T cell immunotherapy uses a patient’s own T cells to fight cancerous cells. A new approach in T cell immunotherapy under investigation uses a small protein tag to hasten and improve the immunotherapy’s ability to attack cancer cells, according to a recent study published in Nature Biotechnology.1

In this new approach, a patient’s T cells can be engineered to contain a protein tag, in this case a Strep-tag II, which allows for rapid purification, optimal function, and large-scale expansion. Stanley Riddell, MD, of the Fred Hutchinson Cancer Research Center, Clinical Research Division, Program in Immunology and professor at the University of Washington’s Department of Medicine, Seattle, led the research team.

This study examined the effects of the Strep-tag II on T cells in cancerous human cell lines and in a mouse model of lymphoma; the approach is not yet studied in humans. One major benefit of this new approach is that it enabled live tracking and retrieval of Strep-tag II-engineered T cells for downstream research applications.

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According to these results, this Strep-tag II approach might boost T cells’ potency and could be scaled up to grow large quantities of cancer-fighting T cells. Additionally, this approach contains a kill switch such that the engineered T cells could be deactivated in case of toxic side effects. Finally, the cell processing with this new approach is 9 days or less, whereas previous cell processing times ranged from 14 to 20 days.

“Collectively, our studies show that the addition of Strep-tag II provides a receptor-intrinsic surface marker that endows engineered T cells with multiple functionalities, facilitating cost-effective and efficient current good manufacturing practice, in vivo monitoring and analysis of therapeutic cell products in clinical applications,” concluded the authors.

A biotechnology company, Juno Therapeutics, has an exclusive license to the Strep-tag II method for uses related to oncology as well as a nonexclusive license for other purposes.


1. Liu L, Sommermeyer D, Cabanov A, Kosasih P, Hill T, Riddell SR. Inclusion of Strep-tag II in design of antigen receptors for T-cell immunotherapy [published online ahead of print February 22, 2016]. Nat Biotechnol. doi:10.1038/nbt.3461.