Inhibition of neutrophil oxidant secretion by D-penicillamine: scavenging of H2O2 and HOCl.

D-Penicillamine inhibited oxidant secretion from human neutrophils after activation by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe), as assessed by luminol dependent chemiluminescence. In contrast, this drug had little effect on either intracellular oxidant production or lucigenin dependent chemiluminescence activated by the same agonist. The drug was shown to scavenge both H2O2 and HOCl in a cell free luminol chemiluminescence system, though its ability to scavenge HOCl was greater than that for H2O2. Both these oxidants could oxidise the drug, but again HOCl was more potent than H2O2. When D-penicillamine was oxidised by exposure to H2O2 it could no longer serve as a scavenger of secreted oxidants from neutrophils. These data suggest that in vivo the preferential scavenging of HOCl may be important under pathological conditions where secreted myeloperoxidase may be functional.