Denileukin diftitox

Denileukin diftitox is a fusion protein composed of truncated diphtheria toxin (DT), which is a cytocidal moiety, and the full-length sequence of interleukin-2 (IL-2), which acts as a ligand for the IL-2 receptor. Denileukin diftitox is reported to bind to a high- or intermediate-affinity receptor. Once the drug molecule binds to the IL-2 receptor, denileukin diftitox is internalized via receptor-mediated endocytosis in an acidified vesicle. After uptake into the cell, denileukin diftitox is proteolytically cleaved within the endosomes to release the enzymatically active portion of the DT. DT is translocated across the endosomal membrane into the cytosol to inhibit protein synthesis via ADP-ribosylation of elongation factor-2, ultimately resulting in cell death. The fragment of DT is translocated across the endosomal membrane into the cytosol where it inhibits protein synthesis via ADP-ribosylation of elongation factor-2, resulting in cell death.