Rationally Designed Transgene-Encoded Cell-Surface Polypeptide Tag for Multiplexed Programming of CAR T-cell...

Area of Science:

• Synthetic immunology
• Cancer immunotherapy
• Molecular engineering

Background:

• Chimeric antigen receptor (CAR) T-cell therapy is effective for B-cell malignancies but faces challenges in solid tumors.
• Barriers include limited tumor homing, microenvironment suppression, and antigen escape.
• Multiplexed engineering with multiple lentiviruses is needed but requires methods to track cotransduced cells.

Purpose of the Study:

• To develop a cell-surface tag for marking and purifying multiplexed vector-cotransduced T cells.
• To enable the generation and tracking of T cells engineered with multiple synthetic constructs.

Main Methods:

• Engineered a truncated human HER2-based tag (HER2t) retaining a trastuzumab epitope for cell surface localization.
• Linked HER2t to CAR expression in lentivirally transduced T cells.
• Demonstrated cotransduction with a second lentivirus expressing an EGFRt tag linked to a second CAR to create bispecific dual-CAR T cells.

Main Results:

• Successfully generated bispecific dual-CAR T cells using the HER2t and EGFRt multiplexing strategy.
• Demonstrated the generation of T cells expressing a CAR and a chimeric cytokine receptor.
• The HER2txEGFRt strategy is being used for CD19xCD22 bispecific CAR T-cell products for acute lymphoblastic leukemia.

Conclusions:

• The HER2txEGFRt multiplexing strategy provides a method for engineering and tracking complex T-cell therapies.
• This approach facilitates the development of advanced CAR T-cell products for challenging cancers.
• Enables purification and in vivo tracking of multi-vector cotransduced T cells for improved therapeutic efficacy.