Purification and some properties of exotoxin from Corynebacterium ulcerans strain ATCC 9015

Abstract Corynebacterium ulcerans strain ATCC 9015 develops during growth in environmental media an exotoxin which is lethal for guinea-pigs. The exotoxin has been purified by ion-exchange chromatography on DEAE-Sephadex A-50, affinity chromatography using immunosorbent techniques, and gel-filtration through Sephadex G-75. The exotoxin is of a protein nature and consists perhaps of two subunits. The molecular weights of the exotoxin and its subunits as estimated by SDS-PAGE were 40 000, 25 000, and 15 000, respectively. The toxic properties of exotoxin were destroyed upon heating (60°C, 30 min), treatment with trypsin (10 μ g/ml, 37°C, 30 min), and by the extremes of pH (pH 4.0 or 10.0; 24 hrs). Homologeous antibodies readily neutralized the exotoxin while commercial diphtheria antitoxin had no effects. No immunological cross-reactivity was revealed between exotoxin of C. ulcerans and other bacterial toxins such as diphtheria toxin, enterotoxin from V. cholerae , and exotoxin A of P. aeruginosa .