Growing human B-cell precursors in vitro: the continuing challenge.

Methods for propagating murine B-cell precursors in vitro have been instrumental in unraveling the cells and molecules regulating murine B-cell ontogeny. However, similar methods are not available for studying human B-cell ontogeny. Here, Tucker LeBien discusses why efforts to grow human B-cell precursors in vitro have been largely unsuccessful and proposes alternative strategies that may prove useful.