Genetic engineering of an immunotoxin to eliminate pulmonary vascular leak in mice.

Vascular leak syndrome is a major and often dose-limiting side effect of immunotoxins and cytokines. We postulated that this syndrome is initiated by damage to vascular endothelial cells. Our earlier studies identified a three-amino acid motif that is shared by toxins, ribosome-inactivating proteins, and interleukin-2, all of which cause this problem.