Adnectin-Based Design of Chimeric Antigen Receptor for T Cell Engineering

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Chimeric antigen receptor (CAR) T-cell therapy shows success in hematological cancers but requires optimization for broader application.
• Current CAR constructs often use non-human single chain variable fragments (scFvs), which can cause immunogenicity, limiting CAR T-cell persistence and efficacy.
• Limited availability and slow discovery of scFvs hinder the development of novel CAR constructs.

Purpose of the Study:

• To evaluate adnectin as a potential alternative to scFv for antigen binding in CAR T-cell therapy.
• To construct and assess adnectin-based CARs targeting the epithelial growth factor receptor (EGFR).

Main Methods:

• Engineered T-cells with adnectin-based CARs targeting EGFR.
• Compared adnectin-CAR T-cells with scFv-CAR T-cells in vitro for cell-killing activity against H292 lung cancer cells.
• Evaluated antitumor efficacy of adnectin-CAR T-cells in vivo using xenograft tumor models.
• Assessed selectivity of adnectin-CAR T-cells on target cells with varying EGFR expression levels.

Main Results:

• Adnectin-based CAR T-cells exhibited equivalent in vitro cell-killing activity compared to scFv-based CAR T-cells.
• Comparable antitumor efficacy was observed in vivo in xenograft tumor models.
• Adnectin-based CARs demonstrated higher selectivity for target cells with high EGFR expression after affinity tuning.

Conclusions:

• Adnectin serves as a viable alternative to scFv for antigen recognition in CAR T-cell design.
• Adnectin-based CAR T-cells offer comparable efficacy and potentially improved selectivity, facilitating broader T-cell immunotherapy development.
• This approach may enhance the therapeutic potential of CAR T-cell therapy for various cancers and other diseases.