Inhibition of protein synthesis by a toxic lectin from Viscum album L. (mistletoe)

Abstract
The hemagglutinating and toxic lectin from V. labum (mistletoe) inhibits protein synthesis in a lysate of rabbit reticulocytes, with an ID50 (concentration giving 50% inhibition) of 2.6 .mu.g/ml. This effect is enhanced (ID50 0.21 .mu.g/ml) if the lectin is reduced with 2-mercaptoethanol. The lectin inhibits protein synthesis also in BL8L cells in culture. Inhibition occurs after a lag time of 3 h. The ID50 is 7 ng/ml, and increases after reduction of the lectin. This and the gross lesions observed in rats poisoned with V. album lectin indicate this is a toxin very similar to ricin.