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  • Poster presentation
  • Open Access

Tri-functional T cell receptor antigen coupler (Tri-TAC): a novel method to direct T cells against tumors

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Journal for ImmunoTherapy of Cancer20142 (Suppl 3) :P17

  • Published:


  • Tumor Antigen
  • Costimulatory Molecule
  • Antigen Receptor
  • Chimeric Antigen Receptor
  • Signaling Domain

Engineering T cells with chimeric antigen receptors (CARs) is proving to be an effective method for directing T cells to attack tumors in an MHC-independent manner. Current generation CARs aim to recapitulate T cell signaling by incorporating modular functional components of the TCR and costimulatory molecules. Development of next generation CARs has relied upon trial and error evaluation of signaling domains. We sought to develop an alternate method to re-direct the T cell receptor which does not rely upon the incorporation of signaling domains into the chimeric receptor. To this end, we developed a tri-functional molecule which is membrane-anchored and redirects the TCR in the presence of tumor antigen. We also included components of the CD4 co-receptor to provide requisite Lck signaling upon ligation of the tumor antigen. Our prototype receptor was directed against the HER-2 proto-oncogene. We have determined that engineering peripheral blood T cells with this novel receptor (termed a Tri-TAC) engenders tumor-antigen specific activation of numerous T cell functions, including cytokine production, degranulation and cytolysis - equivalent to, if not greater than, a 2nd generation CAR bearing the CD28 and CD3zeta signaling domains. Future iterations of the engineered T cells will include chimeric costimulatory receptors to enhance T cell functionality and reduce off target toxicity. This research was supported by the Canadian Institutes of Health Research and the Terry Fox Foundation.

Authors’ Affiliations

McMaster University, Hamilton, Ontario, Canada


© Helsen et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.