Bone marrow stromal cells modulate both kappa light chain and Ly1 antigen expression on Ly1+ pre-B cell lines in vitro

Abstract

Murine Ly1+ pre-B cell lines, including 70Z/3 and three pre-B cell lines derived from long-term bone marrow cultures, exhibited selective adherence to bone marrow stromal cells. In contrast, splenic B cells, the A20 B-cell lymphoma, and four Ly1- B cell lines derived from long- term bone marrow cultures failed to adhere substiantially to bone marrow cultures failed to adhere substiantially to bone marrow stroma. Ly1+ pre-B cell lines were induced to express kappa light chains by exposure to either lipopolysaccharide (LPS), recombinant interleukin-1 (IL-1), or stromal cells. However, induction of kappa light chains failed to prevent pre-B cell adherence to stromal cells. Supernatants derived from primary bone marrow stromal cells decreased Ly1 expression on the Ly1+ pre-B cell lines. These experiments suggest that (1) expression of immunoglobulin light chains by developing Ly1+ pre-B cells is mediated by bone marrow stromal cells; (2) loss of specific adherence to stroma is progressive and occurs post-light chain induction; and (3) soluble products of stromal cells may downregulate expression of surface Ly1 on otherwise Ly1+ pre-B cells. The importance of these observations to the development of both the Ly1- and Ly1+ B cell lineages in the mouse is discussed.

Lipopolysaccharide prevents apoptosis and induces responsiveness to antigen receptor cross‐linking in immature B cells

“…In pre-B cells, LPS induces transcription of immunoglobulin light chains, allowing progression to the immature (sIgM + sIgD 7 ) stage of development. 7,8 LPS treatment of immature B cells causes proliferation and increased expression of IgD, a marker associated with the mature B-cell stage. 9 Finally, exposure of mature B cells to LPS results in proliferation and differentiation into antibody-secreting plasma cells.…”