Another common approach is to suspend the crude cells in a solution of Nycodenz® of density1.077 g/ml to allow the DCs to float to the top during centrifugation, while all of the denser cells pellet(e.g. refs 6-9). 

This strategy too has been adapted to OptiPrep™, but to improve the purity of the DCsthere has been a tendency to reduce the density of the suspending solution (approx 1.061 g/ml). Thisseparation protocol was first described for the isolation of DC from mouse Peyer’s patches, lymphnodes and spleen and for the isolation of Langerhans cells from skin [10-12]. 

The method is describedin this Application Sheet and it is the easiest of all the methods to execute.A third option, also a flotation technique is as follows: the cell suspension is adjusted to a densityof 1.085 g/ml with OptiPrep™and the DC allowed to float up through an iodixanol solution of density1.065 g/ml layered on top. This is described in “Dendritic cells” Application Sheet C21, see index