| Immunotoxins are a novel class of cancer therapeutics that contains a cytotoxic agent fused to a targeting
moiety. Various toxic agents fromdifferent sources are used in immunotoxin development, including
bacterial, plant and human origin cytotoxic elements. Although bacterial and plant-derived toxins
are highly toxic and commonly used in immunotoxins, their immunogenicity for human restricted
their application in cancer therapy. Here, we discuss the advantages and limitations of bacterial toxins
such as Pseudomonas and Diphtheria toxins, plant toxins such as ricin and gelonin, and some
endogenous protein of human origin such as RNases and Granzymes. This article will also review different
generations of immunotoxinswith special focus on immunotoxinswhich are under clinical trials
or approved for clinical use. Finally, current deimmunization strategies for development of new lessimmunogenic
recombinant immunotoxins will be discussed. |