Balanced secretion of anti-CEA × anti-CD3 diabody chains using the 2A self-cleaving peptide maximizes diabody assembly and tumor-specific cytotoxicity

• DOI: 10.1038/gt.2017.3
• Publication Date: 2017-01-11T15:41:17Z
• Authors: K Mølgaard; M Compte; N Nuñez-Prado; S L Harwood; L Sanz; L Alvarez-Vallina
• Keywords: Carcinoembryonic antigen

Adoptive transfer of genetically engineered human cells secreting bispecific T-cell engagers has shown encouraging therapeutic effects in preclinical models cancer. However, reducing the toxicity and improving effectiveness this emerging immunotherapeutic strategy will be critical to its successful application. We have demonstrated that for gene-based antibody strategies, two-chain diabodies a better safety profile than single-chain tandem scFvs (single-chain variable fragments), because their reduced tendency form aggregates reduces risk inducing antigen-independent activation. Here, we demonstrate incorporation 2A self-processing peptide derived from foot-and-mouth disease virus conveying co-translational cleavage into anti-CD3 × anti-CEA diabody gene enables near-equimolar expression chains 1 2, thus increases final amount assembled diabody. This was found maximize diabody-mediated activation cytotoxicity against carcinoembryonic antigen-positive tumor cells.