportion of cells having a macrophage-like morphology with a smaller number of larger epithelial-like cells [29][30][31][32]34]. FACS analysis with antibodies to Mac-1 showed that the cultures contained 70-80% macrophages.…”

IFN‐γ activation of mesenchymal stem cells for treatment and prevention of graft versus host disease

“…To obtain MSC, BM cells were plated at a density of 20 Â 10 6 / 9.6 cm 2 in MSC media at 37 C in 5% C0 2 as previously described [63][64][65]. The nonadherent population was removed after 72 h and the adherent cells were washed with fresh media and cultured for 7 additional days.…”

Morphological study of thymus stromal cells (TEL-2 cell) which play a role in the elimination of double positive immature thymocytes by phagocytosis

“…First, the immature DP thymocytes in the mouse in vitro undergo phenotypic alteration, follow the stages of rapid (within a few hours) development, and express a diversity of markers of CD4 CD8, and TCR ranging from CD810CD410TCR10 to (lD8hicD4hiTCiVF~'iOUS Stage (reviewed in Pawlowski and Staery, 1994;NikoliC-hgie, 1991). Second, the lymphocyte clusters grow in actual contact with the stroma1 cells (Singer et al, 1986;Witte et al, 1987).…”