Antibacterial activity in the coelomocytes of the sea urchin Paracentrotus lividus

Naturally present antibacterial activity directed against Vibrio alginolyticus was demonstrated in coelomocytes lysate (CL) and cell-free coelomic fluid (CF) of the marine echinoderm Paracentrotus lividus. Kinetic analysis revealed that 5 min of contact was enough to induce significant bactericidal effect. Maximum activity required 30 min of contact. Nonsensitive to the effect of trypsin, the activity was almost completely suppressed by incubation with subtilisin. Purified from CL by three successive steps of chromatography (gel filtration, anion exchange, reverse phase), active antibacterial protein appeared as a single polypeptide chain of approximate molecular weight of 60 kDa.