Purification of a lethal toxin produced by Shigella dysenteriae

A lethal toxin was purified from the culture supernatant of Shigella dysenteriae 1. The purification procedure utilized ammonium sulfate fractionation, column chromatography on DEAE-cellulose, CM-cellulose, hydroxylapatite and gel filtration on Sephadex G-200. About a 4760-fold purification was achieved, with a yield of 2.7%. The purified lethal toxin appeared homogeneous on polyacrylamide gel disc electrophoresis. The ld₅₀ of the purified lethal toxin in mice following i.p. injection was about 7.5 μg/kg. Injection i.p. of 2 ld₅₀ of the purified lethal toxin into mice caused paralysis of the limbs followed by death after 2–4 days.