THE SEPARATION OF DIFFERENT CELL CLASSES FROM LYMPHOID ORGANS

Abstract

Summary A method is presented for the separation of lymphoid cells on the basis of buoyant density. Up to 5 × 10 8 cells are dispersed in an isotonic, linear gradient of albumin in balanced salt solution at pH 5·1, and centrifuged at 3800 g. for 45 min at 4°. Density distribution profile for the cell population are calculated after determining the density, cell count and biological activity of about 30 fractions. The method maintains cells at their original volume and density, and gives around 90% cell recovery with little loss of biological activity. The position of a peak of cells is reproducible to ± 0·0003 g./cm 3 . The density distribution profiles of lymphocytes from many sources showed considerable heterogeneity, with several distinct peaks; control experiments suggested these were not products of the method. Lymphocyte populations appear to be composed of many sub‐populations separable on the basis of density.