Peroxidase-release associated with phagocytosis in Mytilus galloprovincialis haemocytes

Fluorescence spectra of the supernatant of adherent haemocyte monolayers from Mytilus galloprovincialis, supplemented with homovanillic acid or with a tyrosyl peptide glycylglycyltyrosine (GGY), were recorded before and after stimulation by zymosan. The formation of fluorescent derivatives was observed to have spectral characteristics similar to those of fluorescent compounds generated by the exposure of homovanillic acid or GGY to a horseradish peroxidase/hydrogen peroxide system in vitro. Lucigenine-enhanced chemiluminescence (CLluc) of M. galloprovincialis haemocytes stimulated by zymosan or by phorbol ester (PMA) was measured in the presence and absence of sodium azide, a peroxidase inhibitor. Sodium azide inhibited the CLluc of haemocytes stimulated by zymosan, an effective stimulus for myeloperoxidase secretion in human polymorphonuclear leukocytes, but not the CLluc of haemocytes stimulated by PMA, indicating the presence of peroxidases with some properties of myeloperoxidase, in adherent haemocytes from M. galloprovincialis.