Sensitive manipulation of CAR T cell activity using a chimeric endocytosing receptor

Boning Zhang, John Victor Napoleon, Xin Liu, Qian Luo, Madduri Srinivasarao, Philip S. Low

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background Most adoptive cell therapies (ACTs) suffer from an inability to control the therapeutic cell's behavior following its transplantation into a patient. Thus, efforts to inhibit, activate, differentiate or terminate an ACT after patient reinfusion can be futile, because the required drug adversely affects other cells in the patient. Methods We describe here a two domain fusion receptor composed of a ligand-binding domain linked to a recycling domain that allows constitutive internalization and trafficking of the fusion receptor back to the cell surface. Because the ligand-binding domain is designed to bind a ligand not normally present in humans, any drug conjugated to this ligand will bind and endocytose selectively into the ACT. Results In two embodiments of our strategy, we fuse the chronically endocytosing domain of human folate receptor alpha to either a murine scFv that binds fluorescein or human FK506 binding protein that binds FK506, thereby creating a fusion receptor composed of largely human components. We then create the ligand-targeted drug by conjugating any desired drug to either fluorescein or FK506, thereby generating a ligand-drug conjugate with ∼10 -9 M affinity for its fusion receptor. Using these tools, we demonstrate that CAR T cell activities can be sensitively tuned down or turned off in vitro as well as tightly controlled following their reinfusion into tumor-bearing mice. Conclusions We suggest this € chimeric endocytosing receptor' can be exploited to manipulate not only CAR T cells but other ACTs following their reinfusion into patients. With efforts to develop ACTs to treat diseases including diabetes, heart failure, osteoarthritis, cancer and sickle cell anemia accelerating, we argue an ability to manipulate ACT activities postinfusion will be important.

Original languageEnglish (US)
Article numbere000756
JournalJournal for immunotherapy of cancer
Issue number2
StatePublished - Oct 30 2020


  • adoptive
  • chimeric antigen
  • immunotherapy
  • immunotherapy
  • receptors

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Molecular Medicine
  • Oncology
  • Pharmacology
  • Cancer Research


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