Immunotoxins kill target cells by:
Immunotoxins constitute chimeric fusion therapeutics coupling targeting domain, typically single-chain variable fragment scFv or Fab derived from monoclonal antibody recognizing tumor-associated antigen like CD22 or HER2, to potent catalytic toxin of bacterial or plant origin including Pseudomonas exotoxin A fragment PE38, diphtheria toxin DT390, ricin A chain, saporin or gelonin. Mechanism begins with antigen-specific binding, internalization via clathrin-mediated endocytosis into early endosome, pH-dependent furin cleavage between targeting and toxin domains, retrograde transport via KDEL re
Ref: Pastan et al. Nature Reviews Cancer 2006 Immunotoxins; Weldon & Pastan FEBS J 2011 mechanism; PubMed PMID 16794637.
