Therapeutic targets and recent advances in protein immunotoxins

Targeted therapy has replaced the conventional methods of disease management with the advances in recombinant technology and increased understanding of molecular mechanisms of diseases. The immunotoxin strategy for diseases like cancer and a variety of autoimmune disorders has been used successfully in the past since its discovery. Since bacterial, fungal and plant toxins have various limitations like toxicity and immunogenicity, studies on fully humanized immunotoxins have gained attraction recently, which reduced toxicity significantly. Improved methods of antibody engineering have led to the emergence of various new formats of immunotoxins. This review summarizes the target moieties used in immunotoxin constructs in different diseases and describes the recent advances in immunotoxin targeting.

► Immunotoxins (ITs) are used for targeted therapy of cancer and auto-immune diseases.
► Cytokine and growth factor receptors or specific surface antigens are targeted.
► IT constructs have been used in clinical trials and one is FDA approved for therapy.
► Immunogenicity, toxicity and tumor penetration are major challenges for IT therapy.
► Recent formats with human proteins or bispecific antibodies overcome limitations.