Immune Hemolysis

Abstract

Abstract Enhancement of immune lysis of HK (MM) and LK (LM) sheep red cells by a high K+ medium did not require that the K+ be present during the action of rabbit hemolysin and complement on the cells. Preliminary exposure of these red cells to a high K+ buffer sufficed, and the K+ effect withstood vigorous washing of the treated cells. Enhancement of immune lysis by a high K+ medium was time, temperature and concentration dependent. It was also 80 to 90% inhibited by 10-4 M ouabain and much less effectively by equimolar G-strophanthidin, the aglycone of ouabain. The transition step from E* to ghost was not demonstrably affected by a high K+ medium. The ability of high concentrations of Rb+ or Li+ to enhance immune lysis was confirmed. Washing experiments suggested that these cations have lesser affinity for relevant sites on the red cell than K+, in the order K+ τ; Rb+ τ; Li+. The Rb+ and Li+ effects on lysis were also antagonized by ouabain. Although these phenomena suggest certain similarities to the stimulation of the traditional red cell Na+-K+ pump, several important differences exist. It is suggested that the K+-induced increment in immune lysis is not directly related to pump activity but possibly to conformational changes in the cell membrane influencing the effectiveness of complement.