Rationally Designed Transgene-Encoded Cell-Surface Polypeptide Tag for Multiplexed Programming of CAR T-cell Synthetic Outputs
Adam J Johnson, Jia Wei, James M Rosser, Annette Künkele, Cindy A Chang, Aquene N Reid, Michael C Jensen, Adam J Johnson, Jia Wei, James M Rosser, Annette Künkele, Cindy A Chang, Aquene N Reid, Michael C Jensen
Abstract
Synthetic immunology, as exemplified by chimeric antigen receptor (CAR) T-cell immunotherapy, has transformed the treatment of relapsed/refractory B cell-lineage malignancies. However, there are substantial barriers-including limited tumor homing, lack of retention of function within a suppressive tumor microenvironment, and antigen heterogeneity/escape-to using this technology to effectively treat solid tumors. A multiplexed engineering approach is needed to equip effector T cells with synthetic countermeasures to overcome these barriers. This, in turn, necessitates combinatorial use of lentiviruses because of the limited payload size of current lentiviral vectors. Accordingly, there is a need for cell-surface human molecular constructs that mark multi-vector cotransduced T cells, to enable their purification ex vivo and their tracking in vivo. To this end, we engineered a cell surface-localizing polypeptide tag based on human HER2, designated HER2t, that was truncated in its extracellular and intracellular domains to eliminate ligand binding and signaling, respectively, and retained the membrane-proximal binding epitope of the HER2-specific mAb trastuzumab. We linked HER2t to CAR coexpression in lentivirally transduced T cells and showed that co-transduction with a second lentivirus expressing our previously described EGFRt tag linked to a second CAR efficiently generated bispecific dual-CAR T cells. Using the same approach, we generated T cells expressing a CAR and a second module, a chimeric cytokine receptor. The HER2txEGFRt multiplexing strategy is now being deployed for the manufacture of CD19xCD22 bispecific CAR T-cell products for the treatment of acute lymphoblastic leukemia (NCT03330691).
Conflict of interest statement
Conflict of Interest Statement: M.C.J. has interests in Umoja Biopharma and Juno Therapeutics, a Bristol-Myers Squibb company. He is a seed investor and holds ownership equity in Umoja, serves as a member of the Umoja Joint Steering Committee, and is a Board Observer of the Umoja Board of Directors. M.C.J. also holds patents, some of which are licensed to Umoja Biopharma and Juno Therapeutics. M.C.J. and A.J.J. are inventors on issued and pending patents for the HER2t and EGFRt surface tags, and Seattle Children’s Hospital is an applicant. All other authors report no conflicts of interest.
©2021 American Association for Cancer Research.
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Source: PubMed