STUDIES ON TERMINAL STAGES OF IMMUNE HEMOLYSIS .3. DISTINCTION BETWEEN INSERTION OF C9 AND FORMATION OF A TRANSMEMBRANE CHANNEL

Abstract

The intermediate product EAC1-8 [sheep red blood cells-antibody-complement components 1-8] released cytoplasmic components as a result of at least 2 sequential reactions after its interaction with C9. Binding of C9 to EAC1-8 occurred in a few minutes even at 0.degree. C. Trypsinization of EAC1-9 prepared and held at low temperature resulted in nullification of the potential hemolysis of these cells. A brief incubation at 30 or 37.degree. C resulted in the formation of an intermediate whose hemolytic potential could not be nullified by trypsin. The failure of trypsin to nullify hemolysis was attributed to the insertion of C9 into the cell membrane. Studies on the effect of EDTA or low temperature suggested that the reported temperature-dependent step in E* formation described by Frank et al. was the insertion of C9. 86Rb-labeled EAC1-8 studies indicated that a transmembrane channel was not formed until after the C9 was inserted and a further reaction or reactions occurred.