BINDING OF OUABAIN TO NORMAL AND CHRONIC LYMPHOCYTIC LEUKEMIC LYMPHOCYTES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 54  (5) , 994-1000
Abstract
The binding of the cardiac glycoside, ouabain, to cells was used to quantify the number of active cation pumps. Lymphocytes were incubated with 3H-ouabain and the equilibrium binding analyzed for the maximal number of specific binding sites. Lymphocytes from normal peripheral blood bound 44,200 .+-. 9920 molecules/cell, compared with 29,200 .+-. 8370 molecules/cell for the lymphocytes of chronic lymphocytic leukemia (CLL) subjects. This difference was significant (P < 0.01) and did not reflect a lower number of sites on B [bone marrow-derived] cells than T [thymus-derived] cells, since B cell-enriched lymphocytes from normal peripheral blood showed the same ouabain binding characteristics as the standard T cell-rich preparation. Although monocytes bound 3-fold more ouabain than lymphocytes, the small monocyte contamination (3.0%) in normal lymphocyte preparations could not account for the difference between normal and CLL. The fewer ouabain binding sites on CLL lymphocytes may reflect their smaller size (by 10%) and lower mitotic activity compared with lymphocytes from normal peripheral blood.