BCR Ligation Induces Receptor Editing in IgM+IgD− Bone Marrow B Cells In Vitro

Abstract The ability of BCR cross-linking to stimulate receptor editing was analyzed in vitro using bone marrow B cells from immunoglobulin (Ig) transgenic (Tg) and non-Tg mice. In cultured Ig-Tg cells, BCR ligation induced receptor editing as measured by up-regulation of RAG gene expression, light chain gene DNA rearrangements, and expression of λ-light chain protein in cells that previously expressed κ. In the culture conditions used, BCR ligation induced light chain rearrangements in most immature IgM + IgD − bone marrow B cells in the absence of significant cell death or cell growth. Receptor editing in non-Tg B cells was also documented in cultures treated with anti-immunoglobulin. These results provide direct evidence for the ability of BCR ligation to stimulate immunoglobulin light chain gene rearrangements in immature B cells.