Isolation of lymphocyte populations.

Lymphocytes are smaller than most mammalian cells. Although their densities are heterogeneous and overlap those of other mammalian cells, the average lymphocyte is less dense than the vast majority of mammalian cells. Because of these physical properties, lymphocytes sediment less rapidly than most mammalian cells during velocity sedimentation in the isokinetic gradient. Our separations of lymphocytes from several kinds of tissues including human blood, transplantable tumors, and the tumor of Hodgkin's disease are described.