Evidence that superoxide-anion, produced by PMA-activated human polymorphonuclear leukocytes, is the cytolytic agent for rabbit, but not for sheep red blood cells

The lysis of sheep and rabbit red blood cells (SRBC and RRBC, respectively) upon exposure to PMA-activated human polymorphonuclear leukocytes (PMN) was investigated. The lysis of these target cells, which was measured by the release of ⁵¹Cr, showed different kinetics and scavenger-sensitivity. The lysis of RRBC, which was already detectable within 45 min of incubation, was sensitive to superoxide dismutase (SOD), but was only poorly influenced by scavengers of hydroxyl radical formation, such as desferal or thiourea. In contrast, lysis of SRBC was first detectable after 90 to 135 min of incubation and sensitive to desferal and thiourea, but not to SOD. Finally, only RRBC were sensitive to the artificial superoxide-generating system hypoxanthine/xanthine oxidase. Taken together, these data point at a cytolytic activity of superoxide anion O₂^- towards RRBC. SRBC are relatively resistant to O₂^-, but are lysed by an H₂O₂- and hydroxyl radical-dependent process.