A non-covalent antibody complex for the delivery of anti-cancer drugs

Katia Maso, Isabella Monia Montagner, Antonella Grigoletto, Oddone Schiavon, Antonio Rosato, Gianfranco Pasut

Research output: Contribution to journalArticlepeer-review


Antibody drug conjugates (ADCs), which are obtained by coupling a potent cytotoxic agent to a monoclonal antibody (mAb), are traditionally bound in a random way to lysine or cysteine residues, with the final product's heterogeneity having an important impact on their activity, characterization, and manufacturing. A new antibody drug delivery system (ADS) based on a non-covalent linkage between a Fc-binding protein, in this case Protein A or Protein G, and a mAb was investigated in the effort to achieve greater homogeneity and to create a versatile and adaptable drug delivery system. Recombinant staphylococcal Protein A and streptococcal Protein G were chemically PEGylated at the N-terminus with a 5 kDa and a 20 kDa PEG, respectively, yielding two monoconjugates with a mass of ≈50 and ≈45 kDa. Circular dichroism studies showed that both conjugates preserved secondary structures of the protein, and isothermal titration calorimetry experiments demonstrated that their affinity for mAb was approximately 107 M-1. Upon complexation with a mAb (Trastuzumab or Rituximab), in vitro flow-cytometry analysis of the new ADSs showed high selectivity for the specific antigen expressing cells. In addition, the ADS complex based on Trastuzumab and Protein G, conjugated with a heterobifunctional 20 kDa PEG carrying the toxin Tubulysin A, had a marked cytotoxic effect on the cancer cell line overexpressing the HER2/neu receptor, thus supporting its application in cancer therapy.

Original languageEnglish
Pages (from-to)49-60
Number of pages12
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
Publication statusPublished - Sep 2019


  • Antibodies, Monoclonal/pharmacology
  • Antineoplastic Agents/pharmacology
  • Cell Line, Tumor
  • Drug Delivery Systems/methods
  • Humans
  • Immunoconjugates/pharmacology
  • Jurkat Cells
  • Receptor, ErbB-2/metabolism
  • Rituximab/pharmacology
  • Trastuzumab/pharmacology


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