Quantitative Control of Gene-Engineered T-Cell Activity through the Covalent Attachment of Targeting Ligands to a Universal Immune Receptor

Abstract

<p class="first" id="P1">Universal immune receptors represent a rapidly emerging form of adoptive T-cell therapy with the potential to overcome safety and antigen escape challenges faced by conventional chimeric antigen receptor (CAR) T-cell therapy. By decoupling antigen recognition and T-cell signaling domains via bifunctional antigen-specific targeting ligands, universal immune receptors can regulate T-cell effector function and target multiple antigens with a single receptor. Here, we describe the development of the SpyCatcher immune receptor, the first universal immune receptor that allows for the post-translational covalent attachment of targeting ligands at the T-cell surface through the application of SpyCatcher-SpyTag chemistry. The SpyCatcher immune receptor redirected primary human T cells against a variety of tumor antigens via the addition of SpyTag-labeled targeting ligands, both in vitro and in vivo. SpyCatcher T-cell activity relied upon the presence of both target antigen and SpyTag-labeled targeting ligand, allowing for dose-dependent control of function. The mutational disruption of covalent bond formation between the receptor and the targeting ligand still permitted redirected T-cell function but significantly compromised antitumor function. Thus, the SpyCatcher immune receptor allows for rapid antigen-specific receptor assembly, multiantigen targeting, and controllable T-cell activity. </p><p id="P2"> <div class="figure-container so-text-align-c"> <img alt="" class="figure" src="/document_file/6d7fdafa-62e3-4de5-bdc9-603823c51d24/PubMedCentral/image/nihms-1588493-f0001.jpg"/> </div> </p>