Generation and characterization of stromal cell independent IL-7 dependent B cell lines

In-vitro B cell cultures have played a significant role in the study of B cell development. Their utility in developmental and biochemical studies, however, has been limited by the challenges associated with obtaining and maintaining adequate cell numbers of pure and/or rare populations. Although B cell lines allow for circumvention of some of these issues, they have traditionally been generated via viral infection or genetic transformation and are thus less representative of in-vivo cells. In order to avoid such alterations in cell state, we have designed a procedure for the creation of B cell lines directly from murine bone marrow. In this study, we describe the generation and characterization of these IL-7 dependent cell lines. Our lines, established from both wild type and mutant mice, do not require stromal cell support for generation or maintenance. In addition, clones survive repeated freeze/thaw cycles and, in the presence of IL-7, can be kept in culture indefinitely. Phenotypically, our lines resemble pro/pre-B cells and exhibit IL-7 and preBCR signaling profiles that mimic ex-vivo B cells. These lines promise to be useful in the study of the signaling pathways that regulate B cell development.