The role of reactive oxygen intermediates in nonspecific monocyte cytotoxicity induced by immune complexes

GEFFNER J; GIORDANO M; SEREBRINSKY G; ISTURIZ, MA

clinical and experimental immunology

Wiley

Año: 1987

1365-2249

Normal human monocytes were induced to lyse nonsensitized target cells when triggeredby precipitating immune complexes (IC) or soluble heat-aggregated IgG (HAIgG).Catalase, azide, cyanide and three aminoacids employed as quenchers of CIO-,significantly inhibited this nonspecific cytotoxicity (NSC), suggesting an important rolefor the myeloperoxidase (MPO) system. However, HO and/or '02 may also be involvedin the lysis, since certain scavengers of these species such as mannitol, benzoate, ethanoland hystidine, as well as superoxide dismutase (SOD), partially inhibited NSC. Moreover,cyanide and azide were unable to completely abrogate this lytic activity. When NSC wascompared to antibody dependent cellular cytotoxicity (ADCC), it was found that neithercatalase nor oxygen-species scavengers affected ADCC while azide and cyanidesignificantly enhanced it. Antibody-coated target cells were also destroyed by IC-triggeredmonocytes. However, kinetic analysis and studies on the capacity of catalase to inhibit thelysis demonstrated that it was mediated through a NSC-like mechanism. The cytotoxicsystem described in this report offers a suitable model to study in vitro alternative lyticmechanisms triggered through monocyte receptors for the Fc portion of IgG (FcyR).