Derivation of murine dendritic cells from thymic precursors

The earliest lymphoid precursor in the adult mouse thymus, the "low CD4 precursor," was found to be able to produce T cells, B cells, NK cells, and dendritic cells (DC) upon adoptive transfer (1-3). This precursor population represents only 0.03%-0.05% of total thymocytes and expresses low levels of CD4 and Thy-1, and positive for c-kit and CD44. The principle for isolating this minute precursor population is to enrich maximally for the population prior to fluorescence activated cell separation in order to reduce the cost and to maximize purity. A combination of density centrifugation and immunomagnetic bead depletion successfully removes mature and immature thymocytes and non-T-lineage cells. Note, it is important to deplete non-T-lineage cells, including erythrocytes, macrophages, and DC, which may otherwise contaminate the precursor preparation.