Abstract LB-090: Sequence-based discovery of fully human anti-CD3 and anti-PDL1 single domain antibodies using novel transgenic rats

We have created a new platform and method for discovering fully human single domain antibodies (UniDabs) by combining novel transgenic rats (UniRats), antibody repertoire sequencing, and high-throughput gene assembly, expression and screening. UniRats express a comprehensive human VH gene repertoire in a heavy chain only antibody format, and they mount robust immune responses to a variety of antigens. UniRats do not produce endogenous Ig as their heavy, kappa and lambda loci have been silenced, so the only Ig expression comes from the human heavy chain transgenes. Human VHs identified using high-throughput functional screening of heavy chain antibodies may also be converted to a single domain UniDab format. UniDabs are powerful and flexible modular binding domains that may be combined to form multivalent structures, nanoparticle conjugates, or antibody-drug conjugates. In our preclinical CD3 and PDL1 programs, we have identified hundreds of antigen-specific UniDabs. This large collection of UniDabs covers a diverse set of epitopes, a wide range of affinities, and is a valuable resource for creating next-generation multi-specific cancer therapeutics. Citation Format: Nathan Trinklein, Shelley Force Aldred, Ute Schellenberger, Kat Harris, Starlynn Clarke, Kevin Dang, Duy Pham, Marianne Bruggemann, Wim vanSchooten. Sequence-based discovery of fully human anti-CD3 and anti-PDL1 single domain antibodies using novel transgenic rats. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-090.