The Morphology, Lifetime, and Pore Size of Complement Lesions on Erythrocyte Membranes

The action of complement on sensitized erythrocytes (EA) results in release of hemoglobin (Hb) with concomitant formation of cell ghosts (EAC · gh). Prior cross-linking of EA with 0.025% glutaraldehyde (EA · X) prevents release of Hb upon incubation with C but not of trapped ions such as ⁸⁶Rb indicating a limiting pore size of the lesion. The mechanism or entity that allows Hb release from EA, however, remains only transiently functional since EAC · gh reseal again. Using a simple sucrose-step-gradient centrifugation assay we found that more than 80% of EAC·gh are impermeable to molecules of the size of sucrose. In contrast, resealed ghosts, prepared from EA by hypotonic lysis and subsequent incubation with isotonic buffer (EA · gh), that have been cross-linked (EA · gh · X) remain permeable after incubation with complement (EA · gh · X · C). The successful introduction of C dependent pores into EA · gh · X depends on the amount of cross-linking.