The Effect of ATP Content of Human Erythrocytes on Immune Hemolysis

Previous work has shown that ATP-rich human erythrocytes are less sensitive to the action of antibody and complement than ATP-poor cells. Earlier studies by us had demonstrated that ATP content of red cells decreased concomitantly with the release of hemoglobin during immune hemolysis. It was postulated that antibody and complement may modify the membrane ATPase of human red cells. Portions of EA, mixed either with C′ or with EDTA-C′ were lysed by reducing the ionic strength. ATPase activity of ghosts was assayed in the presence or absence of ouabain. Ouabain-insensitive ATPase increased and reached a maximum within 5 min after addition of C′, whereas the release of hemoglobin was slightly delayed. ATPase activity of red cell ghosts prepared from EA and EDTA-C′ remained constant without any activation. ATPase activity of red cell ghosts that were prepared in the absence of A and C′ also increased when exposed to A and C′.