An improved isolation method for murine migratory cutaneous dendritic cells.

Dendritic cells are highly specialized accessory cells for the initiation of primary immune responses. They occur as trace populations in non-lymphoid and lymphoid organs. Therefore, the isolation and enrichment of primary dendritic cells is difficult and time-consuming. This applies also to dendritic cells from skin, i.e. epidermal Langerhans cells and dermal dendritic cells. Recently introduced skin organ cultures serve as a convenient source for primary cutaneous dendritic cells. We report here a refinement of such cultures in which cutaneous dendritic cells emigrate spontaneously into the culture medium. Murine ear skin is cultured for a total of 3 days in three sequential 24 h steps. This simple modification doubles or triples the yields of dendritic cells that can be obtained and up to 30,000 dendritic cells can be recovered from one ear half. This represents 50-70% (range 30-80%) of all viable cells. The cells are mature dendritic cells that possess potent T cell stimulatory function. Compared to the classical methods of preparing epidermal Langerhans cells by trypsinization this technique is easier and quicker; it does not require enzymes such as trypsin, and it yields similar numbers of mature dendritic cells. It should prove useful for further studies of dendritic cells of the skin.