Toxin-Based Therapeutic Approaches

Shapira, Assaf; Benhar, Itai

Among the bacterial toxins that were used for the construction of immunotoxins, the most common are diphtheria toxin and pseudomonas exotoxin A, which are naturally produced by the Gram-positive, aerobic Corynebacterium diphtheria and by the Gram-negative, aerobic Pseudomonas aeruginosa, respectively. Plant derived toxins, which belong to a group of toxins denoted "ribosome inactivating proteins" (RIPs), were also used in the preparation of immunotoxins. Among them, ricin, saporin and pokeweed antiviral protein (PAP), produced by Ricinus communis, Saponaria officinalis and Phytolacca americana, respectively, were most commonly used. All of these toxins are extremely potent and exert their toxicity by enzymatically inhibiting the protein synthesis machinery of eukaryotic cells (for additional reviews on immunotoxins, see [10] [11] [12] [13] [14] [15] [16] ).