Quantitative Studies on the Sensitivity to Complement Lysis of Red Cells Treated With Thiol-reactive Reagents

The effect of reduced glutathione on the complement sensitivity of normal and paroxysmal nocturnal hemoglobinuria (PNH) red cells was determined quantitatively. The susceptibility to complement lysis was increased in normal and complement-sensitive and complement-insensitive PNH cells; the percentage increase in susceptibility was inversely related to the initial complement-sensitivity. P-chloromercuribenzene sulfonate (PCMBS) likewise increased the sensitivity of normal cells to lysis by complement; the effect with both compounds appeared to be due to reaction with membrane thiol groups. GSH-treated normal cells were similar to PNH cells in that the susceptibility to immune lysis occurred without concomitant increase in fixation of antibody or first component of complement. GSH-treated normal cells differed from PNH cells in that the membrane acetylcholinesterase activity was normal and the cells were not stable during preparation and short-term storage.