The use of flow cytometry to measure glucocorticoid-induced killing of lymphoid cell lines.

A flow cytometer method was developed to measure glucocorticoid-induced death in sensitive lymphoid cells. The murine lymphoma cell lines, R1.1, S49.1 and WEHI 7.1, and the human T-lymphocyte cell line, MOLT-4, were exposed to 10(-8) to 10(-6) mol/L dexamethasone or methylprednisolone. The cytogram for unstained, unfixed cells, produced by plotting the axial light loss versus the right-angle scatter using a He-Ne laser as the light source, showed two clearly separated peaks corresponding to live and dead cells. The ratio of live to dead cells seen in the cytogram correlated with that obtained by trypan blue staining. The flow cytometry method offers a number of advantages: 300 to 500 cells/s can be counted, yielding speed and good counting statistics; unstained, unfixed cells can be used; and the live and dead cells can be sorted for plating or biochemical analysis. S49.1 and R1.1 cells were sensitive to methylprednisolone and dexamethasone in the 10(-6) to 10(-8) mol/L concentration range, while MOLT-4 and WEHI 7.1 cells were less sensitive. After a 48-h exposure to 10(-8) mol/L dexamethasone, S49.1 and R1.1 cell cultures had 30% and 38% dead cells, respectively, while WEHI 7.1 and MOLT-4 cell cultures had less than 5% dead.