Lectin-dependent neutrophil cytotoxicity: enhanced susceptibility of desialylated red cells

Abstract

Lectin-dependent neutrophil cytotoxicity against autologous human red cells was studied using an 111In(indium)-release assay. Human red cells were not readily killed by neutrophils in the presence of phytohemagglutinin (PHA). However, removal of red cell membrane sialic acids (desialylation) markedly enhanced their susceptibility to PHA-dependent neutrophil cytotoxicity. This neutrophil cytotoxicity was dependent on the energy supplied by anaerobic glycolysis, but it was independent of erythrophagocytosis. Catalase, superoxide dismutase, KCN, and Na azide did not inhibit PHA-dependent neutrophil cytotoxicity. Neutrophils from a patient with chronic granulomatous disease, in the presence of PHA, also killed desialylated red cells normally. On the other hand, desialylation of neutrophils had no effect on the expression of their cytotoxic effect. The results suggest that desialylated red cells are much more susceptible to lectin-dependent neutrophil cytotoxicity than normal red cells, and that lectin-dependent neutrophil cytotoxicity is independent of reactive oxygen species.