Partial characterization of leukocidin from Fusobacterium necrophorum.

Leukocidin from Fusobacterium necrophorum was produced in the diffusate of a dialysis culture. It was free from deoxyribonuclease, fibrinolysin, gelatinase, haemolysin, lipase, caseinase and endotoxin. The leukocidin had a molecular weight between 10,000 and 5,000 as estimated by membrane partition chromatography. It formed precipitin lines with anti-leukocidin-serum in double immunodiffusion tests. Mouse peritoneal cells were characteristically damaged by the leukocidin, as revealed by scanning electron microscopy. The damaged cells lost microvilli and suffered partial destruction of their cell membranes.