CvL, a lectin from the marine sponge Cliona varians: Isolation, characterization and its effects on pathogenic bacteria and Leishmania promastigotes

Abstract CvL, a lectin from the marine sponge Cliona varians was purified by acetone fractionation followed by Sepharose CL 4B affinity chromatography. CvL agglutinated papainized treated human erythrocytes with preference for type A erythrocytes. The lectin was strongly inhibited by monosaccharide d -galactose and disaccharide sucrose. CvL is a tetrameric glycoprotein of 28 kDa subunits linked by disulphide bridges with a molecular mass of 106 kDa by SDS-PAGE and 114 kDa by Sephacryl S300 gel filtration. The lectin was Ca 2+ dependent, stable up to 60 °C for 60 min, with optimum pH of 7.5. CvL displays a cytotoxic effect on gram positive bacteria, such as Bacillus subtilis and Staphylococcus aureus . However, CvL did not affect gram negative bacteria, such as Escherichia coli and Pseudomonas aeruginosa . Leishmania chagasi promastigotes were agglutinated by CvL up to 2 8 titer. These findings are indicative of the physiological defense roles of CvL and its possible use in the antibiosis of bacteria and protozoa pathogenic.