Cytolysis mediated by phagocytosing neutrophils. Influence of the presence of an alternative target cell population.
When added to the hypochlorous acid (HOCl)-dependent cytolytic system constituted of opsonized zymosan (OPZ)-triggered neutrophils and chicken erythrocyte (CRBC) targets, human erythrocytes (HRBCs) inhibited the lysis. The replacement of HRBCs with cells pretreated with amino-triazole (AT) to inactivate catalase prevented the HRBC inhibitory effect almost completely. HRBCs, pretreated with carmustine (BCNU) to inhibit glutathione cycle activity, behaved as untreated cells. Thus, HRBCs appear to protect CRBCs via an AT-inhibitable, i.e. catalase-dependent, process. When measured under conditions similar to those used for the lytic assay, both the hydrogen peroxide (H2O2) and the HOCl recovery from the neutrophil-CRBC system was reduced by HRBCs and restored by pulsing HRBCs with AT but not BCNU. The results suggest that HRBC catalase rescues CRBCs from neutrophil-delivered attack by "stealing" H2O2 from the neutrophil HOCl-generating myeloperoxidase (MPO)-H2O2 system.
Dallegri
F
F
First Medical Clinic, University of Genova Medical School, Italy.
Ballestrero
A
A
Goretti
R
R
Ottonello
L
L
Patrone
F
F
D000818:Animals; D002374:Catalase / Q000378:metabolism; D002645:Chickens; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism / Q000502:physiology*; D010587:Phagocytosis
D006861:Hydrogen Peroxide; D002374:Catalase