Isolation of prolymphocytes from bone marrow and fetal liver

Isolation of the lymphoid progenitors in their earliest stage of development is indispensable for understanding when and how hematopoietic cell lineages are committed. Recently developed immunofluorescent labeling and sorting has made it possible to identify and isolate rare progenitors of lymphocytes. In this unit, protocols for isolating lymphoid progenitors from three different sources are provided. These protocols are based on stepwise purification consisting of magnetic and fluorescence-activated cell sorting techniques, optimized according to the nature of progenitors in each organ. Isolated progenitors may be analyzed in the lymphocyte differentiation cultures described in the following units and are useful for in vivo transfer experiments or microarray assays for gene expression.