Modifications outside CDR1, 2 and 3 of the TCR variable β domain increase TCR expression and antigen-specific...

Area of Science:

• Immunology
• Biotechnology
• Molecular Biology

Background:

• T cell receptor (TCR) gene-modified T cells are a key adoptive cellular therapy for cancers and viral infections.
• Enhancing therapeutic TCR surface expression and minimizing endogenous TCR mis-pairing are critical for efficacy and safety.
• Previous strategies focused on improving TCRs, but framework residue modifications remain underexplored.

Purpose of the Study:

• To investigate the impact of framework residue modifications in TCR variable domains on TCR expression and function.
• To identify specific amino acid residues in the TCR variable β domain framework that enhance surface expression.
• To assess the effect of these modifications on T cell-mediated cytotoxicity and potential toxicity.

Main Methods:

• Utilized bioinformatic and protein structural analyses to predict key framework residues in TCR variable domains.
• Engineered T cells with modified TCRs by altering identified framework residues.
• Assessed surface expression levels of engineered TCRs using flow cytometry.
• Quantified target cell-specific killing by engineered T cells.
• Evaluated potential for TCR mis-pairing and associated toxicities.

Main Results:

• Bioinformatic and structural analyses identified candidate framework residues in the TCR variable β domain.
• Modification of these residues in poorly expressed TCRs significantly improved surface expression.
• Engineered T cells expressing modified TCRs demonstrated enhanced target cell-specific killing.
• These modifications also reduced the risk of toxicity linked to TCR mis-pairing.

Conclusions:

• Small alterations within the framework of TCR variable domains can substantially enhance TCR surface expression and functionality.
• This strategy offers a promising approach to improve the efficacy of TCR engineered T cell therapy.
• Modifying framework residues presents a viable method to boost therapeutic T cell activity while mitigating safety concerns like TCR mis-pairing.